Macrocyclic SalenâBis-NHC Hybrid Ligands and Their Application to

Article pubs.acs.org/Organometallics

Macrocyclic Salen−Bis-NHC Hybrid Ligands and Their Application to the Synthesis of Enantiopure Bi- and Trimetallic Complexes Melanie Mechler, Wolfgang Frey, and René Peters* Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany S Supporting Information *

ABSTRACT: Salen and NHC ligands are among the most important ligands for homogeneous catalysis. We have recently reported bimetallic complexes, in which both motifs have been merged for the first time. However, the intermetallic distances, which play a crucial role for cooperative bimetallic catalysis, were probably not appropriate in these first-generation hybrid catalysts. To generate heterobimetallic salen/NHC hybrid complexes with intermetallic distances suitable for cooperative catalysis, chiral macrocyclic hybrid ligands featuring a salen and two linked NHC donor moieties have been prepared in the present study. For the ligand formation, chiral enantiopure diamines as well as chiral enantiopure bisimidazoles were employed, and a matched/mismatched situation was found depending on the configuration of both chirality sources. Regioselective complexation of Zn(II), Ni(II), and Pd(II) by the salen N2O2 coordination sphere was efficiently accomplished. Subsequent coordination of the NHC units was achieved for Ag(I), Cu(I), Au(I), and Pd(II), in the latter case by oxidative transmetalation with Pd2(dba)3. X-ray crystal structure analyses for Ni/Ag2 and Pd/Ag2 complexes show strongly puckered macrocycles, in which one of the NHC-bound Ag(I) centers is in close proximity to the salen-bound Ni(II) or Pd(II) centers and in which this Ag(I) apparently interacts with both salen O-donor atoms. Preliminary data for the 1,4-addition of an oxindole to a nitroolefin and for the Conia-ene reaction of an α-cyanoacetate are reported.

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INTRODUCTION The intramolecular cooperation of two metal centers in bimetallic complexes has emerged as a very attractive strategy in catalysis,1 which is also frequently applied in nature by dinuclear metalloenzymes.2 Like in these enzymes, the synergistic activation of two reactants (or functional groups) by simultaneous coordination to the different metal centers in an artificial bimetallic complex can significantly reduce the activation barrier for the formation of covalent bonds between both reactants. Another major advantage of such a dual activation strategy is often given by enhanced stereoselectivities as compared to more traditional monometallic catalyst systems, because interaction of both substrates with the activating metal centers of one catalyst molecule facilitates a defined spatial preorganization of both substrates in the stereodefining transition state. This explains why bimetallic catalysts are often very useful for asymmetric catalysis. In addition, they are now also intensively investigated in macromolecular chemistry as very efficient polymerization catalysts.3 In our program directed toward cooperative asymmetric catalysis,4,5 we have recently developed a first approach toward salen−bis-NHC hybrid ligands for a modular formation of bimetallic complexes, in which the features of metal salen6 and NHC complexes7two of the most abundant structural motifs in homogeneous catalystshave been merged (Figure 1, left).8 The salen coordination sphere can, in general, be used for the complexation of a large number of different metal ions,6,9,10 © XXXX American Chemical Society

Figure 1. General modular design of dinuclear salen−bis-NHC complexes. Left: open bimetallic salen−NHC hybrid complexes from our previous study.8 Right: closed bimetallic complexes from this study.

while NHC ligands have a considerably higher binding affinity to soft transition metals, but can also bind to other metals.7 In an initial investigation, these first-generation catalysts have been examined in the 1,4-addition of oxindoles to 2-nitrostyrene. Despite the high modularity of the hybrid ligands, a screening of a small library of the open bimetallic complexes always provided racemic product mixtures. On the basis of spectroscopic studies, Received: July 24, 2014

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dx.doi.org/10.1021/om500762r | Organometallics XXXX, XXX, XXX−XXX

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Scheme 1. Synthesis of the Macrocyclic Ligands 4

in particular, UV-vis and X-ray crystal structure analyses,8 we hypothesized that, upon coordination of the substrate, the O bridges to the bis-NHC-ligated metal center M2 are broken, which results in a conformationally more flexible structure, in which the intermetallic distance between M1 and M2 is too large for an intramolecular cooperative effect. To avoid this unfavorable drifting of the metal centers, we were interested in the corresponding macrocyclic complexes, in which both NHC donors are linked via a diamine backbone (Figure 1, right).11 This diamine could also be chiral, thus providing an additional means for stereocontrol. In this article, we describe the synthetic access to this novel macrocyclic complex type and a preliminary investigation in asymmetric catalysis.

usually led to a matched situation, whereas the other enantiomer did not provide the targeted diimine (shown as mismatched in Table 1). A possible explanation for this matched/mismatched behavior might be significant differences in the ring strains of the corresponding macrocycles depending on the stereochemical configuration of diimine and bisimidazolium cores. In one case, the desired product was formed, but not stable in solution [(S,S)-DiPh-H4/BiPh-3], and its isolation was thus not successful. The combination of two chiral cyclohexane backbones in a macrocyclic ligand failed for both CyHex-H4 enantiomers, probably because the ring strain would be too high in both cases owing to the lower conformational flexibility of the cyclohexane as compared to an ethane or diphenyl backbone. Synthesis of Monometallic Salen Complexes. The selective installation of different metal centers in the salen N2O2 coordination sphere was investigated for BiPh-(R,R)CyHex-4 and is shown in Table 2. Coordination of Ni(II) and Pd(II) could be accomplished under conditions similar to those previously optimized for the corresponding open salen ligands.8 With NiCl2 or Pd(OAc)2, the complexes 5-M1 were formed in quantitative yields, if NaOAc was used as a base in CH2Cl2 at 35 °C (entries 1 and 2). In addition, the Zn(II) complex 5-Zn was formed in quantitative yield using ZnEt2 as a Brønsted basic metal source.13 Synthesis of Bimetallic Salen−Bis-NHC Hybrid Complexes. Coordination of Silver by the NHC Ligands. The complexes 5-M1 with M1 = PdII, NiII, or ZnII were studied in the synthesis of mixed M1/Ag complexes using a method developed by Lin et al. for NHC−Ag(I) bond formation.14 This method was previously also successfully applied to the corresponding open salen−bis-NHC−Ag(I) complexes.8 Treatment of 5-Ni with 2.0 equiv of Ag2O in 1,2-dichloroethane at 55 °C provided

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RESULTS AND DISCUSSION Ligand Synthesis. The macrocyclic bisimidazolium salen ligands were prepared via the dialdehydes 3 (Scheme 1), which are accessible via double SN2 reactions of the benzylic chloride 212 and different bisimidazoles 1. The bisimidazoles were synthesized from either (R,R)-1,2-diamino-1,2-diphenylethane, (Ra)-6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diamine, or (R,R)-1,2-diaminocyclohexane. The synthesis of the macrocyclic ligands 4 was attempted by a double condensation reaction of all three dialdehydes 3 with five different diamines: (R,R)- or (S,S)-1,2-diamino1,2-diphenylethane (DiPh-H4), (Ra)-6,6′-dimethyl-[1,1′-biphenyl]2,2′-diamine (BiPh-H4), and (R,R)- or (S,S)-1,2-diaminocyclohexane (CyHex-H4). All 15 possible combinations were investigated, but only five of them worked well (shown as matched in Table 1) and provided the corresponding macrocycles in quantitative yields. Using both possible enantiomers of the C2-symmetric diamines DiPh-H4 and CyHex-H4 for the diimine formation, one enantiomer B


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Table 1. Matched/Mismatched Situation for the Macrocyclization by Diimine Formation

Table 2. Coordination of a Metal Center by the Salen N2O2 Coordination Sphere

a

entry

M1 source

base

yield (%)a

1 2 3

NiCl2 Pd(OAc)2 ZnEt2

NaOAc NaOAc

>99 >99 >99

Yield of isolated product.

The Zn(II) complex 5-Zn strongly preferred the formation of the mono-NHC−mono-Ag complex 6-Zn, which was formed in a yield of 67% (entry 3), while the corresponding bis-Ag complex 7-Zn was not detected. In contrast, with an open hybrid ligand, the mixed silver zinc complex 9-Zn, in which both imidazolium rings were

the bis-Ag complex 7-Ni in high yield (Table 3). Applying the same conditions to the homologous Pd(II) complex 5-Pd provided a mixture of 7-Pd and the mono-NHC−mono-Ag complex 6-Pd, which could be separated by extraction with n-pentane, since only 6-Pd is nearly insoluble in n-pentane at room temperature. C


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Table 3. Synthesis of Ag−NHC Complexes

a

entry

M1

product 6-M1

yield 6-M1 (%)a

product 7-M1

yield 7-M1 (%)a

1 2 3

Ni(II) Pd(II) Zn(II)

6-Ni 6-Pd 6-Zn

99 >99 92

Yield of isolated product.

the product in nearly quantitative yield.29 A control experiment in the absence of catalyst gave only traces of product. The second investigated reaction is the Conia-ene cyclization30 of 2-cyano-hept-6-ynoate 20 to form 2-methylenecyclopentane 23 (Scheme 10).31,32 The Ni/Ag2 complex 7-Ni provided

The UV−vis spectra of these two compounds (blue curve for acetate and blue-green curve for heptafluorobutyrate) are very similar to the one obtained for 16-Ni with the chloride ligands (Figure 5). For all of these compounds with coordinating anions, a characteristic absorption maximum at around 420 nm is found. In contrast, such a maximum is not observed, if X− is a noncoordinating counterion like TfO−, ClO4−, or BARF− (red-, black-, and pink-colored curves, respectively). The complexes 17-Ni carrying the latter counterions were accessible in high yields by chloride ion exchange with the corresponding silver salts (Table 4, entries 3−5). They are all of yellow color, and their UV−vis spectra are all very similar to each other. An analogous behavior has already been found for the open salen−Ni(II)−bisNHC−Pd(II) complexes, for which structural data could also be obtained by X-ray crystal structure analyses.8 For that reason, we suggest a similar complexation behavior in the present case, namely, bridging coordination of the salen oxygen atoms, if X− is a noncoordinating anion, and no O-bridging, if X− is a coordinating anionic ligand. Preliminary Applications in Catalysis. For a preliminary investigation of the bi- and trimetallic macrocyclic complexes in catalysis, we have briefly examined two different model reactions. The first one is the direct 1,4-addition of the oxindole 19 to 2-nitrostyrene (20) using 16-Ni as (pre)catalyst (Scheme 9),

Scheme 10. Investigation of a Conia-ene Cyclization

nearly racemic product 23 in almost quantitative yield in the presence of (iPr)2NEt as a Brønsted base additive. In the absence of the base, only traces of product were found. The base in the absence of the catalyst gave no product (see the Supporting Information for more details).

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CONCLUSION In conclusion, we have described novel chiral macrocyclic hybrid ligands in which salen and two NHC donor moieties have been merged for the synthesis of bi- or trimetallic complexes. For the syntheses of these chiral ligands, a matched/mismatched behavior was found based on the configuration of the salen core and the bisimidazolium moiety. Zn(II), Ni(II), and Pd(II) were readily installed into the salen N2O2 coordination sphere, while the NHC units could be used for the coordination to Ag(I), Cu(I), Au(I), and Pd(II). Strongly puckered structures were determined by X-ray crystal structure analyses for Ni/Ag2 and Pd/Ag2 complexes, in which one of the NHC-bound Ag(I) centers is in close proximity to the salen-bound Ni(II) or Pd(II) centers and in which this Ag atom interacts with both salen O-donor atoms. Despite the strong puckering creating a chiral bimetallic cave, enantioselectivity could thus far not be achieved in the preliminary catalytic investigations.

Scheme 9. Investigation of the 1,4-Addition of Oxindoles 19 to 2-Nitrostyrene

which was selected to allow for a direct comparison with the corresponding open Ni(II)−Pd(II) catalysts.8,25−28 Like with the open bimetallic catalysts, a racemic product was formed, but the catalyst containing a Bro̷ nsted basic acetate ligand provided H


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General Procedure for the Synthesis of Monometal Complexes 5-M1/11-M1/8-Zn (GP4). To the corresponding ligand 4 or 8 (50 μmol, 1 equiv) dissolved in DCM (100 μmol in 20 mL) was added ZnEt2 (50 μL as a 1 M solution in hexanes, 50 μmol, 1 equiv), and the mixture was stirred at ambient temperature for 3 h to form the corresponding Zn complexes. For the nickel or palladium complexes, the corresponding metal salt (NiCl2 6.5 mg or Pd(OAc)2 11.2 mg, 50 μmol, 1 equiv) and NaOAc (8.2 mg, 100 μmol, 2 equiv) were added. The suspension was stirred for 24−48 h at 35 °C. The solution of the nickel complex was filtered through a pad of Celite. The solution of the palladium complex were filtered through a thin pad of Al2O3 (activity I), and the product was eluted with approximately 20 mL of DCM/MeOH (40:1). The solvent was removed by rotary evaporation. The resulting solids 5-M1/11-M1/9-Zn were dried in vacuo (0.1 mbar). General Procedure for the Synthesis of Ag−Carbene Complexes 6-M1/7-M1 and 9-Zn (GP5a). The monometal complexes 5-M1 or 8-Zn (1 equiv) prepared according to GP4 were dissolved in DCE (100 μmol in 20 mL), and Ag2O (2 equiv) was added. The suspension was stirred for 20 h at 55 °C. Subsequently, the mixture was allowed to cool to room temperature and the excess of Ag2O was removed by filtration through a pad of Celite. The solvent was removed by rotary evaporation. The resulting solids 6-M1/7-M1/9-Zn were dried in vacuo (0.1 mbar). General Procedure for the Synthesis of Cu−Carbene Complexes 10-M1/12-M1 (GP5b). The monometal complexes 5-M1 or 11-M1 (1 equiv) prepared according to GP4 were dissolved in DCE (100 μmol in 20 mL), and Cu2O (2 equiv) was added. The suspension was stirred for 20 h at 55 °C. Subsequently, the mixture was allowed to cool to room temperature and the excess of Cu2O was removed by filtration through a pad of Celite. The solvent was removed by rotary evaporation. The resulting solids 10-M1 or 12-M1 were dried in vacuo (0.1 mbar). General Procedure for the Synthesis of Macrocyclic Bimetallic Salen−NHC−Au Complexes 13-M1/14-M1 (GP6a). The Ag−carbene complexes 6-M1 or 7-M1 (1 equiv) prepared according to GP5a were dissolved in DCM (100 μmol in 20 mL), and AuCl(SMe2) (2 equiv in the cases of 7-Ni and 7-Pd and 1 equiv in the cases of 6-Ni and 6-Zn) was added. The mixture was stirred for 24 h at 35 °C. The solvent was removed under reduced pressure, and the residue was purified by flash chromatography on silica gel (eluent: DCM/MeOH, 40:1) to isolate pure 13-M1 or 14-M1. The resulting bimetallic salen NHC complexes were dried in vacuo (0.1 mbar). General Procedure for the Synthesis of Open Bimetallic Salen−bisNHC−Au Complexes 15-M1 (GP6b). The Ag−carbene complexes 9-M1 (10 μmol, 1 equiv) prepared according to GP5a were dissolved in DCM (100 μmol in 20 mL), and AuCl(SMe2) (3.7 mg, 10 μmol, 2 equiv) was added. The mixture was stirred for 24 h at 35 °C. The solvent was removed under reduced pressure, and the residue was purified by flash chromatography on silica gel (eluent: DCM/MeOH, 40:1) to isolate pure 15-M1. The resulting bimetallic salen−NHC complexes were dried in vacuo (0.1 mbar). General Procedure for the Synthesis of Macrocyclic Bimetallic Salen−NHC−Pd Complexes 16-M1 (GP6c). The Ag−carbene complexes 7-M1 (1.0 equiv) prepared according to GP5a were dissolved in DCM (100 μmol in 20 mL), and Pd2(dba)3 (0.6 equiv) was added. The mixture was stirred for 24 h at 35 °C. The solvent was removed under reduced pressure, and the residue was purified by flash chromatography on silica gel (eluent: DCM/MeOH, 40:1) to isolate pure 16-M1. The resulting bimetallic salen−NHC complexes were dried in vacuo (0.1 mbar). General Procedure for the Anion Exchange of the Salen−Ni−BisNHC−Pd Complexes (GP7). The bimetallic salen−Ni−bis-NHC−Pd complexes 16-Ni (1 equiv) prepared according to GP6c were dissolved in DCM (100 μmol in 20 mL), and the corresponding silver salt (2 equiv) was added. The suspension was stirred for 1 h (depending on the silver salt used) at room temperature until precipitation of AgCl was visible. Subsequently, the mixture was filtered through a pad of Celite and the solvent was removed under reduced pressure. Pure complex 17-Ni or 18-Ni was dried in vacuo (0.1 mbar). General Procedure for the Catalytic Synthesis of tert-Butyl-3methyl-3-(2-nitro-1-phenylethyl)-2-oxoindoline-1-carboxylate (21, GP8). trans-β-Nitrostyrene (20, 7.5 mg, 5 μmol, 1.00 equiv) and the activated catalyst (16-Ni, 17-Ni, or 18-Ni, 5 mol %, 0.05 equiv) were charged into

EXPERIMENTAL SECTION

General Considerations. All reactions were performed in dried glassware (oven at 150 °C) and, unless otherwise indicated, under nitrogen (about 1.2 bar). Liquids were added via syringe; solids were added neat against a nitrogen flow. Solvents were removed by rotary evaporation at a heating bath temperature of 40 °C and 600−10 mbar pressure. Nonvolatile compounds were dried in vacuo at 0.1 mbar. For workup procedures and flash chromatography, distilled technical grade solvents were used. Analytical grade dichloromethane was also purified by distillation. Dichloromethane (DCM), diethyl ether, THF, and toluene used for reactions were dried under nitrogen by a solvent purification system. 1,2-Dichloroethane (DCE) was stored in a crowncapped bottle under nitrogen. n-Hexane, 2-propanol (HPLC-quality), and n-pentane were used as purchased. Salen ligands,8 chloro(dimethylsulfide)gold(I),33 and substrates34 for catalysis were prepared according to literature procedures. Purchased chemicals were used without further purification. Yields refer to purified compounds and are calculated in mol % of the starting material used. Except as otherwise indicated, reactions were magnetically stirred and monitored by NMR spectroscopy or thin-layer chromatography (TLC) using silica gel plates (silica gel 60 F254). Visualization occurred by fluorescence quenching under UV light and/or by staining with KMnO4/NaOH. Purification by flash chromatography was performed on silica gel 60 (40−63 μm particle size), using a forced flow of eluent at 0.2−0.4 bar overpressure. NMR spectra were recorded at room temperature on a spectrometer operating at 500 or 300 MHz (1H), 125 or 75 MHz (13C), and 235 MHz (19F). Chemical shift δ is referred to in terms of parts per million (ppm); coupling constants J are given in Hz. The following abbreviations classify the multiplicity: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet or unresolved, br = broad signal. Infrared spectra were recorded by the IR service of the Universität Stuttgart on an FT-IR spectrometer with an ATR unit, and the signals are given by wavenumbers (cm−1). Optical rotation was measured on a polarimeter operating at the sodium D line with a 100 mm path cell length. Melting points were measured using a melting point apparatus in open glass capillaries and are uncorrected. Mass spectra were obtained from the MS service of the Universität Stuttgart. Ionization methods are stated in parentheses. Single-crystal X-ray analysis was performed by Dr. Wolfgang Frey (Universität Stuttgart). UV−vis spectra were recorded by Martina Bubrin (Universität Stuttgart, Institut für Anorganische Chemie, Kaim group). General Procedures. General Procedure for the Synthesis of Bisimidazoles 1 (GP1). A solution of glyoxal (2 equiv) and formalin (2 equiv 30% in water) in glacial acetic acid (1 mL/mmol diamine) was heated to 70 °C, and a solution of the corresponding diamine (1 equiv) and NH4Cl (2 equiv) in glacial acetic acid (1−2 mL/mmol diamine, depending on the solubility of the diamine) was added dropwise over 5 min. The mixture was stirred at 70 °C for 18 h. Subsequently, the mixture was allowed to cool to room temperature and carefully poured in a saturated Na2CO3 solution (approximately 100 mL/mmol diamine) and extracted three times with DCM. The combined organic layers were dried over Na2SO4 and filtered, and the solvent was removed under reduced pressure. The residue was purified by flash chromatography on silica gel (eluent: DCM/MeOH, 40:1 to 10:1) to isolate pure 1.35 General Procedure for the Synthesis of Dialdehydes 3 (GP2). 3(Chloromethyl)-5-(tert-butyl)-2-hydroxybenzaldehyde (2) (2 equiv) was dissolved in acetonitrile (10 mL/g aldehyde 2), and the bisimidazole (1 equiv) was added. The mixture was stirred for 24 h. Subsequently, diethyl ether (30 mL/g aldehyde) was added to cause precipitation. The mixture was filtered, and the filter cake was washed with diethyl ether. The resulting solid 3 was dried in vacuo (0.1 mbar), and no further purification was necessary. General Procedure for the Synthesis of Macrocyclic Bisimidazolium Salen Ligands 4 (GP3). A mixture of aldehyde 3 (1 equiv) in ethanol (250 mL/mmol aldehyde 3) and molecular sieves (4 Å) (10 g/mmol) was cooled to 0 °C, and a solution of the corresponding diamine (1 equiv) in EtOH (50 mL/mmol) was added dropwise over 15 min. The mixture was stirred for 20 h at ambient temperature. After filtration, EtOH was removed in vacuo. Subsequent repetitive azeotropic removal of residual EtOH with DCM gave 4 as an orange foam. I


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a flask. tBu-3-Me-2-oxoindoline-1-carboxylate (19, 24.7 mg, 10 μmol, 2.00 equiv) and HOAc (10 mol %, 0.10 equiv) were added as stem solutions in DCM. More DCM was added to get a total solvent volume of 250 μL. The flask was sealed with a plastic cap, and the reaction mixture was stirred for 20 h at room temperature. Afterward, the catalyst was removed by filtration through a small pad of silica and the product was eluted with PE/EE (1:1, 10 mL). General Procedure for the Catalytic Synthesis of Ethyl-1-acetyl-2methylenecyclopentane-1-carboxylate (23, GP9). To the corresponding catalyst (7-Ni, 13-Ni, 14-Ni, 15-Ni, 14-Zn, or 14-Pd, 5 mol %, 0.05 equiv) were added ethyl 2-acetylhept-6-ynoate (22, 9.0 mg, 5 μmol, 1.00 equiv) and isopropanol (3.0 mg, 4 μL, 1.00 equiv) as stem solution in DCM. More DCM was added to get a total solvent volume of 250 μL. The flask was sealed with a plastic cap, and the reaction mixture was stirred for 20 h at room temperature. Afterward, the catalyst was removed by filtration through a small pad of silica and the product was eluted with PE/EE (1:1, 10 mL). Synthesis of Bisimidazoles. (Ra)-1,1′-(6,6′-Dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazole) (BiPh-1). Bisimidazole BiPh-1 was prepared according to GP1. A glyoxal solution (40 wt % in water, 683.5 mg, 538 μL, 4.71 mmol, 2.00 equiv) and formalin (404.2 mg, 371 μL, 4.71 mmol, 2.00 equiv) were dissolved in HOAc (1.25 mL) and treated with a solution of NH4Cl (363.1 mg, 4.71 mmol, 2.00 equiv) and (Ra)-diamino-1,1′-dimethylbiphenyl (500.0 mg, 2.36 mmol, 1.00 equiv) in HOAc (2.50 mL). Compound BiPh-1 was isolated as a light brown foam (587.10 mg, 1.86 mmol, 79%). C20H18N4, MW: 314.38 g·mol−1. Mp: 50.3−54.3 °C. [α]20 D = +38.0 (c = 0.1 g·dL−1, CH2Cl2). HRMS (ESI) m/e: Calcd for [M + H]+ C20H19ClN4: 315.1604. Found: 315.1600. The racemic compound is literature known, and further analytical data of BiPh-1 are in agreement with the literature.34 (1R,2R)-1,2-Di(1H-imidazol-1-yl)cyclohexane (CyHex-1). Bisimidazole CyHex-1 was prepared according to GP1. A glyoxal solution (40 wt % in water, 254.1 mg, 200 μL, 1.75 mmol, 2 equiv) and formalin (150.3 mg, 138 μL, 1.75 mmol, 2 equiv) were dissolved in HOAc (0.5 mL) and treated with a solution of NH4Cl (135.0 mg, 1.75 mmol, 2 equiv) and (1R,2R)-diaminocyclohexane (100.0 mg, 0.88 mmol, 1 equiv) in HOAc (0.3 mL). Compound CyHex-1 was filtered through a short pad of silica (eluent: DCM/MeOH, 10:1) and used without further purification for the next step due to its instability toward silica. (1R,2R)-1,2-Di(1H-imidazol-1-yl)-1,2-diphenylethane (DiPh-1). Bisimidazole DiPh-1 was prepared according to GP1. A glyoxal solution (40 wt % in water, 273.4 mg, 215 μL, 1.88 mmol, 2 equiv) and formalin (161.7 mg, 148 μL, 1.88 mmol, 2 equiv) were dissolved in HOAc (0.5 mL) and treated with a solution of NH4Cl (145.2 mg, 1.88 mmol, 2 equiv) and (1R,2R)-diphenylethylenediamine (200.0 mg, 0.94 mmol, 1 equiv) in HOAc (1.0 mL). Compound DiPh-1 was isolated as a light brown foam (98.9 mg, 0.31 mmol, 33%). The enantiopure compound is literature known, and analytical data are in agreement with the literature.36 Synthesis of Dialdehydes. (Ra)-1,1′-(6,6′-Dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(3-(5-(tert-butyl)-3-formyl-2-hydroxybenzyl)-1H-imidazol-3-ium)dichloride (BiPh-3). Bisaldehyde BiPh-3 was prepared according to GP2. 3-(Chloromethyl)-5-(tert-butyl)-2-hydroxybenzaldehyde (2) (0.17 g, 0.74 mmol, 2 equiv) was treated with (Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazole) BiPh-H4 (0.12 g, 0.37 mmol, 1 equiv). Compound BiPh-3 (0.26 g, 0.34 mmol, 92%) was isolated as a beige solid. C44H48Cl2N4O4, MW: 767.78 g·mol−1. Mp: 172.9−177.6 °C. [α]20 D = +66.0 (c = 0.1 g·dL−1, CH2Cl2). 1H NMR (300 MHz, CDCl3, 21 °C): δ = 11.10 (s, 2 H, CHO), 10.56 (s, 2 H, CArOH), 9.92 (s, 2 H, NCHNImid), 8.22 (d, J = 2.5, 2 H, CHAr), 7.58 (d, J = 2.5, 2 H, CHAr), 7.50−7.46 (m, 4 H, CHBiPh), 7.44 (s, 2 H, NCHImid), 7.39−7.38 (m, 2 H, CHBiPh), 6.80 (s, 2 H, NCHImid), 5.98 (d, J = 14.2, 2 H, CArCH2), 5.89 (d, J = 14.2, 2 H, CArCH2), 2.22 (s, 6 H, C BiPhCH3), 1.33 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 196.3, 157.7, 144.0, 139.9, 137.6, 137.5, 133.01, 132.99, 131.2, 130.9, 129.4, 124.7, 124.0, 121.41, 121.37, 120.5, 49.2, 34.4, 31.3 (3 C), 20.2. IR (solid): ṽ = 2958, 1649, 1543, 1463, 1364, 1275, 1216, 1101, 1007, 788, 732. HRMS (ESI) m/e: Calcd for [M − 2Cl]2+C44H48N4O4: 348.1832. Found: 348.1811.

1,1′-((1R,2R)-Cyclohexane-1,2-diyl)bis(3-(5-(tert-butyl)-3-formyl2-hydroxybenzyl)-1H-imidazol-3-ium)dichloride (CyHex-3). Bisaldehyde CyHex-3 was prepared according to GP2. 3-(Chloromethyl)-5(tert-butyl)-2-hydroxybenzaldehyde (2) (0.41 g, 1.83 mmol, 2 equiv) was treated with (1R,2R)-1,2-di(1H-imidazol-1-yl)cyclohexane CyHexH4 (0.2 g, 0.91 mmol, 1 equiv). Compound CyHex-3 (0.41 g, 0.60 mmol, 66%) was isolated as a beige solid. C36H46Cl2N4O4, MW: 669.68 g·mol−1. Mp: 182.0−184.0 °C −1 1 (decomp.). [α]20 D = −35.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3, 21 °C): δ = 11.20 (s, 2 H, CHO), 10.69 (s, 2 H, CArOH), 9.88 (s, 2 H, NCHNImid), 8.51 (s, 2 H, NCHImid), 7.90 (d, J = 2.5, 2 H, CHAr), 7.60 (d, J = 2.6, 2 H, CHAr), 7.15 (s, 2 H, NCHImid), 5.89−5.87 (m, 2 H, N(CH)Ring), 5.43 (d, J = 14.4, 2 H, CArCH2), 5.34 (d, J = 14.4, 2 H, CArCH2), 2.28−2.26 (m, 2 H, CH2)Ring), 2.11−2.09 (m, 2 H, CH2)Ring), 1.93−1.91 (m, 2 H, CH2)Ring), 1.76−1.72 (m, 2 H, CH2)Ring), 1.33 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 196.7, 157.3, 144.0, 136.7, 136.3, 131.7, 123.2, 121.6, 121.0, 120.4, 62.0, 48.4, 34.4, 33.7, 31.3 (3 C), 24.0. IR (solid): ṽ = 3417, 2953, 2863, 1655, 1616, 1557, 1471, 1446, 1382, 1366, 1276, 1216, 1173, 1008, 927, 879, 847, 829, 742. HRMS (ESI) m/e: Calcd for [M − 2Cl]2+C36H46N4O4: 299.1754. Found: 299.1732. 1,1′-((1R,2R)-1,2-Diphenylethane-1,2-diyl)bis(3-(5-(tert-butyl)-3formyl-2-hydroxybenzyl)-1H-imidazol-3-ium)dichloride (DiPh-3). Bisaldehyde DiPh-3 was prepared according to GP2. 3-(Chloromethyl)-5-(tert-butyl)-2-hydroxybenzaldehyde (2) (0.09 g, 0.40 mmol, 2 equiv) was treated with (1R,2R)-1,2-di(1H-imidazol-1-yl)-1,2diphenylethane DiPh-H4 (0.06 g, 0.20 mmol, 1 equiv). Compound DiPh-3 (0.10 g, 0.13 mmol, 66%) was isolated as a white solid. C44H48Cl2N4O4, MW: 767.78 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −38.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3, 21 °C): δ = 11.27 (s, 2 H, CHO), 11.16 (br, 2 H, CArOH), 9.86 (s, 2 H, NCHNImid), 8.99 (s, 2 H, NCHImid), 8.40 (s, 2 H, CPhCHN), 7.96−7.94 (m, 2 H, CHPh), 7.77 (d, J = 2.5, 2 H, CHAr), 7.59 (d, J = 2.5, 2 H, CHAr), 7.24−7.16 (m, 4 H, CHPh), 7.06 (t, J = 1.5, 2 H, NCHImid), 5.32 (d, J = 13.9, 2 H, CArCH2), 5.28 (d, J = 13.9, 2 H, CArCH2), 1.32 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 196.7, 157.3, 137.1, 135.8, 134.1, 138.1, 129.7, 129.5, 128.7, 123.8, 124.3, 120.7, 120.3, 64.4, 48.4, 34.4, 31.3 (3 C). IR (solid): ṽ = 2953, 2865, 1650, 1619, 1545, 1481, 1461, 1442, 1275, 1219, 1148, 1007, 744, 723, 707, 661, 629. HRMS (ESI) m/e: Calcd for [M − 2Cl − H + 2OCH3]+C46H53N4O6: 757.3948. Found: 757.3960. Synthesis of Macrocyclic Ligands (4). (1R,2R)-(−)-N,N′-Bis(3tert-butyl-5-diyl-1-ylmethyl-salicyliden)-[(Ra)-1,1′-(6,6′-dimethyl[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-3-ium)]-1,2-cyclohexan-diamin-dichloride (BiPh-(R,R)-CyHex-4). Salen ligand BiPh-(R,R)CyHex-4 was prepared according to GP3. Bisaldehyde BiPh-3 (100.0 mg, 25 μmol, 1 equiv) was treated with (1R,2R)-diaminocyclohexane ((R,R)-CyHex-H4, 14.9 mg, 25 μmol, 1 equiv). Compound BiPh-(R,R)CyHex-4 (110.20 mg, 25 μmol, 100%) was isolated as a yellow solid. C50H58Cl2N6O2, MW: 845.94 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = +24.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CDCl3): δ = 14.42 (br, 2 H, CArOH), 8.60 (s, 2 H, NCHNImid), 8.54 (s, 2 H, N CH), 8.35 (d, J = 2.5, 2 H, CHAr), 7.41 (d, J = 2.5, 2 H, CHAr), 7.31 (d, J = 7.8, 2 H, CHBiPh), 7.21 (s, 2 H, NCHImid), 7.06 (t, J = 7.8, 2 H, CHBiPh), 6.96 (d, J = 7.8, 2 H, CHBiPh), 6.83 (s, 2 H, NCHImid), 6.04 (d, J = 13.5, 2 H, CArCH2), 5.05 (d, J = 13.5, 2 H, CArCH2), 3.51−3.48 (m, 2 H, N(CH)Ring), 2.30 (s, 6 H, CBiPhCH3), 2.27−2.23 (m, 2 H, (CH2)Ring), 2.04−2.00 (m, 2 H, (CH2)Ring), 1.69−1.59 (m, 2 H, (CH2)Ring), 1.55− 1.49 (m, 2 H, (CH2)Ring), 1.38 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 163.8, 159.1, 142.1, 140.6, 136.4, 134.4, 132.9, 132.3, 130.4, 129.9, 129.9, 124.1, 123.3, 121.3, 121.0, 117.9, 69.5, 49.3, 34.5, 31.7 (3 C), 31.2, 24.2, 20.3. IR (solid): ṽ = 2951, 2862, 1630, 1542, 1480, 1463, 1225, 1103, 925, 789, 726, 638. HRMS (ESI) m/e: Calcd for [M − 2Cl]2+C50H58ClN6O2: 387.2305. Found: 387.2265. (1R,2R)-(−)-N,N′-Bis(3-tert-butyl-5-diyl-1-ylmethyl-salicyliden)[(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-3ium)]-1,2-diphenylethan-diamin-dichloride (BiPh-(S,S)-DiPh-4). Salen ligand BiPh-(S,S)-DiPh-4 was prepared according to GP3. Bisaldehyde DiPh-3 (19.2 mg, 25 μmol, 1 equiv) was treated with (1S,2S)-diphenylethylenediamine ((S,S)-DiPh-H4, 5.3 mg, 25 μmol, J


Organometallics

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1 equiv). Compound BiPh-(S,S)-DiPh-4 (23.6 mg, 25 μmol, 100%) was isolated as a yellow solid. C58H60Cl2N6O2, MW: 944.04 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = +107.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 14.55 (br, 2 H, CArOH), 8.91 (s, 2 H, NCHNImid), 8.33 (s, 2 H, N CH), 8.32 (d, J = 2.5, 2 H, CHAr), 7.43−7.04 (m, 2 H, CHAr, 6 H, CHBiPh, 4 H, NCHImid, 10 H, CHPh), 6.00 (d, J = 13.4, 2 H, CArCH2), 5.28 (d, J = 13.4, 2 H, CArCH2), 5.04 (s, 2 H, CPhCHN), 2.32 (s, 6 H, CBiPhCH3), 1.35 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 167.0, 158.9, 141.2, 139.2, 137.3, 134.6, 133.4, 133.0, 130.6, 130.4, 130.1, 129.2 (2 C), 128.6, 128.5 (2 C), 124.6, 123.7, 122.0, 121.5, 118.4, 77.6, 49.8, 34.7, 31.8 (3 C), 20.5. Ligand decomposed during measurement of carbon NMR. IR (solid): ṽ = 2952, 1628, 1600, 1541, 1481, 1463, 1225, 1099, 1041, 1018, 787, 750, 700, 634. HRMS (ESI) m/e: Calcd for [M − Cl]+ C58H60ClN6O2: 907.4461. Found: 907.4465. (R)-(−)-N,N′-Bis(3-tert-butyl-5-diyl-1-ylmethyl-salicyliden)-[(Ra)1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-3ium)]-diamino-1,1′-dimethylbiphenyl-dichloride (BiPh-(Ra)-BiPh-4). Salen ligand BiPh-(Ra)-BiPh-4 was prepared according to GP3. Bisaldehyde BiPh-3 (19.2 mg, 25 μmol, 1 equiv) was treated with (Ra)-diamino-1,1′-dimethylbiphenyl ((Ra)-BiPh-H4, 5.3 mg, 25 μmol, 1 equiv). Compound BiPh-(Ra)-BiPh-4 (24.0 mg, 25 μmol, 100%) was isolated as a yellow solid. C59H64Cl2N6O2, MW: 960.08 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −227.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CDCl3): δ = 13.63 (br, 2 H, CArOH), 8.85 (s, 2 H, NCHNImid), 8.74 (s, 2 H, N CH), 8.19 (d, J = 2.5, 2 H, CHAr), 7.56 (s, 2 H, NCHImid), 7.43 (d, J = 2.5, 2 H, CHAr), 7.37 (d, J = 8.3, 2 H, CHBiPh), 7.35 (t, J = 7.3, 2 H, CHBiPh), 7.22 (d, J = 7.3, 4 H, CHBiPh), 7.12 (t, J = 8.3, 2 H, CHBiPh), 6.95 (d, J = 8.3, 2 H, CHBiPh), 6.16 (s, 2 H, NCHImid), 5.95 (d, J = 13.4, 2 H, CArCH2), 5.08 (d, J = 13.4, 2 H, CArCH2), 2.29 (s, 6 H, CBiPhCH3), 1.96 (s, 6 H, CBiPhCH3), 1.35 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 160.8, 157.2, 144.5, 142.9, 141.2, 138.5, 136.4, 134.2, 133.2, 133.1, 132.2, 130.5, 130.1, 129.7, 129.54, 129.47, 128.9, 128.8, 125.0, 122.8, 121.8, 121.7, 120.2, 118.6, 118.5, 115.6, 48.8, 34.5, 31.6 (3 C), 20.4, 19.9. IR (solid): ṽ = 3339, 2954, 1619, 1597, 1567, 1542, 1461, 1364, 1278, 1215, 1103, 1016, 785, 737, 635. HRMS (ESI) m/e: Calcd for [M − 2Cl − CH4]2+ C58H60N6O2: 436.2383. Found: 436.2372. (1R,2R)-(−)-N,N′-Bis(3-tert-butyl-5-diyl-1-ylmethyl-salicyliden)[(1R,2R)-1,2-di(1H-imidazol-3-ium)cyclohexane]-1,2-diphenylethan-diamin-dichloride (CyHex-(R,R)-DiPh-4). Salen ligand CyHex(R,R)-DiPh-4 was prepared according to GP3. Bisaldehyde CyHex-3 (16.7 mg, 25 μmol, 1 equiv) was treated with (1R,2R)-diphenylethylendiamine ((R,R)-DiPh-H4, 5.3 mg, 25 μmol, 1 equiv). Compound CyHex-(R,R)-DiPh-4 (21.1 mg, 25 μmol, 100%) was isolated as a yellow solid. C50H58Cl2N6O2, MW: 845.94 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −97.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 14.00 (br, 2 H, CArOH), 10.75 (s, 2 H, NCHNImid), 8.53 (s, 2 H, NCHImid), 8.06 (s, 2 H, NCH), 7.47 (d, J = 2.5, 2 H, CHAr), 7.38−7.22 (m, 2 H, CHAr, 10 H, CHPh), 6.75 (s, 2 H, NCHImid), 6.29−6.26 (m, 2 H, N(CH)Ring), 5.41 (d, J = 14.0, 2 H, CArCH2), 5.32 (d, J = 14.0, 2 H, CArCH2), 4.93 (s, 2 H, CPhCHN), 2.37−2.33 (m, 2 H, (CH2)Ring), 2.24− 2.21 (m, 2 H, (CH2)Ring), 2.01−1.98 (m, 2 H, (CH2)Ring), 1.84−1.77 (m, 2 H, (CH2)Ring), 1.27 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 165.8, 157.5, 141.2, 138.8, 135.2, 131.9, 129.8, 127.9 (2 C), 127.0, 126.5 (2 C), 121.4, 119.5, 117.6, 116.9, 78.0, 60.9, 48.8, 33.2, 32.9, 30.3 (3 C), 23.5. IR (solid): ṽ = 2954, 1629, 1600, 1552, 1480, 1451, 1364, 1279, 1225, 1157, 1016, 750, 700, 636. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H58ClN6O2: 809.4304. Found: 809.4284. (1R,2R)-(−)-N,N′-Bis(3-tert-butyl-5-diyl-1-ylmethyl-salicyliden)[(1R,2R)-1,2-di(1H-imidazol-3-ium)-1,2-diphenylethane]-1,2-cyclohexan-diamin-dichloride (DiPh-(R,R)-CyHex-4). Salen ligand DiPh(R,R)-CyHex-4 was prepared according to GP3. Bisaldehyde DiPh-3 (19.2 mg, 25 μmol, 1 equiv) was treated with (1S,2S)-diaminocyclohexane ((S,S)-CyHex-H4, 2.9 mg, 25 μmol, 1 equiv). Compound DiPh(R,R)-CyHex-4 (21.1 mg, 25 μmol, 100%) was isolated as a yellow solid. C50H58Cl2N6O2, MW: 845.94 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = +41.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 13.82 (br, 2 H, CArOH), 10.97 (s, 2 H, NCHNImid), 8.54 (s, 2 H,

CPhCHN), 8.38 (s, 2 H, NCH), 8.19 (d, J = 7.0, 4 H, CHPh), 7.96 (br, 2 H, NCHImid), 7.38 (d, J = 2.5, 2 H, CHAr), 7.34−7.17 (m, 2 H, CHAr, 6 H, CHPh), 6.71 (br, 2 H, NCHImid), 5.17 (d, J = 13.5, 2 H, CArCH2), 4.56 (d, J = 13.5, 2 H, CArCH2), 3.45−3.44 (m, 2 H, N(CH)Ring), 2.09−2.05 (m, 2 H, (CH2)Ring), 1.98−1.95 (m, 2 H, (CH2)Ring), 1.74−1.70 (m, 2 H, (CH2)Ring), 1.55−1.49 (m, 2 H, (CH2)Ring), 1.41 (s, 18 H, C(CH3)3). 13 C NMR (125 MHz, CD2Cl2): δ = 164.6, 158.1, 142.3, 136.9, 134.7, 133.4, 130.4, 130.0, 129.83 (2 C), 129.79 (2 C), 122.7, 121.2, 118.7, 72.2, 65.2, 49.4, 34.6, 31.7 (3 C), 31.5 24.9. IR (solid): ṽ = 2952, 1631, 1481, 1461, 1444, 1364, 1283, 1226, 1145, 1013, 749, 729, 710, 696, 663, 637. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H58ClN6O2: 809.4304. Found: 809.4305. (1R,2R)-(−)-N,N′-Bis(3-tert-butyl-5-diyl-1-ylmethyl-salicyliden)[(1R,2R)-1,2-di(1H-imidazol-3-ium)-1,2-diphenylethane]-1,2diphenylethan-diamin-dichloride (DiPh-(S,S)-DiPh-4). Salen ligand DiPh-(S,S)-DiPh-4 was prepared according to GP3. Bisaldehyde DiPh-3 (19.2 mg, 25 μmol, 1 equiv) was treated with (1S,2S)diphenylethylenediamine ((S,S)-DiPh-H4, 5.3 mg, 25 μmol, 1 equiv). Compound DiPh-(S,S)-DiPh-4 (23.6 mg, 25 μmol, 100%) was isolated as a yellow solid. C58H60Cl2N6O2, MW: 944.04 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −82.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 13.99 (br, 2 H, CArOH), 11.00 (s, 2 H, NCHNImid), 9.07 (s, 2 H, NCHImid), 8.83 (s, 2 H, CPhCHN), 8.14 (d, J = 7.3, 4 H, CHPh), 8.10 (s, 2 H, NCH), 7.38 (d, J = 2.5, 2 H, CHAr), 7.34−7.24 (m, 2 H, CHAr, 14 H, CHPh), 6.70 (s, 2 H, NCHImid), 5.34 (d, J = 13.3, 2 H, CArCH2), 5.29 (d, J = 13.3, 2 H, CArCH2), 4.94 (s, 2 H, CPhCHN), 1.25 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 165.9, 157.4, 141.3, 138.9, 135.2, 134.3, 134.8, 129.9, 128.7, 128.6 (2 C), 128.3 (2 C), 127.9 (2 C), 127.0, 126.6 (2 C), 121.5, 119.8, 117.7, 116.6, 77.8, 62.8, 48.8, 3.2, 30.2 (3 C). IR (solid): ṽ = 2955, 2922, 1630, 1601, 1480, 1451, 1364, 1280, 1225, 1148, 1044, 1016, 954, 749, 727, 698, 661, 638. HRMS (ESI) m/e: Calcd for [M − Cl]+ C58H60ClN6O2: 907.4461. Found: 907.4468. Synthesis of Monometal Complexes 5-M1/8-Zn. {[1,1′-[(1R,2R)1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxyκO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-3-ium)](2−)]nickel(II)}dichloride (5-Ni). Complex 5-Ni was prepared according to GP4. Ligand BiPh-(R,R)CyHex-4 (42.2 mg, 50 μmol, 1 equiv) was used, and the mixture was stirred for 48 h at 35 °C. Compound 5-Ni (45.1 mg, 50 μmol, 100%) was isolated as a red solid. C50H56Cl2N6NiO2, MW: 902.62 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −300.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CDCl3): δ = 9.41 (s, 1 H, NCHNImid), 8.82 (s, 1 H, s, 1 H, NCHNImid), 7.79−7.40 (m, 2 H, NCH, 2 H, CHAr, 6 H, CHBiPh, 2 H, NCHImid), 7.18 (d, J = 2.5, 2 H, CHAr), 7.02 (s, 1 H, NCHImid), 5.76 (d, J = 14.2, 1 H, CArCH2), 5.71 (d, J = 14.2, 1 H, CArCH2), 5.22 (d, J = 14.2, 1 H, CArCH2), 4.94 (d, J = 14.2, 1 H, CArCH2), 3.50−3.43 (m, 1 H, N(CH)Ring), 3.06−3.00 (m, 1 H, N(CH)Ring), 2.74−2.72 (m, 1 H, (CH2)Ring), 2.51−2.48 (m, 1 H, (CH2)Ring), 2.26 (s, 3 H, CBiPhCH3), 2.22 (s, 3 H, CBiPhCH3), 1.96−1.93 (m, 2 H, (CH2)Ring), 1.51−1.42 (m, 2 H, (CH2)Ring), 1.37−1.31 (m, 2 H, (CH2)Ring), 1.30 (s, 9 H, C(CH3)3), 1.24 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 160.6, 159.4 (2 C), 158.4, 140.4, 139.4, 138.7, 138.5, 136.7, 136.2, 135.5, 1335, 133.4, 132.9, 132.7, 132.4, 132.2, 132.0, 131.3, 130.5, 129.4, 129.2, 125.0, 124.3, 124.1, 124.0, 123.5, 121.6, 121.4, 120.3, 120.03, 120.00, 70.3, 70.1, 52.6, 51.0, 33.98, 33.86, 31.5 (3 C), 31.4 (3 C), 29.3, 29.0, 24.4, 24.2. IR (solid): ṽ = 2950, 1620, 1545, 1459, 1391, 1363, 1324, 1275, 1255, 1224, 1101, 1052, 835, 794, 735, 649, 591. HRMS (ESI) m/e: Calcd for [M − 2Cl]2+ C50H56N6NiO2: 415.1904. Found: 415.1920. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-3-ium)](2-)]palladium(II)}dichloride (5-Pd). Complex 5-Pd was prepared according to GP4. Ligand BiPh-(R,R)-CyHex-4 (42.2 mg, 50 μmol, 1 equiv) was used, and the mixture was stirred for 24 h at 35 °C. Compound 5-Pd (47.0 mg, 50 μmol, 100%) was isolated as a yellow solid. C50H56Cl2N6O2Pd, MW: 950.34 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −237.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CDCl3): δ = 9.89 (s, 1 H, NCHNImid), 9.04 (s, 1 H, NCHNImid), 8.07 (s, 1 H, N CH), 8.00 (s, 1 H, NCH), 7.89 (d, J = 2.5, 2 H, CHAr), 7.53 (s, 1 H, K


Organometallics

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C50H54Ag2Cl2N6NiO2, MW: 1116.34 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −191.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 7.51−7.33 (m, 2 H, NCH, 1 H, CHAr, 6 H, CHBiPh), 7.23 (d, J = 2.5, 1 H, CHAr), 7.16 (d, J = 2.5, 1 H, CHAr), 7.13 (d, J = 2.5, 1 H, CHAr), 7.01 (t, J = 1.9, 1 H, NCHImid), 6.40 (t, J = 1.9, 1 H, NCHImid), 6.26 (t, J = 1.9, 1 H, NCHImid), 6.24 (t, J = 1.9, 1 H, NCHImid), 5.97 (d, J = 13.4, 1 H, CArCH2), 5.93 (d, J = 11.7, 1 H, CArCH2), 4.51 (d, J = 14.3, 1 H, CArCH2), 4.50 (d, J = 11.7, 1 H, CArCH2), 3.39−3.31 (m, 1 H, N(CH)Ring), 3.11−3.02 (m, 1 H, N(CH)Ring), 2.54−2.49 (m, 1 H, (CH2)Ring), 2.44−2.40 (m, 1 H, (CH2)Ring), 2.19 (s, 3 H, CBiPhCH3), 2.15 (s, 3 H, CBiPhCH3), 1.95−1.87 (m, 2 H, (CH2)Ring), 1.44−1.28 (m, 4 H, (CH2)Ring), 1.23 (s, 9 H, C(CH3)3), 1.19 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 161.4, 160.5, 157.6 (2 C), 139.5, 139.0, 138.6, 138.4, 137.3, 136.7, 135.2, 132.8, 131.9, 131.3 (2 C), 129.4, 127.6, 127.0, 126.1, 123.8, 123.7, 121.8, 121.4, 120.8, 120.1, 119.42, 119.37, 71.1, 69.3, 51.8, 50.1, 34.0, 33.9, 31.54 (3 C), 31.47 (3 C), 28.91, 28.88, 24.9, 24.7, 20.2, 20.0. IR (solid): ṽ = 2948, 2863, 1619, 1548, 1459, 1409, 1389, 1363, 1339, 1272, 1243, 1222, 1123, 1104, 1049, 837, 793, 738. HRMS (ESI) m/e: Calcd for [M − (Cl − Ag − Cl)]+ C50H54AgN6NiO2: 937.2700. Found: 937.2745. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]palladium(II)}disilver(I)dichloride (7-Pd). Complex 7-Pd was prepared according to GP5a. Monopalladium complex 5-Pd (47.0 mg, 50 μmol, 1 equiv) and Ag2O (23.4 mg, 100 μmol, 2 equiv) were used. Ag−carbene complex 7-Pd (18.7 mg, 18 μmol, 35%) was isolated as a yellow solid. C50H54Ag2Cl2N6O2Pd, MW: 1164.06 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −231.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 7.81 (s, 1 H, NCH), 7.78 (s, 1 H, NCH), 7.47−7.29 (m, 3 H, CHAr, 6 H, CHBiPh), 7.26 (d, J = 2.5, 1 H, CHAr), 6.98 (t, J = 1.9, 1 H, NCHImid), 6.49 (t, J = 1.9, 1 H, NCHImid), 6.36 (t, J = 1.9, 1 H, NCHImid), 6.35 (t, J = 1.9, 1 H, NCHImid), 6.14 (d, J = 13.4, 1 H, CArCH2), 5.95 (d, J = 13.4, 1 H, CArCH2), 4.44 (d, J = 13.4, 1 H, CArCH2), 4.41 (d, J = 13.4, 1 H, CArCH2), 3.58−3.55 (m, 1 H, N(CH)Ring), 3.50−3.46 (m, 1 H, N(CH)Ring), 2.64−2.42 (m, 1 H, (CH2)Ring), 2.56−2.53 (m, 1 H, (CH2)Ring), 2.19 (s, 3 H, CBiPhCH3), 2.18 (s, 3 H, CBiPhCH3), 1.93−1.86 (m, 2 H, (CH2)Ring), 1.59−1.55 (m, 2 H, (CH2)Ring), 1.39−1.32 (m, 2 H, (CH2)Ring), 1.31 (s, 9 H, C(CH3)3), 1.23 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 162.3, 161.8, 155.8, 155.7, 139.5, 139.1, 138.8, 137.1, 136.5, 136.0, 133.4, 133.2, 132.0, 131.6, 131.3, 131.2, 131.1, 129.6, 129.4, 128.0, 127.3, 126.4, 123.71, 123.66, 122.9, 122.5, 121.9, 120.6, 120.5, 120.24, 120.19, 119.40, 119.35, 73.5, 71.4, 53.1, 51.0, 34.0, 33.9, 31.6 (3 C), 31.5 (3 C), 28.9, 28.6, 25.0, 24.9. IR (solid): ṽ = 2951, 2924, 2856, 1624, 1545, 1460, 1389, 1364, 1271, 1220, 1202, 1122, 1101, 1041, 793, 739, 715, 562. HRMS (ESI) m/e: Calcd for [M − Ag − Cl + H]+ C50H55AgClN6O2Pd: 1021.2164. Found: 1021.2162. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2-)]palladium(II)}silver(I)dichloride (6-Pd). Complex 6Pd was prepared according to GP5a. Monopalladium complex 5-Pd (47.0 mg, 50 μmol, 1 equiv) and Ag2O (23.4 mg, 100 μmol, 2 equiv) were used. Ag−carbene complex 6-Pd (33.2 mg, 32 μmol, 65%) was isolated as a yellow solid. C50H55AgCl2N6O2Pd, MW: 1057.20 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −110.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 9.24 (t, J = 1.3, 1 H, NCHNImid), 7.96 (d, J = 1.5, 1 H, CHAr), 7.86 (d, J = 1.5, 1 H, CHAr), 7.47−7.29 (m, 2 H, NCH, 6 H, CHBiPh), 7.21 (d, J = 1.5, 1 H, CHAr), 7.18 (d, J = 1.5, 1 H, CHAr), 7.25 (t, J = 1.9, 1 H, NCHImid), 6.54 (t, J = 1.9, 1 H, NCHImid), 6.34 (t, J = 1.9, 1 H, NCHImid), 6.31 (t, J = 1.9, 1 H, NCHImid), 6.06 (d, J = 14.3, 1 H, CArCH2), 5.93 (d, J = 12.9, 1 H, CArCH2), 4.79 (d, J = 14.3, 1 H, CArCH2), 4.58 (d, J = 12.9, 1 H, CArCH2), 3.64−3.61 (m, 1 H, N(CH)Ring), 3.45−3.39 (m, 1 H, N(CH)Ring), 2.73−2.68 (m, 2 H, (CH2)Ring), 2.33 (s, 3 H, CBiPhCH3), 2.24 (s, 3 H, CBiPhCH3), 2.02−1.98 (m, 2 H, (CH2)Ring), 1.64−1.53 (m, 2 H, (CH2)Ring), 1.38−1.33 (m, 2 H, (CH2)Ring), 1.31 (s, 9 H, C(CH3)3), 1.24 (s, 9 H, C(CH3)3). 13C NMR

NCHImid), 7.52−7.28 (m, 2 H, CHAr, 6 H, CHBiPh, 2 H, NCHImid), 7.11 (s, 1 H, NCHImid), 6.14 (d, J = 13.4, 1 H, CArCH2), 6.02 (d, J = 13.4, 1 H, CArCH2), 4.99 (d, J = 13.4, 1 H, CArCH2), 4.91 (d, J = 13.4, 1 H, CArCH2), 3.70−3.64 (m, 1 H, N(CH)Ring), 3.46−3.38 (m, 1 H, N(CH)Ring), 2.90−2.78 (m, 2 H, (CH2)Ring), 2.27 (s, 3 H, CBiPhCH3), 2.23 (s, 3 H, CBiPhCH3), 2.00−1.89 (m, 2 H, (CH2)Ring), 1.66−1.55 (m, 2 H, (CH2)Ring), 1.50−1.40 (m, 2 H, (CH2)Ring), 1.34 (s, 9 H, C(CH3)3), 1.25 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 174.93, 174.87, 161.8, 160.3, 157.1 (2 C), 140.5, 139.2, 138.3, 137.2, 136.4, 135.6, 134.0, 133.9, 133.1, 132.9, 132.5, 132.4, 131.3, 131.2, 129.7, 129.5, 124.70, 124.65, 124.4, 124.2, 123.6, 122.0, 121.9, 121.3, 121.2, 120.7, 72.4 (2 C), 53.9, 51.6, 33.9 (2 C), 31.53 (3 C), 31.48 (3 C), 29.1, 28.9, 24.44, 24.38, 20.1, 20.0. IR (solid): ṽ = 2949, 1706, 1622, 1541, 1456, 1364, 1320, 1218, 1098, 1041, 866, 836, 821, 794, 773, 759, 736, 714, 684, 659, 639, 596, 570, 546. HRMS (ESI) m/e: Calcd for [M − 2Cl]2+ C50H56N6O2Pd: 439.1753. Found: 439.1743. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-3-ium)](2-)]zinc(II)}dichloride (5-Zn). Complex 5-Zn was prepared according to GP4. Ligand BiPh-(R,R)-CyHex-4 (42.2 mg, 50 μmol, 1 equiv) was used, and the mixture was stirred for 3 h at room temperature. Compound 5-Zn (45.5 mg, 50 μmol, 100%) was isolated as a pale yellow solid. C50H56Cl2N6O2Zn, MW: 909.30 g·mol−1. Mp: >200 °C (decomp.). −1 1 [α]20 D = −274.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 9.47 (s, 1 H, NCHNImid), 9.31 (s, 1 H, NCHNImid), 8.16 (s, 1 H, N CH), 7.50−7.12 (m, 4 H, CHAr, 6 H, CHBiPh, 2 H, NCHImid), 6.22 (s, 1 H, NCHImid), 5.78 (b, 2 H, CArCH2), 4.92 (b, 2 H, CArCH2), 4.74−4.69 (m, 2 H, N(CH)Ring), 2.52−2.46 (m, 1 H, (CH2)Ring), 2.40−2.33 (m, 1 H, (CH2)Ring), 2.15 (s, 3 H, CBiPhCH3), 2.10 (s, 3 H, CBiPhCH3), 2.01− 1.93 (m, 2 H, (CH2)Ring), 1.44−1.93 (m, 4 H, (CH2)Ring), 1.26 (s, 9 H, C(CH3)3), 1.20 (s, 9 H, C(CH3)3). 1H NMR - broad signals, allocated with HSQC. 13C NMR (125 MHz, CDCl3): δ = 175.3 (2 C), 167.1 165.3, 138.2, 133.9, 133.4, 132.5, 132.1, 131.7, 131.6, 131.4, 131.2, 130.3, 130.0, 129.9, 129.4, 128.7, 128.6, 127.3, 124.1, 123.5, 123.9, 121.7, 118.8, 118.7, 118.6, 118.4, 64.6, 63.4, 51.7, 51.3, 32.62, 32.57, 30.7 (3 C), 30.5 (3 C), 26.7 (2 C), 23.5, 23.1, 19.0, 18.7. 13C NMR − carbon signals identified if possible. IR (solid): ṽ = 2949, 2861, 1624, 1540, 1460, 1390, 1362, 1367, 1272, 1247, 1217, 1094, 1016, 793, 729, 647, 620. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H56ClN6O2Zn: 873.3423. Found: 873.3412. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-3-ium]](2−)]zinc(II)}dichloride (8-Zn). Complex 8-Zn was prepared according to GP4. Ligand 8 (41.0 mg, 50 μmol, 1 equiv) was used, and the mixture was stirred for 3 h at room temperature. Compound 8-Zn (44.2 mg, 50 μmol, 100%) was isolated as a white solid. C48H54Cl2N6O2Zn, MW: 883.27 g·mol−1. Mp: 140 °C (decomp.). −1 1 [α]20 D = −644.0 (c = 0.1 g·mol , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 10.62 (s, 2 H, NCHNImid), 8.18 (s, 2 H, NCH), 7.74 (s, 2 H, NCHImid), 7.59−7.56 (m, 4 H, CHPh), 7.35−7.34 (m, 2 H, NCHImid, 2 H, CHAr), 7.24−7.06 (m, 6 H, CHPh, 2 H, CHAr), 5.63 (d, J = 13.1, 2 H, CArCH2), 4.83 (d, J = 13.1, 2 H, CArCH2), 3.37−3.32 (m, 2 H, N(CH)Ring), 2.37−2.33 (m, 2 H, (CH2)Ring), 1.95−1.91 (m, 2 H, (CH2)Ring), 1.44−1.32 (m, 4 H, (CH2)Ring), 1.23 (s, 18 H, C(CH3)3). 13 C NMR (125 MHz, CDCl3): δ = 167.5, 163.7, 137.1, 135.3, 135.2, 133.5, 131.9, 130.3 (2 C), 129.8, 125.5, 124.0, 122.7 (2 C), 120.1, 120.0, 65.4, 52.1, 34.0, 31.7 (3 C), 28.4, 24.8. IR (solid): ṽ = 2949, 1624, 1600, 1542, 1456, 1389, 1363, 1326, 1273, 1246, 1217, 1202, 1068, 1017, 832, 799, 759, 732, 687, 632. HRMS (ESI) m/e: Calcd for [M − Cl]+ C48H54ClN6O2Zn: 847.3266. Found: 847.3268. Synthesis of Ag−Carbene Complexes 6-M1, 7-M1, and 9-Zn. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}disilver(I)dichloride (7-Ni). Complex 7-Ni was prepared according to GP5a. Mononickel complex 5-Ni (45.1 mg, 50 μmol, 1 equiv) and Ag2O (23.4 mg, 100 μmol, 2 equiv) were used. Ag−carbene complex 7-Ni (50.8 mg, 46 μmol, 91%) was isolated as a red solid. L


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(125 MHz, CD2Cl2): δ = 162.9, 160.4, 157.0, 156.7, 140.8, 139.4, 138.9, 138.4, 138.0, 136.9, 136.7, 134.2, 133.6, 133.3, 133.1, 132.3, 131.7, 131.0, 130.9, 130.8, 126.2, 124.8, 124.5, 124.3, 123.5, 122.4, 121.8, 121.6, 121.3, 119.83, 119.79, 73.7, 72.2, 34.2, 34.1, 31.6 (3 C), 31.5 (3 C), 29.19, 19.16, 25.0, 24.8, 20.23, 20.15. IR (solid): ṽ = 2948, 1622, 1538, 1457, 1389, 1364, 1321, 1271, 1242, 1202, 1104, 1041, 833, 794, 735, 646, 552. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H55AgClN6O2Pd: 1021.2164. Found: 1021.2162. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2−)]zinc(II)}silver(I)dichloride (6-Zn). Complex 6-Zn was prepared according to GP5a. Monozinc complex 5-Zn (44.2 mg, 50 μmol, 1 equiv) and Ag2O (23.4 mg, 100 μmol, 2 equiv) were used. Ag−carbene complex 6-Zn (37.6 mg, 32 μmol, 67%) was isolated as a yellow solid. C50H55AgCl2N6O2Zn, MW: 1016.16 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −206.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 9.48 (t, J = 1.3, 1 H, NCHNImid), 8.21 (d, J = 2.0, 1 H, CNH), 8.09 (s, 1 H, CNH), 8.02−7.98 (m, 1 H, NCHImid), 7.48− 7.28 (m, 6 H, CHBiPh), 7.25 (d, J = 2.5, 1 H, CHAr), 7.23 (d, J = 2.5, 1 H, CHAr), 7.15 (d, J = 2.5, 1 H, CHAr), 7.12 (d, J = 2.5, 1 H, CHAr), 7.09 (t, J = 1.6, 1 H, NCHImid), 6.51 (t, J = 1.6, 1 H, NCHImid), 6.38 (t, J = 1.6, 1 H, NCHImid), 6.24 (t, J = 1.6, 1 H, NCHImid), 5.95 (d, J = 13.6, 1 H, CArCH2), 5.87 (d, J = 13.6, 1 H, CArCH2), 4.54 (d, J = 13.6, 1 H, CArCH2), 4.41 (d, J = 13.6, 1 H, CArCH2), 3.77−3.72 (m, 1 H, N(CH)Ring), 2.98−2.94 (m, 1 H, N(CH)Ring), 2.48−2.46 (m, 1 H, (CH2)Ring), 2.31−2.28 (m, 1 H, (CH2)Ring), 2.21 (s, 3 H, CBiPhCH3), 2.15 (s, 3 H, CBiPhCH3), 1.93−1.91 (m, 2 H, (CH2)Ring), 1.38−1.32 (m, 4 H, (CH2)Ring), 1.22 (s, 9 H, C(CH3)3), 1.19 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 178.7 (dd, J = 253.3, 20.1), 168.7, 167.4, 163.8, 161.9, 139.3, 139.11, 139.06, 137.8, 134.5, 133.9, 133.7, 133.6, 133.2, 132.7, 131.8, 131.6, 131.4, 130.8, 130.4, 130.3, 130.0, 128.6, 126.7, 125.7, 124.1, 124.0, 120.8, 120.51, 120.46, 120.31, 120.25, 119.9, 119.6, 66.1, 64.3, 54.6, 33.9, 33.8, 31.7 (3 C), 31.6 (3 C), 28.4, 27.7, 25.0, 24.6, 20.2. 20.1. IR (solid): ṽ = 2949, 2861, 1629, 1541, 1460, 1391, 1362, 1273, 1220, 1093, 1019, 832, 791, 734, 651, 629, 553. HRMS (ESI) m/e: Calcd for [M − HCl − Cl]+ C50H54AgClN6O2Zn: 943.2639. Found: 943.2617. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-1yl-2(3H)-yliden]](2−)]zinc(II)}silver(I)dichloroargentate(1−) (9-Zn). Complex 9-Zn was prepared according to GP5a. Monozinc complex 8-Zn (22.1 mg, 25 μmol, 1 equiv) and Ag2O (11.7 mg, 50 μmol, 2 equiv) were used. Ag−carbene complex 9-Zn (19.7 mg, 17 μmol, 72%) was isolated as a yellow solid. C48H52Ag2Cl2N6O2Zn, MW: 1096.99 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −428.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 8.22 (b, 2 H, NCHImid), 7.78 (b, 4 H, CHAr), 7.48−7.06 (m, 10 H, CHPh, 4 H, NCHimid), 5.64 (b, 2 H, CArCH2), 5.15 (b, 2 H, CArCH2), 3.55 (b, 1 H, N(CH)Ring), 3.03 (b, 1 H, N(CH)Ring), 2.31 (b, 2 H, (CH2)Ring), 1.95 (b, 2 H, (CH2)Ring), 1.40 (b, 2 H, (CH2)Ring), 1.37 (s, 18 H, C(CH3)3). 1H NMR - broad signals, allocated with HSQC. 13C NMR (125 MHz, CD2Cl2): δ = 183.0, 167.5, 139.7, 134.5, 132.2, 130.8, 129.3, 129.1, 128.8, 128.4, 127.3, 125.9, 123.5, 120.7, 120.1, 119.3, 117.9, 64.7, 54.4, 32.6, 30.6 (3 C), 27.2, 23.6. 13C NMR − carbon signals identified if possible. IR (solid): ṽ = 2947, 2862, 2359, 2323, 2285, 2185, 2164, 2051, 1981, 1629, 1597, 1543, 1497, 1454, 1410, 1390, 1362, 1325, 1273, 1244, 1219, 1200, 1088, 1017, 884, 859, 831, 800, 760, 731, 689, 631, 597, 557, 537. HRMS (ESI) m/e: Calcd for [M − (Cl − Ag − Cl)]+ C48H52AgN6O2Zn: 917.2482. Found: 917.2474. Synthesis of Cu−Carbene Complexes 10-M1 and 12-M1. {[1,1′[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol3-ium](2−)]nickel(II)}copper(I)dichloride (10-Ni). Complex 10-Ni was prepared according to GP5b, and mononickel complex 5-Ni (11.3 mg, 13 μmol, 1 equiv) and Cu2O (3.6 mg, 250 μmol, 2 equiv) were used. Cu−carbene complex 10-Ni (10.8 mg, 9 μmol, 93%) was isolated as a red/brown solid. C 50 H55 Cl 2CuN 6 NiO 2 , MW: 965.16 g·mol−1 . Mp: >200 °C −1 1 (decomp.). [α]20 D = −230.0 (c = 0.1 g·dL , CH2Cl2). H NMR

(300 MHz, CD2Cl2): δ = 9.01 (s, 1 H, NCHNImid), 7.63−7.27 (m, 2 H, NCH, 4 H, CHAr 6 H, CHBiPh), 7.14 (s, 1 H, NCHImid), 6.49 (s, 1 H, NCHImid), 6.16 (d, J = 1.5, 1 H, NCHImid), 6.10 (d, J = 1.5, 1 H, NCHImid), 5.81 (d, J = 12.7, 1 H, CArCH2), 5.80 (d, J = 14.1, 1 H, CArCH2), 4.79 (d, J = 13.6, 1 H, CArCH2), 4.59 (d, J = 13.6, 1 H, CArCH2), 3.40−3.36 (m, 1 H, N(CH)Ring), 2.95−2.90 (m, 1 H, N(CH)Ring), 2.56−2.50 (m, 2 H, (CH2)Ring), 2.35 (s, 3 H, CBiPhCH3), 2.26 (s, 3 H, CBiPhCH3), 1.99−1.96 (m, 2 H, (CH2)Ring), 1.47−1.39 (m, 2 H, (CH2)Ring), 1.36−1.34 (m, 2 H, (CH2)Ring), 1.30 (s, 9 H, C(CH3)3), 1.23 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 160.7, 158.4, 158.1, 157.5, 144.8, 139.9, 138.2, 137.4, 137.0, 136.0, 135.0, 132.5, 132.1, 131.8, 131.1, 130.6, 130.3, 130.13, 130.06, 130.0, 129.5, 124.8, 123.2, 122.9, 122.7, 121.7, 121.5, 120.9, 120.4, 119.4, 119.1, 118.1, 70.5, 68.5, 52.0, 50.7, 33.0, 32.9, 30.31 (3 C), 30.29 (3 C), 28.2, 28.1, 23.7, 23.5, 19.1, 19.0. IR (solid): ṽ = 2950, 2860, 1682, 1621, 1544, 1460, 1389, 1363, 1341, 1324, 1224, 1201, 1131, 1105, 1080, 1051, 908, 834, 793, 721, 646, 557. HRMS (ESI) m/e: Calcd for [M − Cl] + C50H55ClCuN6NiO2: 929.2720. Found: 929.2695. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2−)]palladium(II)}copper(I)dichloride (10-Pd). Complex 10-Pd was prepared according to GP5b, and mononickel complex 5-Pd (11.9 mg, 13 μmol, 1 equiv) and Cu2O (3.6 mg, 250 μmol, 2 equiv) were used. Cu−carbene complex 10-Pd (12.1 mg, 13 μmol, 99%) was isolated as a brown solid. C50H55Cl2CuN6O2Pd, MW: 1012.88 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −228.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 9.25 (s, 1 H, NCHNImid), 7.97 (s, 1 H, NCH), 7.88 (s, 1 H, NCH), 7.57−7.21 (m, 4 H, CHAr, 1 H, NCHImid, 6 H, CHBiPh), 6.57 (s, 1 H, NCHImid), 6.29 (s, 1 H, NCHImid), 6.25 (s, 1 H, NCHImid), 6.10 (d, J = 13.7, 1 H, CArCH2), 6.00 (d, J = 12.8, 1 H, CArCH2), 4.69 (d, J = 13.7, 1 H, CArCH2), 4.59 (d, J = 12.8, 1 H, CArCH2), 3.69−3.66 (m, 1 H, N(CH)Ring), 3.47−3.44 (m, 1 H, N(CH)Ring), 2.77−2.73 (m, 2 H, (CH2)Ring), 2.36 (s, 3 H, CBiPhCH3), 2.27 (s, 3 H, CBiPhCH3), 2.05−2.00 (m, 2 H, (CH2)Ring), 1.65−1.52 (m, 2 H, (CH2)Ring), 1.49−1.38 (m, 2 H, (CH2)Ring), 1.32 (s, 9 H, C(CH3)3), 1.26 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 163.0, 160.5, 157.0, 156.7, 140.8, 139.3, 138.6, 138.4, 137.9, 136.9, 136.6, 134.1, 133.7, 133.5, 133.3, 133.1, 132.1, 131.6, 131.3, 130.9, 130.6, 126.3, 124.9, 124.6, 124.0, 123.7, 122.4, 121.8, 121.2, 121.0, 119.4, 73.9, 72.3, 53.2, 52.7, 34.2, 34.0, 31.6 (3 C), 31.5 (3 C), 29.2, 25.0, 24.9. IR (solid): ṽ = 2952, 2924, 1680, 1622, 1538, 1454, 1440, 1386, 1363, 1320, 1271, 1244, 1219, 1201, 1130, 1097, 1040, 907, 833, 792, 720, 646, 551. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H55ClCuN6O2Pd: 977.2404. Found: 977.2400. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2−)]zinc(II)}copper(I)dichloride (10-Zn). Complex 10-Zn was prepared according to GP5b, and mononickel complex 5-Zn (11.4 mg, 13 μmol, 1 equiv) and Cu2O (3.6 mg, 25 μmol, 2 equiv) were used. Cu−carbene complex 10-Zn (9.8 mg, 8 μmol, 81%) was isolated as a green/brown solid. C 50 H55Cl2 CuN 6 O2Pd, MW: 971.84 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −286.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CDCl3): δ = 9.64 (s, 1 H, NCHNImid), 8.28 (s, 1 H, NCH), 8.10 (s, 1 H, NCH), 8.02 (d, 1 H, CHBiPh), 7.52−7.36 (m, 5 H, CHBiPh), 7.22 (d, J = 2.3, 1 H, CHAr), 7.16 (d, J = 2.3, 1 H, CHAr), 7.11 (d, J = 2.3, 1 H, CHAr), 7.10 (d, J = 2.3, 1 H, CHAr), 7.04 (s, 1 H, NCHImid), 6.50 (d, J = 1.7, 1 H, NCHImid), 6.37 (s, 1 H, NCHImid), 6.20 (d, J = 1.71 H, NCHImid), 6.15 (d, J = 13.7, 1 H, CArCH2), 6.10 (d, J = 12.6, 1 H, CArCH2), 4.52 (d, J = 13.7, 1 H, CArCH2), 4.46 (d, J = 12.6, 1 H, CArCH2), 3.94−3.90 (m, 1 H, N(CH)Ring), 2.56−2.54 (m, 1 H, N(CH)Ring), 2.37−2.35 (m, 2 H, (CH2)Ring), 2.26 (s, 3 H, CBiPhCH3), 2.22 (s, 3 H, CBiPhCH3), 2.02−1.99 (m, 2 H, (CH2)Ring), 1.51−1.54 (m, 2 H, (CH2)Ring), 1.41−1.35 (m, 2 H, (CH2)Ring), 1.26 (s, 9 H, C(CH3)3), 1.22 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 175.2, 168.6, 163.8, 161.3, 140.8, 138.7, 138.5, 138.4, 138.1, 138.0, 137.8, 133.8, 133.3, 133.2, 133.0, 132.8, 132.6, 132.2, 131.0, 130.8, 130.5, 130.2, 128.4, 126.6, M


Organometallics

Article

1.90−1.87 (m, 2 H, (CH2)Ring), 1.37−1.27 (m, 4 H, (CH2)Ring), 1.21 (s, 9 H, C(CH3)3), 1.17 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 172.4, 170.0, 161.8, 161.5, 157.1, 156.8, 138.4, 137.54, 137.46, 137.2, 136.1, 135.3, 134.5, 131.3, 131.0, 130.7, 130.31, 130.25, 129.2, 128.8, 128.6, 127.7, 127.2, 127.1, 123.6, 121.1, 120.9, 120.7, 120.1, 119.2, 118.3, 71.1, 67.9, 50.7, 48.9, 33.6, 33.5, 31.44 (3 C), 31.39 (3 C), 29.7, 29.4, 28.6, 28.4, 20.1, 19.8. IR (solid): ṽ = 2923, 2851, 1622, 1551, 1461, 1413, 1395, 1362, 1343, 1319, 1275, 1259, 1222, 1191, 1129, 1102, 1049, 916, 867, 837, 785, 754, 733, 713, 675, 643, 560. HRMS (ESI) m/e: Calcd for [M − Au − Cl + H]+ C50H55AuClN6NiO2: 1061.3089. Found: 1061.3057. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2−)]nickel(II)}gold(I)dichloride (14-Ni). Complex 14-Ni was prepared according to GP6a. Ag−carbene complex 7-Ni (14.0 mg, 13.00 μmol, 1 equiv) and AuCl(SMe2) (3.7 mg, 13.00 μmol, 1 equiv) were used. Bimetallic complex 14-Ni (0.4 mg, 0.37 μmol, 3%) was isolated as a red solid. C50H55AuCl2NiN6O2, MW: 1098.58 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −199.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 8.08 (t, J = 1.3, 1 H, NCHNImid), 7.67 (t, J = 4.7, 1 H, CHBiPh), 7.53−7.32 (m, 2 H, NCH, 5 H, CHBiPh), 7.22 (d, J = 2.5, 1 H, CHAr), 7.15 (d, J = 2.5, 1 H, CHAr), 7.13 (d, J = 2.5, 1 H, CHAr), 7.04 (d, J = 2.5, 1 H, CHAr), 6.93 (t, J = 1.9, 1 H, NCHImid), 6.36 (d, J = 1.9, 1 H, NCHImid), 6.29 (d, J = 1.9, 1 H, NCHImid), 6.20 (d, J = 1.9, 1 H, NCHImid), 6.09 (d, J = 12.8, 1 H, CArCH2), 6.06 (d, J = 13.9, 1 H, CArCH2), 4.41 (d, J = 12.8, 1 H, CArCH2), 4.37 (d, J = 13.9, 1 H, CArCH2), 3.35−3.32 (m, 1 H, N(CH)Ring), 3.10−3.05 (m, 1 H, N(CH)Ring), 2.52−2.50 (m, 1 H, (CH2)Ring), 2.43−2.40 (m, 1 H, (CH2)Ring), 2.18 (s, 3 H, CBiPhCH3), 2.11 (s, 3 H, CBiPhCH3), 1.92−1.87 (m, 2 H, (CH2)Ring), 1.39−1.25 (m, 4 H, (CH2)Ring), 1.23 (s, 9 H, C(CH3)3), 1.19 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 170.1, 161.0, 160.2, 157.22, 157.19, 138.7, 138.4, 137.4, 137.2, 136.8, 136.3, 134.5, 132.3, 131.2, 130.9, 130.8, 130.7, 130.6, 129.8, 129.4, 129.17, 129.15, 127.3, 127.1, 126.6, 123.42, 123.36, 121.22, 121.16, 120.5, 119.5, 70.6, 68.9, 51.4, 50.0, 33.7, 33.6, 31.5 (3 C), 31.4, (3 C), 28.7, 28.5, 24.5, 24.3. IR (solid): ṽ = 2922, 2852, 1720, 1620, 1554, 1461, 1414, 1388, 1363, 1339, 1317, 1274, 1222, 1123, 1101, 1074, 1049, 1019, 919, 867, 836, 730, 646, 560. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H55AuClN6NiO2: 1061.3089. Found: 1061.3057. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2−)]palladium(II)}gold(I)dichloride (14-Pd). Complex 14-Pd was prepared according to GP6a. Ag−carbene complex 6-Pd (14.5 mg, 13 μmol, 1 equiv) and AuCl(SMe2) (7.4 mg, 25 μmol, 2 equiv) were used. Bimetallic complex 14-Pd (8.3 mg, 7 μmol, 60%) was isolated as a yellow solid. C50H55AuCl2N6O2Pd, MW: 1146.30 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −235.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CD2Cl2): δ = 9.27 (s, 1 H, NCHNImid), 7.94 (d, J = 1.8, 1 H, NCH), 7.91 (d, J = 1.8, 1 H, NCH), 7.68 (t, J = 8.0, 1 H, CHBiPh), 7.55−7.36 (m, 4 H, CHAr, 4 H, CHBiPh), 7.24 (d, J = 8.0, 1 H, CHBiPh), 7.15 (t, J = 1.9, 1 H, NCHImid), 6.60 (d, J = 1.9, 1 H, NCHImid), 6.31 (d, J = 1.9, 1 H, NCHImid), 6.26 (d, J = 1.9, 1 H, NCHImid), 6.18 (d, J = 12.3, 1 H, CArCH2), 6.15 (d, J = 14.6, 1 H, CArCH2), 4.64 (d, J = 14.6, 1 H, CArCH2), 4.44 (d, J = 12.3, 1 H, CArCH2), 3.95−3.90 (m, 1 H, N(CH)Ring), 3.40−3.36 (m, 1 H, N(CH)Ring), 2.86−2.84 (m, 1 H, (CH2)Ring), 2.73−2.70 (m, 1 H, (CH2)Ring), 2.34 (s, 3 H, CBiPhCH3), 2.23 (s, 3 H, CBiPhCH3), 2.07−1.97 (m, 4 H, (CH2)Ring), 1.80−1.77 (m, 1 H, (CH2)Ring), 1.65−1.56 (m, 1 H, (CH2)Ring), 1.43−1.40 (m, 1 H, (CH2)Ring), 1.31 (s, 9 H, C(CH3)3), 1.26 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 169.2, 162.5, 160.0, 156.44, 156.41, 139.7, 138.7, 138.0, 137.6, 137.4, 136.6, 136.0, 133.5, 133.4, 133.1, 133.0, 132.0, 131.7, 131.3, 130.3, 129.7, 126.5, 124.7, 124.4, 123.4, 122.5, 122.2, 121.2, 120.9, 120.5, 119.0, 73.1, 72.1, 53.5, 52.6, 33.8, 33.7, 31.42 (3 C), 31.39 (3 C), 29.74, 28.65, 24.7, 24.3, 20.1, 19.9. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H55AuClN6O2Pd: 1111.2777. Found: 1111.2766.

125.1, 124.7, 124.0, 123.2, 120.0, 119.6, 119.4, 119.2, 65.6, 63.6, 54.6, 53.1, 33.6, 33.5, 31.61 (3 C), 31.56 (3 C), 28.1, 27.3, 24.8, 24.1, 20.0, 19.8. IR (solid): ṽ = 2950, 2928, 2859, 1624, 1540, 1460, 1390, 1362, 1273, 1243, 1220, 1201, 1129, 1081, 1019, 976, 882, 861, 832, 798, 734, 715, 648, 601, 584. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H55ClCuN6O2Zn: 934.2562. Found: 934.2585. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-1yl-2(3H)-yliden]](2−)]nickel(II)}copper(II)dichloride (12-Ni). Complex 12-Ni was prepared according to GP5b, and mononickel complex 11-Ni (21.9 mg, 25 μmol, 1 equiv) and Cu2O (7.2 mg, 50 μmol, 2 equiv) were used. Cu−carbene complex 12-Ni (21.0 mg, 22 μmol, 89%) was isolated as a red/brown solid. C48H52Cl2CuN6NiO2, MW: 938.11 g·mol−1. Mp: 195−197 °C −1 1 (decomp.). [α]20 D = −263.0 (c = 0.1 g·dL , CH2Cl2). H NMR: paramagnetic species. 13C NMR: paramagnetic species. IR (solid): ṽ = 2949, 2858, 1681, 1621, 1597, 1545, 1499, 1440, 1390, 1363, 1341, 1307, 1244, 1221, 1098, 1071, 1044, 955, 907, 864, 833, 797, 759, 733, 691, 643, 630, 536. HRMS (ESI) m/e: Calcd for [M + 2H]+ C48H54Cl2CuN6NiO2: 903.2543. Found: 903.2583. Anal. Calcd for [C48H52Cl2CuN6NiO2+CDCl3]: C: 55.60, H: 5.14. Found: C: 55.90, H: 5.46. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-1yl-2(3H)-yliden]](2−)]palladium(II)}copper(II)dichloride (12-Pd). Complex 12-Pd was prepared according to GP5b, and mononickel complex 11-Pd (23.1 mg, 25 μmol, 1 equiv) and Cu2O (7.2 mg, 50 μmol, 2 equiv) were used. Cu−carbene complex 12-Pd (18.2 mg, 18 μmol, 73%) was isolated as a yellow/green solid. C48H52Cl2CuN6O2Pd, MW: 985.84 g·mol−1. Mp: 188−190 °C −1 1 (decomp.). [α]20 D = −371.0 (c = 0.1 g·dL , CH2Cl2). H NMR: 13 paramagnetic species. C NMR: paramagnetic species. IR (solid): ṽ = 2949, 2861, 1684, 1621, 1597, 1540, 1500, 1441, 1388, 1364, 1320, 1271, 1247, 1219, 1097, 1071, 1042, 956, 833, 795, 760, 734, 691, 632, 614, 590, 553. HRMS (ESI) m/e: Calcd for [M + 2H]+ C48H54Cl2CuN6O2Pd: 987.2009. Found: 987.1997. Anal. Calcd for [C48H52Cl2CuN6O2Pd+2CH2Cl2]: C: 51.96, H: 4.88. Found: C: 51.90, H: 5.28. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-1yl-2(3H)-yliden]](2−)]zinc(II)}copper(II)dichloride (12-Zn). Complex 12-Zn was prepared according to GP5b, and mononickel complex 11-Zn (22.1 mg, 25 μmol, 1 equiv) and Cu2O (7.2 mg, 50 μmol, 2 equiv) were used. Cu−carbene complex 12-Zn (18.4 mg, 19 μmol, 78%) was isolated as a pale green solid. C 48 H52 Cl2 CuN6 O2Zn, MW: 944.80 g·mol−1 . Mp: >200 °C −1 1 (decomp.). [α]20 D = −431.0 (c = 0.1 g·dL , CH2Cl2). H NMR: 13 paramagnetic species. C NMR: paramagnetic species. IR (solid): ṽ = 3088, 3053, 2950, 2860, 1629, 1542, 1453, 1391, 1363, 1324, 1275, 1245, 1220, 1201, 1098, 1017, 884, 859, 832, 799, 759, 731, 688, 631, 522. HRMS (ESI) m/e: Calcd for [M − Cl]+ C48H52ClCuN6O2Zn: 908.2405. Found: 908.2409. Anal. Calcd for [C48H52Cl2CuN6O2Zn + H2O]: C: 59.85, H: 5.65. Found: C: 59.99, H: 6.00. Synthesis of Macrocyclic Bimetallic Salen−NHC−Au Complexes 13-M1 and 14-M1. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1Himidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}digold(I)dichloride (13-Ni). Complex 13-Ni was prepared according to GP6a. Ag−carbene complex 7-Ni (14.0 mg, 13 μmol, 1 equiv) and AuCl(SMe2) (7.4 mg, 20 μmol, 2 equiv) were used. Bimetallic complex 13-Ni (6.5 mg, 5 μmol, 40%) was isolated as a red solid. C50H54Au2Cl2N6NiO2, MW: 1294.53 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −228.0 (c = 0.1 g·dL , CH2Cl2). H NMR (300 MHz, CDCl3): δ = 7.69−7.64 (m, 2 H, CHBiPh), 7.42−7.30 (m, 2 H, NCH, 4 H, CHBiPh), 7.19 (d, J = 2.5, 1 H, CHAr), 7.07 (d, J = 2.5, 1 H, CHAr), 7.02 (d, J = 2.5, 1 H, CHAr), 7.00 (d, J = 2.5, 1 H, CHAr), 6.97 (d, J = 1.9, 1 H, NCHImid), 6.36 (d, J = 1.9, 1 H, NCHImid), 6.27 (d, J = 1.9, 1 H, NCHImid), 6.25 (d, J = 1.9, 1 H, NCHImid), 5.21 (d, J = 13.1, 1 H, CArCH2), 6.18 (d, J = 14.0, 1 H, CArCH2), 4.41 (d, J = 13.1, 1 H, CArCH2), 4.36 (d, J = 14.0, 1 H, CArCH2), 3.18−3.14 (m, 1 H, N(CH)Ring), 3.03−2.97 (m, 1 H, N(CH)Ring), 2.51−2.49 (m, 1 H, (CH2)Ring), 2.40−2.37 (m, 1 H, (CH2)Ring), 2.09 (s, 3 H, CBiPhCH3), N


Organometallics

Article

{[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(2′-(1H-imidazol-1yl-2(3H)-yliden)-(6,6′-dimethyl-[1,1′-biphenyl]-2-yl)-1H-imidazol-3-ium](2−)]zinc(II)}gold(I)dichloride (14-Zn). Complex 14-Zn was prepared according to GP6a. Ag−carbene complex 6-Zn (21.1 mg, 19 mmol, 1 equiv) and AuCl(SMe2) (5.5 mg, 19 μmol l, 1 equiv) were used. Bimetallic complex 14-Zn (13.1 mg, 12 μmol, 64%) was isolated as a pale yellow solid. C50H55AuCl2N6O2Zn, MW: 1105.26 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −149.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 9.77 (s, 1 H, NCHNImid), 8.30 (d, J = 1.8, 1 H, NCH), 8.12 (d, J = 1.8, 1 H, NCH), 8.03 (d, J = 8.0, 1 H, CHBiPh), 7.60−7.49 (m, 3 H, CHBiPh), 7.41 (t, J = 8.0, 1 H, CHBiPh), 7.36 (d, J = 8.0, 1 H, CHBiPh), 7.23 (d, J = 2.5, 1 H, CHAr), 7.19 (d, J = 2.5, 1 H, CHAr), 7.13 (d, J = 2.5, 1 H, CHAr), 7.12 (d, J = 2.5, 1 H, CHAr), 7.08 (d, J = 1.9, 1 H, NCHImid), 6.54 (t, J = 1.9, 1 H, NCHImid), 6.40 (d, J = 1.9, 1 H, NCHImid), 6.25 (d, J = 12.5, 1 H, CArCH2), 6.24 (d, J = 1.9, 1 H, NCHImid), 6.22 (d, J = 15.2, 1 H, CArCH2), 4.52 (d, J = 13.7, 1 H, CArCH2), 4.37 (d, J = 13.7, 1 H, CArCH2), 3.96−3.92 (m, 1 H, N(CH)Ring), 3.03−3.00 (m, 1 H, N(CH)Ring), 2.58−2.55 (m, 1 H, (CH2)Ring), 2.38−2.36 (m, 1 H, (CH2)Ring), 2.27 (s, 3 H, CBiPhCH3), 2.20 (s, 3 H, CBiPhCH3), 2.02−1.98 (m, 2 H, (CH2)Ring), 1.53−1.36 (m, 4 H, (CH2)Ring), 1.26 (s, 9 H, C(CH3)3), 1.24 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 169.4, 168.5, 167.2, 163.7, 161.3, 138.3, 138.1, 137.9, 133.8, 133.4, 133.2, 133.1, 132.9, 132.5, 132.2, 131.1, 131.0, 130.9, 130.7, 130.0, 129.6, 128.4, 127.5, 125.2, 123.42, 123.37, 119.8, 119.69, 119.65, 119.4, 119.2, 65.6, 63.6, 54.4, 53.2, 33.6, 33.5, 31.61 (3 C), 31.57 (3 C), 28.0, 27.2, 24.7, 24.1, 20.0, 19.8. HRMS (ESI) m/e: Calcd for [M − Cl]+ C50H54AuClN6O2Zn: 1069.3010. Found: 1069.3024. Synthesis of Open Bimetallic Salen−bis-NHC−Au Complexes 15-M 1 . {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-1yl-2(3H)-yliden]](2−)]nickel(II)}digold(I)dichloride (15-Ni). Complex 15-Ni was prepared according to GP6b. Ag−carbene complex 9-Ni (13.6 mg, 13 μmol, 1 equiv) and AuCl(SMe2) (7.4 mg, 25 μmol, 2 equiv) were used. Bimetallic complex 15-Ni (15.1 mg, 12 μmol, 95%) was isolated as a red solid. C48H52Au2Cl2N6NiO2, MW: 1268.50 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −474.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 8.08 (d, J = 1.9, 2 H, NCHImid), 7.82 (d, J = 2.5, 2 H, CHAr), 7.63−7.61 (m, 4 H, CHPh), 7.52 (s, 2 H, NCH), 7.47−7.40 (m, 6 H, CHPh), 7.21 (d, J = 1.9, 2 H, NCHimid), 7.16 (d, J = 2.5, 2 H, CHAr), 5.49 (d, J = 13.9, 2 H, CArCH2), 5.41 (d, J = 13.9, 2 H, CArCH2), 3.07−3.06 (m, 2 H, N(CH)Ring), 2.54−2.52 (m, 2 H, (CH2)Ring), 1.99− 1.98 (m, 2 H, (CH2)Ring), 1.41−1.35 (m, 4 H, (CH2)Ring), 1.29 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 169.6, 160.6, 158.0, 139.2, 138.5, 134.3, 129.6 (2 C), 129.5, 128.9, 126.0, 124.7 (2 C), 123.6, 121.3, 119.6, 70.2, 51.9, 33.9, 31.4 (3 C), 29.7, 28.9, 24.4. IR (solid): ṽ = 3123, 2958, 2923, 1619, 1596, 1552, 1497, 1441, 1415, 1389, 1363, 1339, 1307, 1274, 1241, 1221, 1156, 1132, 1101, 1074, 1056, 1023, 960, 868, 836, 799, 762, 732, 692, 633, 598, 563, 544. HRMS (ESI) m/e: Calcd for [M − (Cl − Au − Cl)]+ C48H52AuN6NiO2: 999.3165. Found: 999.3160. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]bis[1-phenyl-1H-imidazol-1yl-2(3H)-yliden]](2−)]palladium(II)}digold(I)dichloride (15-Pd). Complex 15-Pd was prepared according to GP6a. Ag−carbene complex 9-Pd (14.0 mg, 13 μmol, 1 equiv) and AuCl(SMe2) (7.4 mg, 25 μmol, 2 equiv) were used. Bimetallic complex 15-Pd (15.6 mg, 12 μmol, 95%) was isolated as a yellow solid. C48H52Au2Cl2N6O2Pd, MW: 1316.24 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −297.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 8.06 (s, 2 H, NCHImid), 7.93 (d, J = 1.5, 2 H, CHAr), 7.83 (s, 2 H, NCH), 7.62−7.59 (m, 4 H, CHPh), 7.46−7.38 (m, 6 H, CHPh), 7.25 (s, 2 H, NCHimid), 7.17 (d, J = 1.5, 2 H, CHAr), 5.60 (d, J = 13.3, 2 H, CArCH2), 5.56 (d, J = 13.3, 2 H, CArCH2), 3.49−3.47 (m, 2 H, N(CH)Ring), 2.73−2.70 (m, 2 H, (CH2)Ring), 2.05−2.04 (m, 2 H, (CH2)Ring), 1.63−1.58 (m, 2 H, (CH2)Ring), 1.46−1.42 (m, 2 H, (CH2)Ring), 1.31 (s, 18 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 169.8, 161.8, 156.0, 139.2, 138.3, 135.2, 131.4, 139.6 (2 C), 128.8, 126.5, 124.7 (2 C), 123.5, 120.9, 120.2, 72.6, 52.3, 33.9, 31.4 (3 C), 29.7, 28.7, 24.5. IR (solid): ṽ = 3129, 2957, 2923, 2852, 1681, 1596, 1536, 1497,

1441, 1416, 1382, 1363, 1338, 1320, 1270, 1239, 1201, 1155, 1125, 1098, 1073, 1046, 960, 909, 866, 833, 797, 762, 731, 692, 642, 558, 544. HRMS (ESI) m/e: Calcd for [M − (Cl − Au − Cl)]+ C48H52AuN6O2Pd: 1047.2863. Found: 1047.2844. Synthesis of Macrocyclic Bimetallic Salen−NHC−Pd Complexes 16-M1. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl2(3H)-yliden)](2-)]nickel(II)}palladium(II)dichloride (16-Ni). Complex 16-Pd was prepared according to GP6a. Ag−carbene complex 7-Pd (89.1 mg, 75 μmol, 1.0 equiv) and Pd2(dba)3 (44.1 mg, 45 μmol, 0.6 equiv) were used. Bimetallic complex 16-Pd (80.8 mg, 39 μmol, 52%) was isolated as a red solid. C50H54Cl2N6NiO2Pd, MW: 1007.02 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = −28.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 7.93 (d, J = 7.8, 1 H, CHBiPh), 7.57 (t, J = 7.8, 1 H, CHBiPh), 7.43 (s, 2 H, NCH), 7.42 (d, J = 7.8, 1 H, CHBiPh), 7.36 (d, J = 2.2, 1 H, CHAr), 7.33 (d, J = 2.2, 1 H, CHAr), 7.13 (d, J = 7.8, 2 H, CHBiPh), 7.07 (d, J = 2.2, 1 H, CHAr), 7.03 (d, J = 2.2, 1 H, CHAr), 6.90 (d, J = 7.8, 1 H, CHBiPh), 6.75 (t, J = 7.8, 1 H, CHBiPh), 6.58 (d, J = 1.6, 1 H, NCHImid), 6.51 (d, J = 1.6, 1 H, NCHImid), 6.41 (d, J = 1.6, 1 H, NCHImid), 6.34 (d, J = 1.6, 1 H, NCHImid), 6.28 (d, J = 14.2, 1 H, CArCH2), 6.16 (d, J = 15.5, 1 H, CArCH2), 5.41 (d, J = 12.9, 1 H, CArCH2), 4.40 (d, J = 12.9, 1 H, CArCH2), 3.15−3.13 (m, 1 H, N(CH)Ring), 3.03−2.99 (m, 1 H, N(CH)Ring), 2.49−2.47 (m, 1 H, (CH2)Ring), 2.39−2.36 (m, 1 H, (CH2)Ring), 2.15 (s, 3 H, CBiPhCH3), 1.94 (s, 3 H, CBiPhCH3), 1.26−1.30 (m, 4 H, (CH2)Ring), 1.27 (s, 9 H, C(CH3)3), 1.23 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 162.2, 161.9, 160.6, 158.2, 157.3, 139.0, 138.9, 137.0, 136.9, 136.3, 135.7, 135.2, 135.0, 132.2, 131.5, 129.7, 129.5, 129.1, 128.9, 128.7128.1, 127.7, 127.2, 125.8, 124.6, 121.9, 120.4, 120.1, 119.2, 118.9, 70.7, 68.7, 57.4, 48.4, 33.7, 33.6, 31.4 (3 C), 31.3 (3 C), 29.1, 28.8, 24.39, 24.35, 20.1, 19.8. IR (solid): ṽ = 2948, 2861, 1619, 1544, 1455, 1391, 1363, 1338, 1272, 1222, 1169, 1131, 1105, 1049, 950, 868, 834, 791, 740, 717, 691, 655, 631, 613, 555. HRMS (ESI) m/e: Calcd for [M − 2Cl]2+ C50H54N6NiO2Pd: 468.1342. Found: 468.1348. Anion Exchanged Salen−Ni−Bis-NHC−Pd Complexes 18-M1. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}palladium(II)diacetate (18-Ni-OAc). For the anion exchange of complex 16-Ni (15.0 mg, 15 μmol, 1 equiv) according to GP7, AgOAc (5.0 mg, 30 μmol, 2 equiv) was used. Complex 18-Ni-OAc (12.6 mg, 12 μmol, 80%) was isolated as an orange solid. C54H60N6NiO6Pd, MW: 1054.20 g·mol−1. Mp: 178−180 °C −1 1 (decomp.). [α]20 D = −55.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 7.71 (d, J = 7.8, 1 H, CHBiPh), 7.57 (t, J = 7.8, 1 H, CHBiPh), 7.47−7.31 (m, 2 H, NCH, 2 H, CHAr, 1 H, CHBiPh), 7.14 (d, J = 8.5, 1 H, CHBiPh), 7.06 (d, J = 2.5, 1 H, CHAr), 7.01 (d, J = 2.5, 1 H, CHAr), 6.88 (d, J = 7.8, 2 H, CHBiPh), 6.70 (t, J = 7.8, 1 H, CHBiPh), 6.60 (d, J = 1.9, 1 H, NCHImid), 6.47 (d, J = 1.9, 1 H, NCHImid), 6.40 (d, J = 1.9, 1 H, NCHImid), 6.33 (d, J = 1.9, 1 H, NCHImid), 6.32 (d, J = 13.3, 1 H, CArCH2), 6.03 (d, J = 13.3, 1 H, CArCH2), 4.96 (d, J = 13.3, 1 H, CArCH2), 4.63 (d, J = 13.3, 1 H, CArCH2), 3.12 (b, 2 H, N(CH)Ring), 2.47−2.44 (m, 1 H, (CH2)Ring), 2.33−2.35 (m, 1 H, (CH2)Ring), 2.16 (s, 3 H, CBiPhCH3), 1.98−1.95 (b, 6 H, OC(O)CH3), 1.88 (s, 3 H, CBiPhCH3), 1.68−1.58 (m, 2 H, (CH2)Ring), 1.35−1.31 (m, 4 H, (CH2)Ring), 1.27 (s, 9 H, C(CH3)3), 1.24 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CDCl3): δ = 162.5, 139.6, 138.6, 137.2, 137.1, 136.3, 135.69, 135.67, 135.3, 132.1, 131.3, 129.7, 128.6, 127.7, 126.6, 125.6, 121.6, 120.2, 119.0, 55.4, 48.9, 33.7, 33.6, 31.4 (3 C), 31.3 (3 C), 29.71, 29.67, 24.6, 24.3, 19.9, 19.8. 13C NMR − carbon signals identified if possible. IR (solid): ṽ = 3365, 2922, 2853, 1619, 1546, 1458, 1388, 1364, 1327, 1272, 1223, 1104, 1048, 1016, 926, 869, 835, 795, 737, 695, 614, 559. HRMS (ESI) m/e: Calcd for [M − 2CH2 + Na]+ C52H54N6NiO6Pd: 1047.2386. Found: 1047.2406. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}palladium(II)diheptafluorobutyrate (18-Ni-O2CC3F7). For the anion exchange of complex 16-Ni (15.0 mg, 15 μmol, 1 equiv) according to GP7, AgO2CC3F7 (9.6 mg, 30 μmol, 2 equiv) was used. O


Organometallics

Article

Complex 18-Ni-O2CC3F7 (18.4 mg, 13 μmol, 90%) was isolated as an orange solid. C58H54F14N6NiO6Pd, MW: 1362.18 g·mol−1. Mp: 190−192 °C −1 1 (decomp.). [α]20 D = −169.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CDCl3): δ = 7.61−7.36 (m, 3 H, CHBiPh, 2 H, NCH, 2 H, CHAr), 7.21 (b, 1 H, CHAr), 7.06−7.01 (m, 1 H, CHBiPh, 1 H, CHAr), 6.89 (d, J = 7.8, 2 H, CHBiPh), 6.60−6.64 (m, 1 H, NCHImid, 1 H. CHBiPh), 6.53 (b, 1 H, NCHImid), 6.47 (b, 1 H, NCHImid), 6.36 (b, 1 H, NCHImid), 6.30 (d, J = 15.6, 1 H, CArCH2), 6.04 (d, J = 13.0, 1 H, CArCH2), 4.64 (d, J = 15.6, 1 H, CArCH2), 4.53 (d, J = 13.0, 1 H, CArCH2), 3.12−3.07 (m, 1 H, N(CH)Ring), 2.98−2.93 (m, 1 H, N(CH)Ring), 2.47−2.40 (m, 2 H, (CH2)Ring), 2.16 (s, 3 H, CBiPhCH3), 1.94 (s, 3 H, CBiPhCH3), 1.72−1.62 (m, 2 H, (CH2)Ring), 1.44−1.28 (m, 4 H, (CH2)Ring), 1.27 (s, 9 H, C(CH3)3), 1.24 (s, 9 H, C(CH3)3). 1H NMR -broad signals, allocated with HSQC. 13C NMR (125 MHz, CDCl3): δ = 165.5, 129.8, 33.7, 33.6, 31.3 (3 C), 31.2 (3 C), 30.1, 30.0, 24.27, 24.31, 19.75, 19.73. 13C NMR − carbon signals identified if possible; a spectrum with satisfactory signal intensity could not be obtained until now. IR (solid): ṽ = 2953, 2922, 2360, 2340, 1685, 1621, 1551, 1459, 1389, 1365, 1328, 1273, 1222, 1203, 1158, 1113, 1075, 1050, 961, 925, 834, 792, 740, 718, 695, 653, 633, 597, 555, 530. HRMS (ESI) m/e: Calcd for [M − C4F7O2]+ C54H54F7N6NiO4Pd: 1149.2479. Found: 1149.2497. Anion Exchanged Salen−Ni−Bis-NHC−Pd Complexes 17-Ni. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}palladium(II)ditriflate (17-Ni-OTf). For the anion exchange of complex 16-Ni (10.0 mg, 10 μmol, 1 equiv) according to GP7, AgOTf (5.1 mg, 20 μmol, 2 equiv) was used. Activated complex 17-Ni-OTf (12.3 mg, 10 μmol, 100%) was isolated as a yellow solid. C52H54F6N6NiO8PdS2, MW: 1234.25 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = +59.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 8.25 (d, J = 7.8, 1 H, CHBiPh), 7.82 (t, J = 7.8, 2 H, CHBiPh), 7.71 (b, 1 H, NCH), 7.55−7.51 (m, 1 H, NCH, 2 H, CHBiPh, 1 H, NCHImid), 7.49 (d, J = 2.5, 1 H, CHAr), 7.45 (d, J = 2.5, 1 H, CHAr), 7.30−7.27 (m, 2 H, CHAr), 6.95 (d, J = 1.9, 1 H, NCHImid), 6.87− 6.86 (m, 1 H, NCHImid, 1 H, CHBiPh), 6.83 (d, J = 1.9, 1 H, NCHImid), 6.54 (d, J = 14.4, 1 H, CArCH2), 5.80 (d, J = 14.4, 1 H, CArCH2), 4.98 (d, J = 14.4, 1 H, CArCH2), 4.89 (d, J = 14.4, 1 H, CArCH2), 3.76−3.74 (m, 1 H, N(CH)Ring), 3.11−3.08 (m, 1 H, N(CH)Ring), 2.61−2.54 (m, 2 H, (CH2)Ring), 2.34 (s, 3 H, CBiPhCH3), 2.05 (s, 3 H, CBiPhCH3), 1.98−1.95 (m, 4 H, (CH2)Ring), 1.50−1.47 (m, 4 H, (CH2)Ring), 1.42−1.32 (m, 4 H, (CH2)Ring), 1.29 (s, 9 H, C(CH3)3), 1.28 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 163.1, 161.4, 153.6, 152.7, 144.0, 143.8, 138.2, 137.90, 137.88, 137.8, 136.4, 135.4, 134.7, 134.5, 133.2, 132.3, 131.8, 131.0, 130.0, 127.9, 127.5, 136.6, 125.7, 124.7, 122.7, 70.9, 72.6, 52.4, 49.7, 34.4, 34.3, 31.2 (3 C), 31.1 (3 C), 29.5, 29.4, 24.6, 24.3, 20.0, 19.7. IR (solid): ṽ = 3500, 3101, 2953, 2866, 1724, 1632, 1573, 1463, 1417, 1396, 1364, 1251, 1223, 1152, 1053, 1028, 870, 834, 794, 744, 696, 636, 572, 516. HRMS (ESI) m/e: Calcd for [M − OTf]+ C51H54F3N6NiO5PdS: 1085.2210. Found: 1085.2225. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}palladium(II)diperchlorate (17-Ni-ClO4). For the anion exchange of complex 16-Ni (10.0 mg, 10 μmol, 1 equiv) according to GP7, AgClO4 (4.5 mg, 20 μmol, 2 equiv) was used. Activated complex 17-Ni-ClO4 (11.3 mg, 9 μmol, 91%) was isolated as a yellow solid. C50H54Cl2N6NiO10Pd, MW: 1135.02 g·mol−1. Mp: >200 °C −1 1 (decomp.). [α]20 D = +77.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 8.34 (d, J = 7.6, 1 H, CHBiPh), 7.89 (t, J = 7.6, 1 H, CHBiPh), 7.65 (b, 1 H, NCH), 7.53−7.55 (m, 1 H, NCH, 3 H, CHBiPh), 7.43 (d, J = 2.5, 2 H, CHAr), 7.39 (d, J = 2.5, 1 H, CHAr), 7.29− 7.27 (m, 1 H, CHAr, 1 H, CHImid), 6.88 (d, J = 1.9, 1 H, NCHImid), 6.87 (t, J = 7.6, 1 H, CHBiPh), 6.84 (d, J = 1.9, 1 H, NCHImid), 6.81 (d, J = 1.9, 1 H, NCHImid), 6.57 (d, J = 14.5, 1 H, CArCH2), 5.81 (d, J = 14.5, 1 H, CArCH2), 4.92 (d, J = 14.5, 1 H, CArCH2), 4.84 (d, J = 14.5, 1 H, CArCH2), 3.88−3.84 (m, 1 H, N(CH)Ring), 3.06−3.02 (m, 1 H, N(CH)Ring), 2.62−2.59 (m, 1 H, (CH2)Ring), 2.54−2.52 (m, 1 H, (CH2)Ring), 2.12 (s, 3 H, CBiPhCH3), 2.04 (s, 3 H, CBiPhCH3), 1.96−1.92

(m, 2 H, (CH2)Ring), 1.56−1.48 (m, 2 H, (CH2)Ring), 1.40−1.32 (m, 2 H, (CH2)Ring), 1.29 (s, 9 H, C(CH3)3), 1.27 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 162.6, 161.0, 153.5, 152.8, 143.9, 143.7, 138.1, 138.0, 137.8, 137.7, 136.3, 135.2, 134.6, 134.3, 132.2, 131.9, 130.0, 127.9, 127.7, 126.5, 126.1, 124.5, 122.5, 72.5, 71.1, 52.5, 49.8, 34.4, 34.3, 31.3 (3 C), 31.1 (3 C), 29.5, 29.2, 24.7, 24.3, 19.9, 19.7. IR (solid): ṽ = 3534, 3130, 2953, 2865, 1631, 1570, 1462, 1417, 1396, 1364, 1276, 1251, 1231, 1081, 930, 870, 834, 794, 742, 696, 621, 568, 533. HRMS (ESI) m/e: Calcd for [M − O4Cl]+ C50H54ClN6NiO6Pd: 1035.2172. Found: 1035.2195. {[1,1′-[(1R,2R)-1,2-Cyclohexandiylbis[imino-κN[5-(1,1-dimethylethyl)-2-(hydroxy-κO)-3,1-phenylen]methylen]-(Ra)-1,1′-(6,6′-dimethyl-[1,1′-biphenyl]-2,2′-diyl)bis(1H-imidazol-1yl-2(3H)-yliden)](2-)]nickel(II)}palladium(II)di(tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) (17-Ni-BArF). For the anion exchange of complex 16-Ni (15.0 mg, 15 μmol, 1 equiv) according to GP7, AgBArF (28.9 mg, 30 μmol, 2 equiv) was used. Activated complex 17-Ni-BArF (36.6 mg, 14 μmol, 92%) was isolated as a brown solid. C114H78B2F48N6NiO2Pd, MW: 2662.57 g·mol−1. Mp: 114−114 °C −1 1 (decomp.). [α]20 D = +25.0 (c = 0.1 g·dL , CH2Cl2). H NMR (500 MHz, CD2Cl2): δ = 7.96 (d, J = 7.6, 1 H, CHBiPh), 7.64 (t, J = 2.3, 16 H, CHBArF), 7.54 (t, J = 7.6, 1 H, CHBiPh), 7.46 (s, 8 H, CHBArF), 7.41 (d, J = 2.3, 2 H, CHAr), 7.36−7.27 (m, 2 H, NCH, 2 H, CHBiPh, 2 H, CHAr), 7.27 (d, J = 2.3, 1 H, CHAr), 7.18 (d, J = 7.6, 1 H, CHBiPh), 7.11 (d, J = 2.1, 1 H, NCHImid), 7.10 (t, J = 7.6, 1 H, CHBiPh), 6.77 (d, J = 2.1, 1 H, NCHImid), 6.73 (d, J = 2.1, 1 H, NCHImid), 6.68 (d, J = 2.1, 1 H, NCHImid), 6.30 (d, J = 14.5, 1 H, CArCH2), 5.60 (d, J = 14.5, 1 H, CArCH2), 4.67 (d, J = 14.5, 1 H, CArCH2), 4.62 (d, J = 14.5, 1 H, CArCH2), 3.41−3.38 (m, 1 H, N(CH)Ring), 2.95−2.91 (m, 1 H, N(CH)Ring), 2.40−2.38 (m, 2 H, (CH2)Ring), 1.99 (s, 3 H, CBiPhCH3), 1.80 (s, 3 H, CBiPhCH3), 1.88−1.83 (m, 2 H, (CH2)Ring), 1.25−1.18 (m, 4 H, (CH2)Ring), 1.16 (s, 9 H, C(CH3)3), 1.15 (s, 9 H, C(CH3)3). 13C NMR (125 MHz, CD2Cl2): δ = 162.8, 162.7, 161.7 (q, J = 50.2, 4 C), 153.2, 152.5, 145.0, 144.7, 141.6, 138.62, 138.58, 137.4, 136.4, 135.2 (b, 8 C), 134.3, 133.8, 133.6, 132.8, 131.5, 130.7, 130.21, 130.19, 129.3 (qq, J = 32.5, 3.0, 8 C), 128.5, 126.9, 126.8, 124.9 (q, J = 272.6, 8 C), 124.8, 124.7, 124.1, 123.3, 122.4, 121.2, 119.5, 117.9 (sept, J = 3.8, 4 C), 73.3, 70.9, 52.7, 50.2, 34.4, 34.3, 31.0 (3 C), 30.9 (3 C), 29.4, 29.3, 24.3, 24.2, 19.8, 19.5. IR (solid): ṽ = 2969, 2868, 1634, 1610, 1568, 1462, 1416, 1353, 1274, 1230, 1163, 1117, 1051, 1000, 929, 885, 838, 792, 744, 712, 682, 668, 639, 577, 565. HRMS (ESI) m/e: Calcd for [M − C32H12BF24]+ C50H54N6NiO2Pd(C32H12BF24): 1799.3360. Found: 1799.3384.

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ASSOCIATED CONTENT

S Supporting Information *

Further catalysis data, NMR spectra, and CIF files. This material is available free of charge via the Internet at http://pubs.acs.org.

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected] (R.P.). Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was financially supported by the Deutsche Forschungsgemeinschaft (DFG, PE 818/3-1). We thank Dipl.Chem. Martina Bubrin (Kaim group, Institut für Anorganische Chemie, Universität Stuttgart) for recording the UV−vis spectra and M.Sc. Sinja Manck for experimental contributions during a research internship in our laboratory.

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REFERENCES

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2010, 132, 4572. (c) Rit, A.; Pape, T.; Hepp, A.; Hahn, F. E. Organometallics 2011, 30, 334. (12) Synthesis of related monoaldehydes: (a) Kull, T.; Peters, R. Angew. Chem., Int. Ed. 2008, 47, 5461. (b) Kull, T.; Cabrera, J.; Peters, R. Chem.Eur. J. 2010, 16, 9132. (c) Meier, P.; Broghammer, F.; Latendorf, K.; Rauhut, G.; Peters, R. Molecules 2012, 17, 7121. (13) The Zn complex 5-Zn showed very broad signals in 1H NMR. Nevertheless, for the complexes prepared from 5-Zn, NMR spectra with sharp signals were obtained again. (14) Wang, H. M. J.; Lin, I. J. B. Organometallics 1998, 17, 972. (15) Frémont, P.; Scott, N. M.; Stevens, E. D.; Ramnial, T.; Lightbody, O. C.; Macdonald, C. L. B.; Clyburne, J. A. C.; Abernethy, C. D.; Nolan, S. P. Organometallics 2005, 24, 6301. (16) Review: Garrison, J. C.; Youngs, W. J. Chem. Rev. 2005, 105, 3978. (17) For an excellent compilation of possible structures, see ref 16. (18) Supplementary crystallographic data for 7-Ni have been deposited with the Cambridge Crystallographic Data Centre as deposition 1014558. This material is available at http://www.ccdc. cam.ac.uk/products/csd/request/. (19) Bondi, A. J. Phys. Chem. 1964, 68, 441. (20) This value refers to the torsion angle: C37 C38 C43 C44. See the Supporting Information for atom labeling. (21) Supplementary crystallographic data for 7-Pd have been deposited with the Cambridge Crystallographic Data Centre as deposition 1014559. This material is available at http://www.ccdc. cam.ac.uk/products/csd/request/. (22) This value refers to the torsion angle: C22 C23 C45 C44. See the Supporting Information for atom labeling. (23) Supplementary crystallographic data for 15-Ni have been deposited with the Cambridge Crystallographic Data Centre as deposition 1014560. This material is available at http://www.ccdc. cam.ac.uk/products/csd/request/. (24) This stands in contrast to most other literature known transmetalations of silver carbene complexes with Pd0 sources, which generally proceed with retention of the oxidation state. (25) Shibasaki et al. have recently found a positive impact of two cooperating metal centers in bimetallic salen complexes on the stereoselectivity outcome of this reaction: Kato, Y.; Furutachi, M.; Chen, Z.; Mitsunuma, H.; Matsunaga, S.; Shibasaki, M. J. Am. Chem. Soc. 2009, 131, 9168. (26) For another Ni catalyst for this reaction, see: Han, Y.-Y.; Wu, Z.-J.; Chen, W.-B.; Du, X.-L.; Zhang, X.-M.; Yuan, W.-C. Org. Lett. 2011, 13, 5064. (27) Reviews about the asymmetric synthesis of oxindoles: (a) Trost, B. M.; Brennan, M. K. Synthesis 2009, 3003. (b) Zhou, F.; Liu, Y.-L.; Zhou, J. Adv. Synth. Catal. 2010, 352, 1381. (28) Selected reviews on conjugate additions: (a) Berner, O. M.; Tedeschi, L.; Enders, D. Eur. J. Org. Chem. 2002, 1877. (b) Christoffers, J.; Baro, A. Angew. Chem., Int. Ed. 2003, 42, 1688. (c) Christoffers, J.; Koripelly, G.; Rosiak, A.; Rössle, M. Synthesis 2007, 1279. (d) Tsogoeva, S. B. Eur. J. Org. Chem. 2007, 1701. (29) The silver salt used for catalyst activation has a strong influence on the reactivity (see the Supporting Information for details). (30) Selected examples for catalytic asymmetric Conia-ene reactions: (a) Matsuzawa, A.; Mashiko, T.; Kumagai, N.; Shibasaki, M. Angew. Chem., Int. Ed. 2011, 50, 7616. (b) Tsukada, N.; Yamamoto, Y. Angew. Chem., Int. Ed. Engl. 1997, 36, 2477. (31) For a similar reaction using a Cu catalyst, see: Montel, S.; Bouyssi, D.; Balme, G. Adv. Synth. Catal. 2010, 352, 2315. (32) Selected reviews: (a) Sladojevich, F.; Dixon, D. J. In Asymmetric Synthesis II; Christmann, M., Bräse, S., Eds.; Wiley-VCH: Weinheim, Germany, 2012; pp 343−351. (b) Toullec, P. Y.; Michelet, V. Top. Curr. Chem. 2011, 302, 31. (33) Braunstein, P.; Lehner, H.; Matt, D. Inorg. Synth. 1990, 27, 218. (34) (a) Rajeswran, W. G.; Cohen, L. A. Tetrahedron 1998, 54, 11375. (b) Fournet, G.; Balme, G.; Gore, J. Tetrahedron 1991, 47, 6293. (35) Nan, G.; Rao, B.; Luo, M. ARKIVOC 2011, ii, 29. (36) Liu, J.; Chen, J.; Zhao, J.; Li, L.; Zhang, H. Synthesis 2003, 2661.

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