Article pubs.acs.org/Organometallics
Yttrium Hydride Complex Bearing CpPN/Amidinate Heteroleptic Ligands: Synthesis, Structure, and Reactivity Zhongbao Jian,†,‡,# Noa K. Hangaly,∥,# Weifeng Rong,†,‡ Zehuai Mou,†,‡ Dongtao Liu,† Shihui Li,† Alexander A. Trifonov,⊥ Jörg Sundermeyer,*,∥ and Dongmei Cui*,†,§ †
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China ‡ Graduate School of the Chinese Academy of Sciences, Beijing 100039, China § State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China ∥ Fachbereich Chemie der Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany ⊥ G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinina 49, GSP-445, 603950 Nizhny Novgorod, Russia S Supporting Information *
ABSTRACT: The reaction of the yttrium dialkyls (C5H4− PPh2N−C6H3iPr2)Y(CH2SiMe3)2(thf) (1) with an excess of N,N′-diisopropylcarbodiimide gave the yttrium monoalkyl complex (C5H4−PPh2N−C6H3iPr2)Y(CH2SiMe3)[iPrN C(CH2SiMe3)−NiPr] (2). 2 subsequently reacted with 1 equiv of PhSiH3 to generate the CpPN/amidinate heteroleptic yttrium hydride {(C5H4−PPh2N−C6H3iPr2)Y[iPrNC(CH2SiMe3)−NiPr](μ-H)}2 (3). Hydride 3 showed good reactivity toward various substrates containing unsaturated C− C, C−N, and N−N bonds, such as azobenzene, p-tolyacetylene, 1,4-bis(trimethylsilyl)-1,3-butanediyne, N,N′-diisopropylcarbodiimide, and 4-dimethylaminopyridine, affording the yttrium hydrazide complex 4 with a rare η2-Cp bonding mode, yttrium terminal alkynyl complex 5, yttrium η3-propargyl complex 6, yttrium amidinate complex 7, and yttrium 2-hydro-4dimethylaminopyridyl product 8, respectively.
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INTRODUCTION Rare-earth-metal alkyl and hydride complexes have witnessed a spectacular growth in the past three decades due to their unique reactivity and crucial role in a wide range of stoichiometric and catalytic processes.1 In particular, rareearth-metal hydrides have occupied a special important place in the area of rare-earth-metal chemistry, because of the variety of their intriguing structural and chemical properties.1c−e,h,k,l Since the discovery of the first rare-earth-metal hydride in the early 1980s,2 a large number of monohydrido, dihydrido, polyhydrido, and even terminal hydrido rare-earth-metal complexes have been synthesized and their reactivity has been studied.3−6 It is noteworthy that the ancillary ligands in these hydrides are almost focused on either cyclopentadienyl (Cp)-type ligands (Cp derivatives and constrained-geometry-configuration (CGC) ligands)3,4 or non-Cp-type ligands, such as amidopyridinate, amidinate, benzamidinate, guanidinate, salicylaldiminate, and tris(pyrazolyl)borate ligands.1d,5,6 Examples of heteroleptic rare-earth-metal hydrides remain limited;3o,7 especially, the Cp/non-Cp-type heteroleptic hydrides are scarce. Heteroleptic rare-earth-metal hydrides are of much interest, because their electronic and steric properties can be readily tuned by changing the framework of mixed ligands, © 2012 American Chemical Society
which make the resulting hydrides generate a rational balance between the kinetic stability and the high reactivity. On the other hand, as one of the Cp-type ligands, the CGCtype ancillary ligands have been widely used in the rare-earthmetal hydrides.1i,4 To date, considerable attention has been paid to these hydrides that bear the dianionic CGC ancillary ligands, such as silylene-linked cyclopentadienyl-amido ligands (CpSiN) and silylene-linked cyclopentadienyl-phosphido ligands (CpSiP), because such hydrides are electronically more unsaturated and have sterically more accessible properties and thus can be expected to show fascinating reactivity. However, those rare-earth-metal hydrides supported by the monoanionic CGC ancillary ligands, such as cyclopentadienyl-phosphazene ligands (CpPN), remain almost unexplored to date, although such CpPN-type ligands are of particular interest in comparison with the CpSiN-type and CpSiP-type ligands.8 We recently disclosed the synthesis of a series of CpPN-type rare-earth-metal dialkyl complexes.9 In this contribution, we present the reactivity of the yttrium dialkyl complex (C5H4− PPh2N−C6H3iPr2)Y(CH2SiMe3)2(thf). More remarkably, we Received: May 2, 2012 Published: June 6, 2012 4579
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Scheme 1. Synthesis of 2 by the Reaction of 1 with N,N′-Diisopropylcarbodiimide
Å) from the amidinato group in 2 are in the range of 2.304(2)− 2.462(2) Å.10b In addition, we found that 2 could not further react with an excess of N,N′-diisopropylcarbodiimide. Synthesis of Heteroleptic Yttrium Hydride Complex 3. Heteroleptic alkyl complex 2 was attempted to react with 1 equiv of PhSiH3, although it has a relatively weak reactivity. Delightful to us, the reaction readily took place at room temperature and gave the desired CpPN/amidinate heteroleptic yttrium hydride 3 in a 60% isolated yield as colorless crystalline solids (Scheme 2). 3 has good solubility in toluene, but is sparingly soluble in hexane. In addition, when 3 is stored at room temperature for 1 week, the NMR spectra indicate that it does not decompose. In the 1H NMR spectrum of 3, a sharp well-resolved triplet is observed at δ = 5.32 ppm (1JYH = 26.4 Hz), which is assignable to two Y−H hydrogen protons, thus indicating coupling of each hydrido ligand with two equivalent 89 Y nuclei.6k,m,11 The signal of hydrogen protons of 3 is shifted downfield in comparison with these triplets at δ = 2.02 ppm (1JYH = 27.0 Hz) in [(Cp)2Y(thf)(μ-H)]2,2 δ = 2.69 ppm (1JYH = 32.7 Hz) in [(2,4,7-Me3C9H4)2Y(μ-H)]2,11c and δ = 3.09 ppm (1JYH = 32.8 Hz) in [(tBuC5H4)2Y(μ-H)]211d and is close t o t h e c h e m i c a l sh i f t s o f t h e s e C p c o m p l e x e s [(C5Me4SiMe2NC6H4R)Y(thf)(μ-H)]2 (δ = 5.10 ppm, 1JYH = 28.4 Hz),4a [(C5Me4SiMe2NCMe3)Y(thf)(μ-H)]2 (δ = 5.50 ppm, 1JYH = 28.8 Hz),11b and [(C5Me4CH2SiMe2NCMe3)Y(thf)(μ-H)]2 (δ = 5.50 ppm, 1JYH = 26.8 Hz),11a but is remarkably shifted to the high field compared with the chemical shifts of non-Cp-ligated complexes [N2BFuY(thf)(μ-H)]2 (δ = 7.71 ppm, 1JYH = 27.0 Hz),11f {[(Me3Si)2NC(NiPr)2]2Y(thf)(μH)}2 (δ = 7.95 ppm, 1JYH = 26.2 Hz),6k and {[PhC(NSiMe3)2]2Y(thf)(μ-H)}2 (δ = 8.28 ppm, 1JYH = 27.6 Hz).6m Consistent with these, the 1H and 13C NMR spectra clearly show that 3 is a dimeric molecule with an internal mirror plane in the solution state. The interesting NMR spectra of 3 inspired us to study its solid-state structure, which was successfully resolved by X-ray diffraction to be a CpPN/ amidinate heteroleptic dimer {(C5H4−PPh2N−C6H3iPr2)Y[iPrNC(CH2SiMe3)−NiPr](μ-H)}2 (Figure 2). The two CpPN ligands coordinate to the two yttrium centers (Y1 and Y2) in different η5/κ1 and η5 bonding modes, respectively. The N4 atom is away from the Y2 center, and the bond length of Y1−N1 (2.519(5) Å) in 3 is slightly longer than that of Y1−N1 (2.463(5) Å) in 2. The two amidinate ligands are bonded to the two yttrium centers (Y1 and Y2) in the same η2-N,N′ coordination mode. The bond lengths of Y1−N2 (2.346(5) Å), Y1−N3 (2.358(5) Å), Y2−N5 (2.324(6) Å), and Y2−N6 (2.336(6) Å) in 3 are also close to those analogous distances in 2. In the tetranuclear Y2H2 core, the Y−H bond distances are 1.71(6), 2.29(6), 2.29(6), and 2.20(6) Å, respectively. The Y1···Y2 distance (3.631(2) Å) in 3 is slightly shorter than those in the complexes [(MeC5H4)2Y(thf)(μ-H)]2 (3.664(1) Å),2 [(1,3-Me2C5H3)2Y(thf)(μ-H)]2 (3.68(1) Å),11e {[(Me3Si)2NC-
wish to uncover a CpPN/amidinate heteroleptic yttrium hydride and its reactions with unsaturated substrates, such as azobenzene, p-tolyacetylene, 1,4-bis(trimethylsilyl)-1,3-butanediyne, N,N′-diisopropylcarbodiimide, and 4-dimethylaminopyridine, to probe the fundamental reactivity of this new Cp/nonCp heteroleptic hydride toward unsaturated C−C, C−N, and N−N bonds.
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RESULTS AND DISCUSSION
Reactivity of Yttrium Dialkyl Complex 1. The yttrium dialkyl complex 1 was synthesized as reported recently by us.9 Addition of 1 equiv of N,N′-diisopropylcarbodiimide to a mixture solution of hexane and toluene of 1 resulted in the formation of the yttrium monoalkyl complex (C5H4−PPh2 N−C6H3iPr2)Y(CH2SiMe3)[iPrNC(CH2SiMe3)−NiPr] (2) as colorless solids (75%) (Scheme 1). The 1H NMR spectrum of 2 shows two broad singlets at δ = −0.26 to −0.11 ppm and δ = 1.77 ppm arising from the Y−CH2SiMe3 methylene protons and the newly generated CH2SiMe3 methylene protons, respectively. Meanwhile, one singlet is also observed at δ = 176.33 ppm in the 13C NMR spectrum, which is assignable to the carbon proton of the amidinato group (NC−N).10a The molecular structure of 2 was determined by X-ray diffraction to be a CpPN/amidinate heteroleptic monomer (Figure 1). The bond lengths of Y1−N2 (2.367(5) Å) and Y1−N3 (2.315(5)
Figure 1. X-ray structure of 2 (40% probability of thermal ellipsoids). Hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and angles (deg): Y1−Cpcent 2.504, Y1−C41 2.419(7), Y1−N1 2.463(5), Y1−N2 2.367(5), Y1−N3 2.315(5); Cpcent−Y1−N1 88.3, N2−Y1− N3 57.2(2) (CpCent is the centroid of the cyclopentadienyl ring). 4580
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Scheme 2. Synthesis of the CpPN/Amidinate Heteroleptic Yttrium Hydride 3
formed PhNNHPh hydrogen proton. Surprisingly, we unexpectedly observe a singlet at δ = 5.46 ppm in the 1H NMR spectrum of 4, which correlates with the signal at δ = 67.83 ppm in the 13C NMR spectrum. This unusual signal may be assigned to the C5H4 group, although it is significantly shifted upfield in comparison with these chemical shifts at δ = 7.06− 7.17 ppm in 3. The coordination geometry of 4 could not be understood on the basis of the above NMR information, but was confirmed by X-ray diffraction to be [(η2-C5H4)−PPh2 N−C6H3iPr2]Y[iPrNC(CH2SiMe3)−NiPr](η2-PhNNHPh) (Figure 3). The crystal structure of 4 contains a free PhN NPh molecule. The CpPN ligand coordinates to the Y3+ ion in a η2/κ1 mode. The bond length of Y1−C2 (2.703(3) Å) is unexpectedly shorter than that of Y1−C1 (2.778(3) Å), but both fall in the range of the Y−C(Cp) bond.3h,14 However, the bond lengths of Y1···C3 (3.345 Å), Y1···C4 (3.729 Å), and Y1···C5 (3.424 Å) exceed the normal range, suggesting that the C3, C4, and C5 atoms are away from the metal center. Furthermore, these bond distances of C1−C2 (1.433(4) Å), C2−C3 (1.385(5) Å), C3−C4 (1.401(5) Å), C4−C5 (1.375(5) Å), and C1−C5 (1.414(5) Å) indicate that the electrons tend to delocalize within the Cp framework. Therefore, the atoms C1, C2, C3, C4, and C5 form a plane, and the P1 on the C1 atom almost lies in the plane, but the H2 on the C2 atom deviates from the plane by 0.53 Å. As far as we are aware, this type of η2 bonding mode of the delocalized Cp moiety in 4 is extremely rare, which has been found in a tris(cyclopentadienyl)titanium (η5-C5H5)2Ti(η2-C5H5).15 On the other hand, the (PhNNHPh)− monoanion is bonded to the central metal in a η2-N,N′ bidentate mode. The bond length of Y1−N4 (2.209(3) Å) is remarkably shorter than that of Y1− N5 (2.417(3) Å), indicating that a hydrogen atom H65 is located on N5. The N4−N5 bond distance of the hydrazido ligand, 1.427(4) Å, is slightly shorter than those analogous distances in (η5-C5Me5)2Sm(PhNNHPh)(thf) (1.443(7) Å)13 and the yttrium hydrazide (1.441(2) Å),7a but remarkably longer than that of the N−N double bond of PhNNPh (1.247 Å).16 The interesting structure of 4 encourages us to further study the reaction of heteroleptic hydride 3 with an unsaturated substrate containing a C−C triple bond. The reactions of rareearth-metal alkyl or hydride complexes with terminal alkynes are of particular interest, because the resulting alkynyl complexes adopt various bonding modes ranging from terminal alkynyls to asymmetric alkynyl and coupled butatrienediyl bridging ligands in dimeric complexes.6j,l,17,18 Herein, the hydride 3 reacted with 2 equiv of the terminal alkyne ptolyacetylene in hexane and toluene at room temperature to yield the yttrium alkynyl complex 5 as colorless crystalline solids (Scheme 3). There is one singlet appearing at δ = 2.10
Figure 2. X-ray structure of the yttrium hydride 3 (40% probability of thermal ellipsoids). Hydrogen atoms are partly omitted for clarity. Isopropyl groups on CpPN/amidinate ligands have been also omitted. Selected bond lengths (Å) and angles (deg): Y1−Cpcent1 2.472, Y2− Cpcent2 2.442, Y1−N1 2.519(5), Y1−N2 2.346(5), Y1−N3 2.358(5), Y2−N5 2.324(6), Y2−N6 2.336(6), Y1−H88 1.71(6), Y1−H89 2.29(6), Y2−H88 2.29(6), Y2−H89 2.20(6), Y1···Y2 3.631(2); Cpcent1−Y1−N1 88.1 (CpCent1 and CpCent2 are the centroids of the cyclopentadienyl ring).
(NiPr)2]2Y(thf)(μ-H)}2 (3.683(5) Å),6k and [(C5Me4CH2SiMe2NCMe3)Y(thf)(μ-H)]2 (3.709(8) Å).11a Reactivity of Hydride 3 toward Unsaturated Substrates. We first studied the reactivity of heteroleptic hydride 3 with azobenzene containing a NN bond. To date, the reactions of divalent rare-earth-metal complexes with azobenzene have been extensively reported,12 but examples on the reactions of rare-earth-metal hydrides with azobenzene are rare.7a,13 Evans and co-workers have reported the reaction of [(η5-C5Me5)2Sm(μ-H)]2 with azobenzene, affording the samarium hydrazide (η5-C5Me5)2Sm(PhNNHPh)(thf).13 Very recently, Chen and co-workers also synthesized a yttrium hydrazide through the reaction of the yttrium anilido hydride with azobenzene.7a Herein, the reaction of 3 with 4 equiv of azobenzene in hexane and toluene at room temperature readily yielded the yttrium hydrazide 4 as yellow crystalline solids in a 49% isolated yield (Scheme 3). In the 1H NMR spectrum of 4, the Y−H signal disappears; instead, a slightly broad singlet appears at δ = 3.58 ppm, which can be attributed to the newly 4581
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Scheme 3. Reactivity of the Hydride 3 toward Unsaturated Substrates
ppm in the 1H NMR spectrum of 5, which can be attributed to the hydrogen protons from the CCPhMe group. Notably, two doublets are obviously observed at δ = 142.25 ppm (1JYC =
67.5 Hz) and 107.44 ppm (2JYC = 13.5 Hz) in the 13C NMR spectrum, belonging to the α- and β-carbons of the CCPhMe group, respectively. This is consistent with these chemical shifts reported in yttrium terminal alkynyl complexes (TptBu,Me)Y(CCPh)2 (143.77 ppm, d, 1JYC = 59.3 Hz; and 102.22 ppm, d, 2JYC = 12.05 Hz)17 and (C5Me5)2Y(CCPh)(OEt2) (146.95 ppm, d, 1JYC = 70.9 Hz; and 109.59 ppm, d, 2JYC = 12.05 Hz),18i suggesting that 5 is a terminal alkynyl complex. To further confirm its structure, single crystals of 5 suitable for an X-ray structure determination were obtained by recrystallization from hexane and toluene at room temperature. 5 was clearly established by the X-ray analysis to be (C5H4−PPh2 N−C 6 H 3 i Pr 2 )Y[ i PrNC(CH 2 SiMe 3 )−N i Pr][CCPh(pMe)] (see the Supporting Information, Figure S1).19 The reaction of hydride 3 with a diyne containing conjugated triple bonds was further studied. Reports on the reactions of rare-earth-metal hydrides with diynes are rare.3n,20 Takats and co-workers have explored the reaction of [(TptBu,Me)Yb(μ-H)]2 with 1,4-bis(trimethylsilyl)-1,3-butanediyne, giving a propargyl complex.20 Hou and co-workers also introduced the reaction of [(C5Me4SiMe3)Y(μ-H)2]4(thf) with 1,4-bis(trimethylsilyl)-1,3butanediyne, affording a butene-tetraanion complex.3n On the basis of these pioneer works, the reaction of 3 with 2 equiv of 1,4-bis(trimethylsilyl)-1,3-butanediyne at room temperature produced the complex 6 as a pale yellow oil (Scheme 3). The oil was extremely soluble in hexane even at −30 °C, so we could not isolate the single crystals of 6. Fortunately, we could confirm its structure from the NMR information. The absence of the hydride signal at δ = 5.32 ppm indicates the consumption of hydride 3. In addition to the characteristic CpPN and amidinate ligands signals, one singlet appearing at δ = 7.14 ppm
Figure 3. X-ray structure of 4 (40% probability of thermal ellipsoids). Hydrogen atoms are partly omitted for clarity. Selected bond lengths (Å) and angles (deg): Y1−C1 2.778(3), Y1−C2 2.703(3), Y1···C3 3.345, Y1···C4 3.729, Y1···C5 3.424, Y1−N1 2.417(3), Y1−N2 2.314(3), Y1−N3 2.341(3), Y1−N4 2.209(3), Y1−N5 2.417(3), C1−C2 1.433(4), C2−C3 1.385(5), C3−C4 1.401(5), C4−C5 1.375(5), C1−C5 1.414(5), N4−N5 1.427(4); N4−Y1−N5 356(1). 4582
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in the 1H NMR spectrum, which correlates with one doublet at δ = 147.84 ppm (2JYC = 3.0 Hz) in the 13C NMR spectrum, and two different SiMe3 signals at δ = 0.48 and 0.56 ppm suggest the formation of an olefinic bond that comes from addition of Y−H to one of the two triple bonds. Compared to the related chemical shift reported in the ytterbium propargyl complex (δ = 7.65 ppm (1H) and δ = 152.5 ppm (13C)),20 this signal at δ = 7.14 ppm can be assigned to one hydrogen proton of the C CH(SiMe3) group. Of particular note is that the doublet appearing at δ = 205.28 ppm with the coupling constant of 1JYC = 46.5 Hz in the 13C NMR spectrum is suggestive of an η3propargyl group, which has been observed at δ = 217.1 ppm in the ytterbium propargyl complex.20 In the aforementioned text, the Cp/amidinate heteroleptic monoalkyl complex 2 cannot react with an excess of N,N′diisopropylcarbodiimide. In contrast, the reaction of the Cp/ amidinate heteroleptic hydride 3 with 2 equiv of N,N′diisopropylcarbodiimide at room temperature readily yielded the yttrium amidinate complex 7 as colorless crystalline solids in a 85% high yield (Scheme 3). There is an obvious doublet appearing at δ = 8.33 ppm (3JYH = 6.0 Hz) in the 1H NMR spectrum of 7, which can be attributed to the NCH−N hydrogen signal of the amidinate ligand.7a The molecular structure of 7 was confirmed by X-ray diffraction as (C5H4− PPh2N−C6H3iPr2)Y[iPrNC(CH2SiMe3)−NiPr](iPrN CH−NiPr) (Figure 4). In the solid-state structure of 7, two
isopropyls on one amidinate framework adopt a cis conformation, and two isopropyls on another amidinate framework locate in a trans conformation. The reactions of rare-earth-metal hydrides with pyridine or its derivatives, which can form three products, dihydrogen elimination (I),17i,21 1,2-insertion (II),4a,6j,17j,22 and 1,4insertion (III),22,23 have attracted much attention (Chart 1). Chart 1. Three Products Obtained by the Reaction of RareEarth-Metal Hydride with Pyridine
Therefore, the reaction of hydride 3 with 4-dimethylaminopyridine (DMAP) was also performed. Hydride 3 reacted with 4 equiv of DMAP to afford the 1,2-insertion product 8 as yellow crystalline solids (Scheme 3). The X-ray diffraction analysis revealed its structure as a 2-hydro-4-dimethylaminopyridyl complex (C5H4−PPh2N−C6H3iPr2)Y[iPrNC(CH2SiMe3)−NiPr][η1-NC5H5(p-NMe2)](DMAP) formed by 1,2-insertion of DMAP into the Y−H bond of 3 (Figure 5).
Figure 5. X-ray structure of 8 (40% probability of thermal ellipsoids). Hydrogen atoms are partly omitted for clarity. Selected bond lengths (Å) and angles (deg): Y1−N2 2.357(5), Y1−N3 2.321(4), Y1−N4 2.222(5), Y1−N6 2.467(5), N4−C41 1.418(8), C41−C42 1.425(9), N6−C48 1.342(7), N6−C52 1.352(7); N4−C41−C42 116.8(6), N6− C48−C49 124.5(6), N6−C52−C51 124.4(6).
Figure 4. X-ray structure of 7 (40% probability of thermal ellipsoids). Hydrogen atoms are partly omitted for clarity. Selected bond lengths (Å) and angles (deg): Y1−N1 2.594(2), Y1−N2 2.335(2), Y1−N3 2.406(2), Y1−N4 2.396(2), Y1−N5 2.394(2), N2−C30 1.331(3), N3−C30 1.337(4), N4−C41 1.315(4), N5−C41 1.322(4); N2−Y1− N3 56.1(8), N4−Y1−N5 56.7(8).
The NMR spectroscopy further confirmed the structure. Five separate signals assigned to the 2-hydro-4-dimethylaminopyridyl ligand are observed in the 1H NMR spectrum of 8.4a,6j,18j,22 The NMe2 hydrogen protons show one singlet at δ = 2.75 ppm. A multiplet is found at δ = 4.17−4.18 ppm for the proton in the 3-NC5H5(p-NMe2) position. Two hydrogen protons of the methylene group in the 2-NC5H5(p-NMe2) position give rise to a doublet at δ = 4.57 ppm with a coupling constant of 2JYH = 36.6 Hz. A doublet of doublets at δ = 5.23 ppm is assigned to the hydrogen proton in the 5-NC5H5(p-NMe2) position. The hydrogen proton in the 6-NC5H5(p-NMe2) position is
different amidinate ligands coordinate to the yttrium center in the same η2-N,N′ bidentate mode with the Y−N bond lengths of 2.335(2) and 2.406(2)Å, and 2.396(2) and 2.394(2) Å, respectively, which are obviously shorter than the length of the coordination Y1−N1 bond (2.594(2) Å). The bond lengths of N2−C30 (1.331(3) Å) and N3−C30 (1.337(4) Å) are almost equal, and so are the bond lengths of N4−C41 (1.315(4) Å) and N5−C41 (1.322(4) Å), indicating that the electrons delocalize in the amidinate framework. Interestingly, two 4583
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observed at δ = 6.06 ppm as a doublet (3JHH = 6.0 Hz). Notably, the signals from the coordinated DMAP molecule are also found. In the solid-state structure of 8, the 2-hydro-4dimethylaminopyridyl ligand is bonded to the yttrium center in the η1-N mode. One DMAP molecule coordinates to the yttrium center, which leads to the leaving of the N1 atom of the CpPN ligand from the metal center. The length of the Y1−N4 covalent bond (2.222(5) Å) is comparable to the lengths of the analogous Y−N bonds in Y(η5-C5Me4CH2SiMe2NPh-κN)(η1NC5H6)(py)2 (2.294(5) Å)4a and (DADMB)Y(η1-NC5H6)(py)2 (2.281(5) Å),22a but is much shorter than the length of the coordination bond Y1−N6 (2.467(5) Å). The length of the N4−C41 single bond (1.418(8) Å) is almost equal to that of the N−C single bond (1.424(8) Å) in (DADMB)Y(η1NC5H6)(py)2,22a but is obviously longer than the lengths of these N6−C48 (1.342(7) Å) and N6−C52 (1.352(7) Å) bonds in the delocalized DMAP framework. In addition, the N4− C41−C42 angle of 116.8(6)° in 8 is close to the corresponding angle (115.2(6)°) in (DADMB)Y(η1-NC5H6)(py)2,22a but is different from these angles of N6−C48−C49 (124.5(6)°) and N6−C52−C51 (124.4(6)°) of the DMAP molecule.
0.71073 Å). The determination of crystal class and unit cell parameters was carried out by the SMART program package.24 The raw frame data were processed using SAINT and SADABS to yield the reflection data file.25 The structures were solved by using the SHELXTL program.26 Refinement was performed on F2 anisotropically for all non-hydrogen atoms by the full-matrix least-squares method. The hydrogen atoms were placed at the calculated positions and were included in the structure calculation without further refinement of the parameters. The two bridging hydrogen atoms in complex 3 have been refined anisotropically. Synthesis of the Complex (C5H4−PPh2N−C6H3iPr2)Y(CH2SiMe3)[iPrNC(CH2SiMe3)−NiPr] (2). Under a nitrogen atmosphere, to a mixture solution of hexane and toluene (10 mL) of 1 (0.380 g, 0.5 mmol) was added 1 equiv of N,N′diisopropylcarbodiimide (0.063 g, 0.5 mmol) slowly at room temperature. The mixture was stirred for 4 h to afford a colorless solution. Evaporation of the solvent left 2 as colorless crystalline solids (0.307 g, 75%). Recrystallization from hexane and toluene at −30 °C gave single crystals suitable for X-ray analysis. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ −0.26 and −0.11 (overlapped br s, 2H, YCH2SiMe3), 0.09 (s, 9H, CH2SiMe3), 0.42 (br s, 12H, CH(CH3)2), 0.49 (s, 9H, YCH2SiMe3), 1.34 (s, 12H, CH(CH3)2), 1.77 (br s, 2H, CH2SiMe3), 3.04 (br s, 1H, CH(CH3)2), 3.35 (br s, 2H, CH(CH3)2), 3.75 (br s, 1H, CH(CH3)2), 6.71−7.05 (m, 13H, Ph-H and Ar-H and C5H4), 7.46 (br s, 2H, Ph-H), 7.79 ppm (br s, 2H, Ph-H). 13C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ 0.09 (s, 3C, CH2SiMe3), 4.93 (s, 3C, CH2SiMe3), 16.92 (s, 1C, CH2SiMe3), 23.30−25.75 and 28.80−29.27 (very br m, 8C, CH(CH3)2), 26.53 (br s, 2C, CH(CH3)2), 29.68 (d, 1JYC = 43.5 Hz, 1C, YCH2SiMe3), 47.95 (br s, 2C, NCH(CH3)2), 95.77 (d, 1JPC = 124.5 Hz, 1C, ipso-C5H4), 110.03 (br s, 1C, C5H4), 114.65 (br s, 1C, C5H4), 120.83 (br s, 2C, C5H4), 124.14 (d, 5JPC = 4.5 Hz, 1C, Ar-C), 124.46 (d, 4JPC = 3.0 Hz, 2C, ArC), 128.52 (d, 2JPC = 12.0 Hz, 4C, Ph-C), 132.19 (s, 4C, Ph-C), 133.27 (d, 3JPC = 7.5 Hz, 4C, Ph-C), 144.64 (d, 2JPC = 9.0 Hz, 1C, ipso-Ar-C), 145.38 (d, 3JPC = 6.0 Hz, 2C, ipso-Ar-C), 176.33 ppm (s, 1C, NC− N). Anal. Calcd for C44H67N3PSi2Y (%): C, 64.92; H, 8.30; N, 5.16. Found: C, 65.32; H, 8.42; N, 5.03. Synthesis of the Hydride {(C5H4−PPh2N−C6H3iPr2)Y[iPrN C(CH2SiMe3)−NiPr](μ-H)}2 (3). Under a nitrogen atmosphere, to a mixture solution of hexane and toluene (10 mL) of 2 (0.407 g, 0.5 mmol) was added 1 equiv of phenylsilane (0.054 g, 0.5 mmol) slowly at room temperature. The mixture was stirred for 4 h to afford a colorless solution. Evaporation of the solvent left 3 as colorless crystalline solids (0.218 g, 60%). Recrystallization from hexane and toluene at −30 °C gave single crystals suitable for X-ray analysis. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ 0.17 (s, 18H, CH2SiMe3), 1.06 (d, 3JHH = 6.0 Hz, 24H, CH(CH3)2), 1.12 (br s, 12H, CH(CH3)2), 1.34 (d, 3JHH = 6.0 Hz, 12H, CH(CH3)2), 1.98 (s, 4H, CH2SiMe3), 3.44−3.46 (sept, 4H, CH(CH3)2), 3.70−3.74 (sept, 4H, CH(CH3)2), 5.32 (t, 1JYH = 26.4 Hz, 2H, YH), 7.06−7.17 (m, 26H, Ph-H and Ar-H and C5H4), 7.62 ppm (br s, 8H, Ph-H). 13C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ 0.57 (s, 6C, CH2SiMe3), 17.20 (s, 2C, CH2SiMe3), 24.74 (s, 8C, CH(CH3)2), 25.85 (s, 4C, CH(CH3)2), 27.41 (s, 4C, CH(CH3)2), 28.81 (s, 4C, CH(CH3)2), 47.87 (s, 4C, NCH(CH3)2), 106.82 (d, 1JPC = 132.0 Hz, 2C, ipsoC5H4), 116.13 (br s, 4C, C5H4), 117.84 (br s, 4C, C5H4), 121.68 (s, 2C, Ar-C), 124.46 (s, 4C, Ar-C), 128.43 (s, 4C, Ph-C), 131.17 (s, 8C, Ph-C), 133.03 (d, 3JPC = 9.0 Hz, 8C, Ph-C), 133.60 (br s, 2C, Ph-C), 134.17 (br s, 2C, Ph-C), 144.46 (d, 3JPC = 6.0 Hz, 4C, ipso-Ar-C), 145.23 (d, 2JPC = 6.0 Hz, 2C, ipso-Ar-C), 174.52 ppm (s, 2C, NC− N). Anal. Calcd for C80H114N6P2Si2Y2 (%): C, 66.01; H, 7.89; N, 5.77. Found: C, 66.45; H, 8.03; N, 5.62. Synthesis of the Complex [(η2-C5H4)−PPh2N−C6H3iPr2]Y[iPrNC(CH2SiMe3)−NiPr][η2(N,N′)-PhNNHPh] (4). Under a nitrogen atmosphere, to a mixture solution of hexane and toluene (5 mL) of 3 (0.146 g, 0.1 mmol) was added 4 equiv of azobenzene (0.072 g, 0.4 mmol) slowly at room temperature. The mixture was stirred for 12 h to afford a yellow solution. Evaporation of the solvent left 4 as yellow crystalline solids (0.088 g, 49%). Recrystallization from hexane and toluene at room temperature gave single crystals suitable for X-ray
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CONCLUSIONS We have demonstrated the reaction of the yttrium dialkyls with N,N′-diisopropylcarbodiimide. Strikingly, the CpPN/amidinate heteroleptic yttrium hydride was synthesized. The NMR and Xray diffraction analyses showed that the hydride contains a tetranuclear Y2H2 core. The reactivity of this new class of hydride with substrates containing unsaturated C−C, C−N, and N−N bonds was probed. Reaction of azobenzene with the hydride afforded the yttrium hydrazide, in which the CpPN ligand coordinates to the Y3+ ion in a rare η2/κ1 mode. Protonolysis of the hydride with p-tolyacetylene gave the yttrium terminal alkynyl complex. The addition of the Y−H bond of the hydride across one CC bond of 1,4bis(trimethylsilyl)-1,3-butanediyne yielded the yttrium η3propargyl complex. In addition, the hydride reacted with N,N′-diisopropylcarbodiimide to generate the yttrium amidinate complex. The 1,2-insertion reaction of the hydride with 4dimethylaminopyridine produced the yttrium 2-hydro-4dimethylaminopyridyl product.
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EXPERIMENTAL SECTION
General Procedures and Materials. All manipulations were performed under a nitrogen atmosphere using standard Schlenk techniques or an MBraun glovebox. All solvents were purified from the MBraun SPS system. Samples of yttrium complexes for NMR spectroscopic measurements were prepared in the glovebox by use of NMR tubes sealed by paraffin film. 1H and 13C NMR spectra were recorded on a Bruker AV600 (FT, 600 MHz for 1H; 150 MHz for 13 C) spectrometer. NMR assignments were confirmed by 1H−1H COSY and 1H−13C HMQC experiments when necessary. Elemental analysis was performed at the National Analytical Research Centre of Changchun Institute of Applied Chemistry (CIAC). N,N′-Diisopropylcarbodiimide and phenylsilane were dried over CaH2 under stirring for 24 h and distilled under reduced pressure before use. Azobenzene, p-tolyacetylene, 1,4-bis(trimethylsilyl)-1,3-butanediyne, and 4-dimethylaminopyridine (DMAP) were purchased from Aldrich and used without further purification. The yttrium dialkyl complex 1 was synthesized as reported previously by us.9 X-ray Crystallographic Studies. Crystals for X-ray analysis were obtained as described in the preparations. The crystals were manipulated in a glovebox. Data collections were performed at −88.5 °C on a Bruker SMART APEX diffractometer with a CCD area detector, using graphite-monochromated Mo Kα radiation (λ = 4584
dx.doi.org/10.1021/om3003703 | Organometallics 2012, 31, 4579−4587
Organometallics
Article
analysis. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ −0.07 (s, 9H, CH2SiMe3), 0.72 (d, 3JHH = 6.0 Hz, 9H, CH(CH3)2), 0.98−1.28 (m, 9H, CH(CH3)2), 1.42 (d, 3JHH = 6.0 Hz, 6H, CH(CH3)2), 1.56 (d, 3 JYH = 12.0 Hz, 2H, CH2SiMe3), 3.09 (br s, 1H, CH(CH3)2), 3.29 (br s, 1H, CH(CH3)2), 3.58 (br s, 1H, PhNNHPh), 3.72 (br s, 2H, CH(CH3)2), 5.46 (s, 1H, C5H4−Y), 6.37 (br s, 1H, C5H4), 6.76 (t, 3 JHH = 3.0 Hz, 2H, C5H4), 6.81−7.62 (m, 19H, Ph-H and Ar-H), 7.62 ppm (br s, 4H, Ph-H). 13C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ −0.04 (s, 3C, CH2SiMe3), 16.84 (s, 1C, CH2SiMe3), 24.23 (br s, 2C, CH(CH3)2), 24.96 (s, 2C, CH(CH3)2), 25.18 (br s, 2C, CH(CH3)2), 25.82 (br s, 2C, CH(CH3)2), 27.20 (s, 1C, CH(CH3)2), 29.13 (br s, 1C, CH(CH3)2), 47.75 (s, 2C, NCH(CH3)2), 67.83 (s, 1C, C5H4−Y), 115.16, 117.24, 122.41, 123.36, 124.15, 124.47, 129.25, 129.64, 131.13, 131.89, 131.98, 133.36, 133.72, 145.57, 149.81, 153.28, 155.92 (34C, C5H4 and Ph-C and Ar-C), 175.57 ppm (s, 1C, NC− N). Anal. Calcd for C52H67N5PSiY (%): C, 68.63; H, 7.42; N, 7.70. Found: C, 69.14; H, 7.54; N, 7.56. Synthesis of the Complex (C5H4−PPh2N−C6H3iPr2)Y[iPrNC(CH2SiMe3)−NiPr][CCPh(p-Me)] (5). Under a nitrogen atmosphere, to a mixture solution of hexane and toluene (5 mL) of 3 (0.146 g, 0.1 mmol) was added 2 equiv of p-tolyacetylene (0.023 g, 0.2 mmol) slowly at room temperature. The mixture was stirred for 3 h to afford a colorless solution. Evaporation of the solvent left 5 as colorless crystalline solids (0.095 g, 57%). Recrystallization from hexane and toluene at room temperature gave single crystals suitable for X-ray analysis. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ 0.13 (s, 9H, CH2SiMe3), 1.06 (s, 6H, CH(CH3)2), 0.89−1.35 (m, 18H, CH(CH3)2), 1.77 (s, 2H, CH2SiMe3), 2.10 (s, 3H, CCPhCH3), 3.02− 3.80 (m, 4H, CH(CH3)2), 6.98−7.16 (m, 16H, Ph-H and Ar-H and C5H4), 7.58−8.16 ppm (m, 5H, Ar-H and Ph-H). 13C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ −0.09 (s, 3C, CH2SiMe3), 16.41 (s, 1C, CH2SiMe3), 21.35 (s, 1C, CCPhCH3), 24.29 (br s, 4C, CH(CH3)2), 25.90 (br s, 4C, CH(CH3)2), 29.28 (br s, 2C, CH(CH3)2), 47.99 (s, 2C, NCH(CH3)2), 95.81 (d, 1JPC = 123.0 Hz, 1C, ipso-C5H4), 107.44 (d, 2JYC = 13.5 Hz, 1C, YCC), 124.13 (d, 2 JPC = 3.0 Hz, 2C, C5H4), 124.46 (s, 2C, C5H4), 125.66, 129.12, 131.94, 132.23, 133.59, 135.17 (s, 17C, Ph-C and Ar-C), 128.59 (d, 3 JPC = 12.0 Hz, 4C, Ph-C), 142.25 (d, 1JYC = 67.5 Hz, 1C, YCC), 144.46 (d, 2JPC = 9.0 Hz, 1C, ipso-Ar-C), 145.34 (d, 3JPC = 6.0 Hz, 2C, ipso-Ar-C), 176.25 ppm (s, 1C, NC−N). Anal. Calcd for C49H63N3PSiY (%): C, 69.90; H, 7.54; N, 4.99. Found: C, 70.32; H, 7.67; N, 4.87. Synthesis of the Complex (C5H4−PPh2N−C6H3iPr2)Y[ i PrNC(CH 2 SiMe 3 )−N i Pr][(Me 3 Si)CHC−CCSiMe 3 ] (6). Under a nitrogen atmosphere, to a mixture solution of hexane and toluene (5 mL) of 3 (0.146 g, 0.1 mmol) was added 2 equiv of 1,4bis(trimethylsilyl)-1,3-butanediyne (0.039 g, 0.2 mmol) slowly at room temperature. The mixture was stirred for 3 h to afford a pale yellow solution. Evaporation of the solvent left 6 as a pale yellow oil (0.155 g, 84%). The oil was extremely soluble in hexane even at −30 °C, so we could not isolate the single crystals. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ 0.06 (s, 9H, SiMe3), 0.48 (s, 9H, SiMe3), 0.56 (s, 9H, SiMe3), 1.25−1.33 (m, 12H, CH(CH3)2), 1.71 (s, 2H, CH2SiMe3), 3.44−3.46 (sept, 4H, CH(CH3)2), 3.32 (br s, 4H, CH(CH3)2), 6.77 (s, 2H, C5H4), 7.01−7.16 (m, 11H, Ph-H and Ar-H and C5H4), 7.14 (s, 1H, CCH(SiMe3)), 7.74 ppm (br s, 4H, Ph-H). 13C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ 0.08 (s, 3C, SiMe3), 0.23 (s, 3C, SiMe3), 1.26 (s, 3C, SiMe3), 16.82 (s, 2C, CH2SiMe3), 24.83 (br s, 4C, CH(CH3)2), 26.62 (s, 4C, CH(CH3)2), 29.13 (s, 2C, CH(CH3)2), 47.98 (s, 2C, NCH(CH3)2), 95.76 (d, 1JPC = 133.5 Hz, 1C, ipso-C5H4), 116.30 (s, 2C, C5H4), 116.75 (s, 2C, C5H4), 124.12 (s, 1C, Ar-C), 124.48 (s, 2C, Ar-C), 128.54 (s, 4C, Ph-C), 128.62 (s, 4C, Ph-C), 132.12 (s, 2C, Ph-C), 133.55 (s, 2C, Ph-C), 144.53 (d, 3JPC = 9.0 Hz, 1C, ipso-Ar-C), 145.45 (d, 3JPC = 6.0 Hz, 2C, ipso-Ar-C), 147.84 (d, 2 JYC = 3.0 Hz, 1C, CCH(SiMe3)), 176.16 (s, 1C, NC−N), 205.28 ppm (d, 1C, 1JYC = 46.5 Hz, propargyl-C). Anal. Calcd for C50H75N3PSi3Y (%): C, 65.11; H, 8.20; N, 4.56. Found: C, 65.54; H, 8.37; N, 4.45. Synthesis of the Complex (C5H4−PPh2N−C6H3iPr2)Y[iPrNC(CH2SiMe3)−NiPr](iPrNCH−NiPr) (7). Under a nitrogen
atmosphere, to a mixture solution of hexane and toluene (5 mL) of 3 (0.146 g, 0.1 mmol) was added 2 equiv of N,N′-diisopropylcarbodiimide (0.025 g, 0.2 mmol) slowly at room temperature. The mixture was stirred for 2 h to afford a colorless solution. Evaporation of the solvent left 7 as colorless crystalline solids (0.145 g, 85%). Recrystallization from hexane and toluene at room temperature gave single crystals suitable for X-ray analysis. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ 0.13 (s, 9H, CH2SiMe3), 0.94 (d, 3JHH = 12.0 Hz, 12H, CH(CH3)2), 1.24 (d, 3JHH = 6.0 Hz, 12H, CH(CH3)2), 1.27 (d, 3 JHH = 6.0 Hz, 12H, CH(CH3)2), 1.87 (s, 2H, CH2SiMe3), 3.43−3.52 (m, 4H, CH(CH3)2), 3.71−3.78 (sept, 2H, CH(CH3)2), 6.82−6.84 (quart, 2H, C5H4), 6.98−7.01 (m, 4H, Ph-H), 7.03−7.09 (m, 5H, C5H4 and Ph-H and Ar-H), 7.13 (d, 3JHH = 6.0 Hz, 2H, Ar-H), 7.56− 7.59 (m, 4H, Ph-H), 8.33 ppm (d, 3JYH = 6.0 Hz, 1H, NCH−N). 13 C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ 0.36 (s, 3C, CH2SiMe3), 17.74 (s, 1C, CH2SiMe3), 24.95 (s, 4C, CH(CH3)2), 25.75 (br s, 4C, CH(CH3)2), 26.07 (s, 4C, CH(CH3)2), 28.37 (br s, 2C, CH(CH3)2), 47.76 (s, 2C, NCH(CH3)2), 52.16 (s, 2C, NCH(CH3)2), 103.47 (d, 1JPC = 135.0 Hz, 1C, ipso-C5H4), 116.33 (d, 2JPC = 13.5 Hz, 2C, C5H4), 116.75 (d, 3JPC = 12.0 Hz, 2C, C5H4), 121.98 (d, 5JPC = 3.0 Hz, 1C, Ar-C), 123.94 (d, 4JPC = 1.5 Hz, 2C, ArC), 131.36 (s, 4C, Ph-C), 133.16 (s, 2C, Ph-C), 133.27 (d, 3JPC = 7.5 Hz, 4C, Ph-C), 133.76 (s, 2C, Ph-C), 144.85 (d, 3JPC = 6.0 Hz, 2C, ipso-Ar-C), 145.12 (d, 2JPC = 7.5 Hz, 1C, ipso-Ar-C), 166.95 (s, 1C, NCH−N), 174.81 ppm (s, 1C, NC−N). Anal. Calcd for C47H71N5PSiY (%): C, 66.10; H, 8.38; N, 8.20. Found: C, 66.54; H, 8.50; N, 8.08. Synthesis of the Complex (C5H4−PPh2N−C6H3iPr2)Y[ i PrNC(CH 2 SiMe 3 )−N i Pr][η 1 -NC 5 H 5 (p-NMe 2 )](DMAP) (8). Under a nitrogen atmosphere, to a mixture solution of hexane and toluene (5 mL) of 3 (0.146 g, 0.1 mmol) was added 4 equiv of 4dimethylaminopyridine (0.050 g, 0.4 mmol) slowly at room temperature. The mixture was stirred for 2 h to afford a yellow solution. Evaporation of the solvent left 8 as yellow crystalline solids (0.112 g, 58%). Recrystallization from hexane and toluene at room temperature gave single crystals suitable for X-ray analysis. 1H NMR (600 MHz, C6D6, 7.16 ppm, 25 °C): δ 0.18 (s, 9H, CH2SiMe3), 0.70 (br s, 6H, CH(CH3)2), 1.02 (br s, 12H, CH(CH3)2), 1.35 (br s, 6H, CH(CH3)2), 1.99 (br s, 6H, NMe2), 2.08 (br s, 2H, CH2SiMe3), 2.75 (s, 6H, NMe2), 3.46 (br s, 2H, CH(CH3)2), 3.86 (br s, 2H, CH(CH3)2), 4.17−4.18 (m, 1H, 3-NC5H5(p-NMe2)), 4.57 (d, 2JYH = 36.6 Hz, 2H, 2-NC5H5(p-NMe2)), 5.23 (dd, 3JHH = 2.4 Hz, 4JHH = 2.4 Hz, 1H, 5-NC5H5(p-NMe2)), 6.06 (d, 3JHH = 6.0 Hz, 3H, 6-NC5H5(pNMe2) and 3-, 5-NC5H4(p-NMe2)), 6.58−7.21 (m, 14H, Ph-H and Ar-H and C5H4), 7.47 (d, 3JHH = 6.6 Hz, 1H, Ar-H), 7.87 (br s, 2H, Ph-H), 9.13 ppm (br s, 2H, 2-, 6-NC5H4(p-NMe2)). 13C NMR (150 MHz, C6D6, 128.06 ppm, 25 °C): δ 0.17 (s, 3C, CH2SiMe3), 17.69 (s, 1C, CH2SiMe3), 23.62 (s, 2C, CH(CH3)2), 25.18 (s, 4C, CH(CH3)2), 26.34 (s, 2C, CH(CH3)2), 28.52 (s, 2C, CH(CH3)2), 38.04 (s, 2C, NMe2), 41.36 (s, 2C, NMe2), 47.95 (s, 2C, NCH(CH3)2), 48.73 (s, 1C, 2-NC5H5(p-NMe2)), 79.65 (s, 1C, 3-NC5H5(p-NMe2)), 90.84 (s, 1C, 5-NC5H5(p-NMe2)), 106.76 (s, 2C, 3-, 5-NC5H4(p-NMe2)), 114.64, 116.71, 119.93, 120.27 (br s, 6C, C5H4 and Ar-C), 123.45 (s, 2C, Ar-C), 130.61 (s, 4C, Ph-C), 132.13 (br s, 4C, Ph-C), 132.90 (br s, 4C, Ph-C), 143.83 (s, 2C, ipso-Ar-C), 145.27 (s, 1C, ipso-Ar-C), 147.15 (s, 1C, 6-NC5H5(p-NMe2)), 149.84 (s, 1C, 4-NC5H5(p-NMe2)), 151.24 (s, 2C, 2-, 6-NC5H4(p-NMe2)), 154.59 (s, 1C, 4-NC5H4(pNMe 2 )), 176.89 ppm (s, 1C, NC−N). Anal. Calcd for C54H77N7PSiY (%): C, 66.71; H, 7.98; N, 10.09. Found: C, 67.04; H, 8.11; N, 9.95. CCDC-866783 (2), 866784 (3), 866785 (4), 866786 (7), and 866780 (8) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/ cif. 4585
dx.doi.org/10.1021/om3003703 | Organometallics 2012, 31, 4579−4587
Organometallics
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ASSOCIATED CONTENT
S Supporting Information *
X-ray crystallographic data for 5 and crystallographic data and structure refinement details for complexes 2−4, 7, and 8. 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] (D.C.), jsu@staff.uni-marburg.de (J.S.). Fax: (+86) 431 85262774 (D.C.), +49 (0)6421 2825711 (J.S.). Tel: +86 431 85262773 (D.C.), +49 (0)6421 2825693 (J.S.). Author Contributions #
The authors contributed equally to this work.
Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was partly supported by The National Natural Science Foundation of China for project Nos. 20934006, 51073148, and 51021003 and the Ministry of Science and Technology of China for project No. 2011DFR50650. In addition, this work was also supported by Deutsche Forschungsgemeinschaft Priority Program “Lanthanoide specific functionality” Su 127/8-2. N.K.H. thanks Studienstiftung des deutschen Volkes for a fellowship.
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