Article pubs.acs.org/Organometallics
Synthesis of Rhenium Vinylidene and Carbyne Complexes from Reactions of [Re(dppm)3]I with Terminal Alkynes and Alkynols Ka Wing Chan, Wei Bai, Kui Fun Lee, Ka-Ho Lee, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin,* and Guochen Jia* Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People’s Republic of China S Supporting Information *
ABSTRACT: Treatment of [Re(dppm)3]I (dppm = PPh2CH2PPh2) with HCCPh produced the rhenium vinylidene complex ReI(CCHPh)(dppm)2. In the presence of HI, [Re(dppm)3]I reacted with HCCR (R = Ph, p-tolyl, C6H4-o-CHO, (CH2)5CH3) to give the rhenium carbyne complexes [ReI(CCH2R)(dppm)2]I and with HCCSiMe3 to give [ReI(CMe)(dppm)2]I. One-pot reactions of [Re(dppm)3]I, HCCC(OH)RR′ (RR′ = Ph2, Me2, PhMe), and HI produced the vinylcarbyne complexes [ReI(CCHCRR′)(dppm)2]I.
■
(CO)2(PR3)3]BF4 (PR3 = PPh(OEt)2, PPh2(OEt)),9 and Cp*Re(Me)(NO)(PPh3)/HBF4;10 allenylidene complexes have been isolated from the reactions of terminal alkynols with Re(OTf)(CO)2(P)3 (P3 = triphos,11 1,5,9-tris(isopropyl)1,5,9-triphosphacyclododecane 7 ) and [Re(η 2 -H 2 )(CO)2(PR3)3] BF4 (PR3 = PPh(OEt)2, PPh2(OEt)).9 The reactions of terminal alkynols with Re(OTf)(CO)2(triphos) could also give other interesting complexes, including hydroxyvinylidene, alkenylvinylidene, and dinuclear vinylidene−carbene complexes, depending on the substituents on the alkynols.12 In view of the rich chemistry of group 8 metal CO-free vinylidene, allenylidene, and related complexes, it is desirable to synthesize analogous rhenium complexes. In principle, reactions of CO-free Re(I) complexes with terminal alkynes and alkynols could also give vinylidene or allenylidene complexes. However, such reactions have been rarely reported. Under thermal (4−14 days of reflux in THF13) or photochemical (tungsten-filament bulb, 4−6 days;13 sunlight, 0.5−3 h14) conditions, the complex ReCl(N2)(dppe)2 can react with terminal alkynes HCCR (R = Ph, C6H4Me-4, Et, tBu, SiMe3, CO 2 Me, CO 2 Et, C 6 H 10-1-OH) to give the vinylidene complexes ReCl(CCHR)(dppe)2. Upon activation by TlBF4, ReCl(CNMe)(dppe)2 reacted with TlBF4/HCCPh to give [Re(CCHPh)(CNMe)(dppe)2]BF4.15,16 Reactions of terminal alkynes with carbonyl-free d6 Re(I) complexes could also give complexes other than vinylidene complexes. For example, the complex ReCl(N2)(PMe3)4 reacts with TlPF6/ HNiPr2/HCCTMS to give trans-[Re(CCSiMe3)( CMe)(PMe3)4]PF617 and ReCl(N2)(PPh3){P(OMe)3}3 reacts with PhCCH to give the acetylide complex ReCl(C CPh)(PPh3){P(O)(OMe)2}{P(OMe)3}2.15
INTRODUCTION Reactions of d6 metal complexes with terminal alkynes and alkynols have been widely explored to make interesting transition-metal complexes with a metal−carbon multiple bond, including vinylidene, allenylidene, and carbyne (when the reactions were carried out in the presence of an acid) complexes,1 especially for group 8 metals.2−5 Although potentially useful, similar chemistry has been less explored for d6 Re(I) complexes. A literature survey shows that Re(I) complexes which were reported to react with terminal alkynes or alkynols to give vinylidene or allenylidene complexes are usually those with CO or cyclopentadienyl ligands (Chart 1). For example, vinylidene complexes have been isolated from the reactions of terminal alkynes with Re(OTf)(CO)2(triphos) or [Re(H2)(CO)2(triphos)]+ (triphos = MeC(CH2PPh2)3),6 Re(OTf)(CO)(P3) (P3 = 1,5,9-tris(isopropyl)-1,5,9-triphosphacyclododecane),7 CpRe(CO)2(THF),8 [Re(η2-H2)Chart 1. Examples of Re(I) Complexes That Are Reported To React with Terminal Alkynes To Give Vinylidene or Allenylidene Complexes
Received: July 17, 2016
© XXXX American Chemical Society
A
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics In this work, we report our results derived from reactions of [Re(dppm)3]I with terminal alkynes and alkynols. In particular, we will show that (i) [Re(dppm)3]I can react with terminal alkynes to give vinylidene complexes and (ii) the one-pot reactions of [Re(dppm)3]I with terminal alkynes and alkynols in the presence of HI provide a convenient way to prepare carbyne complexes [ReI(CCH2R)(dppm)2]I and vinylcarbyne complexes [ReI(CCHCRR′)(dppm)2]I in good yields. The results are interesting, as rhenium organometallic compounds of the types ReX(CCHR)(PR′3)4 and [ReX(CR)(PR′3)4]+ are still rare.
Scheme 1. Reaction of [Re(dppm)3]I with PhCCH
■
RESULTS AND DISCUSSION Synthesis and Characterization of the Rhenium Vinylidene Complex ReI(CCHPh)(dppm)2. This work reported here stems from our effort in the development of synthetic methods for carbonyl-free d2 rhenium(V) vinylcarbyne complexes. To the best of our knowledge, rhenium vinylcarbyne complexes reported prior to our work are limited to the carbonyl-containing complexes [Re(CC(R)CPh2)(CO)2(triphos)](OTf)2 (R = H, Me)18 and [Cp*(CO)2( CCHCMe2)]BF4,19 although a number of d2 Re(V) carbyne complexes are now known.20−24 We have recently shown that the carbonyl-free d2 rhenium(V) vinylcarbyne complexes ReCl 2 {CCHC(R)C CSiMe3}(PMe2Ph)3 (R = CMe3, CHMe2, adamantyl) are useful precursors to rhenabenzyne complexes.25 To continue our interest and effort in the development of rhenabenzyne chemistry, we were prompted to develop an alternative route that can be used to easily prepare carbonyl-free d2 rhenium(V) vinylcarbyne complexes. We envisioned that reactions of carbonyl-free d6 Re(I) complexes with terminal alkynols may give hydroxyvinylidene or allenylidene complexes, which can then be protonated to give the desired carbonyl-free d2 rhenium(V) vinylcarbyne complexes. The poor activity of ReCl(N2)(dppe)2 toward alkynols (the reaction of ReCl(N2)(dppe)2 with 1-ethynyl-1-cyclohexanol takes 14 days to go completion in refluxing THF13) prompted us to search for carbonyl-free d6 Re(I) complexes that could be more reactive toward terminal alkynols. [Re(dppm)3]I (1) is an interesting complex with six phosphine−rhenium bonds.26 We suspect that, due to steric effects, one of the three dppm ligands could easily dissociate from the metal center to give the coordinatively unsaturated fragment ReI(dppm)2, which may react with terminal alkynols to give hydroxyvinylidene or allenylidene complexes; these may be further protonated to give vinylcarbyne complexes. Before this possibility was explored, we first studied the reaction of [Re(dppm)3]I with PhCCH in order to see if formation of the vinylidene complex ReI(CCHPh)(dppm)2 is easily achievable. When a mixture of [Re(dppm)3]I and PhCCH in THF was heated at 60 °C for 6 h, the rhenium vinylidene complex ReI(CCHPh)(dppm)2 (2) was produced, which can be isolated as an orange solid in 74% yield (Scheme 1). As monitored by in situ NMR, the reaction also produced a minor product with a 31P NMR signal assignable to the carbyne species [ReI(CCH2Ph)(dppm)2]+ (see below), which might be formed by protonation with a trace amount of water present in the reaction medium. The formation of the carbyne side product can be eliminated by the addition of bases such as K2CO3 in the reaction mixture.
Complex 2 has been characterized by NMR and elemental analysis. In particular, the 31P{1H} NMR spectrum showed a singlet peak at −38.7 ppm. In the 13C{1H} NMR spectrum, the ReC signal was found at 300.0 ppm and that of CHPh at 108.4 ppm. The 1H NMR spectrum showed a characteristic high-field resonance of ReCCHPh at 0.30 ppm. The NMR data associated with the vinylidene ligand are similar to those of ReCl(CCHC6H4-4-Me)(dppe)2, which showed the 1H signal of ReCCHAr at 0.72 ppm and 13C signals of ReC and ReCCHAr at 295.30 and 108.46 ppm, repectively.14 The unusually upfield shift of the vinylidene 1H signal may be partially caused by the effect of the phenyl rings of the dppm or dppe ligand. The structure of 2 has been confirmed by X-ray diffraction. As shown in Figure 1, the complex has an octahedral geometry with the iodide being trans to the vinylidene ligand. The Re− C−C group is not perfectly linear and has an angle of 172.93(12)°. The ReC bond length (1.863(4) Å) is at the low end of those (1.840−2.046 Å) observed for structurally characterized rhenium vinylidene complexes ([Re{CC(H)Ph}(CO)2(triphos)]BF4 (1.925(6) Å),6 ReCl{CCH-
Figure 1. Crystal structure of ReI(CCHPh)(dppm)2 (2). The hydrogen atoms of phenyl rings are omitted for clarity. Selected bond lengths (Å) and angles (deg): Re(1)−C(1) 1.863(4), Re(1)−I(1) 2.8643(3), Re(1)−P(1) 2.3986(10), Re(1)−P(2) 2.3778(11), C(1)− C(2) 1.298(6), C(2)−C(3) 1.471(6); C(1)−Re(1)−I(1) 172.93(12), C(1)−Re(1)−P(1) 88.16(12), C(2)−C(1)−Re(1) 171.6(3), C(1)− C(2)−C(3) 135.3(4). B
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics (Ph)}(dppe)2 (2.046(8) Å),13 [Cp(NO)Re{CCH(1C10H7)}(PPh3)]BPh4 (1.840(17) Å),27 Cp(CO)2ReC CHPh (1.892(14) Å),8 [Cp(CO) 2 Re(CCPhCPh CH 2 )][(CO) 2 ReCp] (1.90(3) Å), 28 [Re(CCH 2 )(NO) 2 (PiPr 3 ) 2 ]BAr 4 F (1.902(6) Å), 29 [(Me 3 SiCC)(PMe 3 ) 4 ReCCHCHCRe(CCSiMe 3 )(PMe 3 ) 4 ] (1.904(2) Å)17). The C(1)−C(2) bond distance (1.298(6) Å) is normal in comparison with those (1.289−1.387 Å) of reported structurally characterized vinylidene complexes. The chemistry of rhenium vinylidene complexes has attracted much attention. Most of the reported rhenium vinylidene complexes contain CO, NO, or Cp ligands.6−10,12,19,27−30 Complex 2 is therefore interesting, as reported examples of rhenium complexes without CO, NO, or Cp ligands are rather limited. They include ReCl(CCHR)(dppe)2 (R = Ph, C6H4Me-4, Et, tBu, SiMe3, CO2Me, CO2Et, C6H10-1-OH),13,14 Re(CN)(CCHPh)(dppe)2,16 (Me3SiCC)(PMe3)4Re CCHCHCRe(CCSiMe3)(PMe3)4,17 and [Re( CCHPh)(CNMe)(dppe)2]BF4.15 The iodide anion in the precursor complex [Re(dppm)3]I appears to be essential for the formation of vinylidene complexes, as no reaction was observed when [Re(dppm)3]BPh4 (1BPh4) was treated with PhCCH under similar conditions. We believe that iodide anion could assist the dissociation of one dppm ligand to give the active species ReI(dppm)2 (A), which reacts with PhCCH to give the vinylidene complex 2 via the η2-alkyne complex ReI(η2-HC CPh)(dppm)2 (B) (Scheme 1), although we failed to detect the intermediate species A and B. Our computational study indicates that the dissociation of H2PCH2PH2 from [Re(PH2CH2PH2)3]I (3, a model for 1) to give the intermediate ReI(PH2CH2PH2)2 (4, a model for A) is thermodynamically unfavored by 26.74 kcal/mol (Scheme 2).
ReCl(H2PCH2CH2PH2)2 (7, a model for ReCl(dppe)2) with PhCCH to give the vinylidene complex 8 was found to be similar to that for the reaction of 4 with PhCCH to give the vinylidene complex 5. However, the dissociation of N2 from ReCl(N2)(H2PCH2CH2PH2)2 (6) to give the 16e species ReCl(H2PCH2CH2PH2)2 (7) was found to be thermodynamically much more unfavorable than the dissociation of H2PCH2PH2 from [Re(PH2CH2PH2)3]I (3) to give 4 (by 35.41 and 26.74 kcal/mol, respectively). It is noted that the reactions of ReCl(N2)(dppe)2 with HC CR to give vinylidene complexes trans-ReCl{CCHR}(dppe)2 under thermal conditions usually proceed slowly (4− 14 days of reflux in THF).13 In contrast, the reaction of [Re(dppm)3]I with PhCCH to give vinylidene complex 2 in refluxing THF is completed within 6 h. The computational results suggest that the difference in the reactivities of ReCl(N2)(dppe)2 and [Re(dppm)3]I toward PhCCH can be related to the relative ease of formation of coordinatively unsaturated 16e species. It is noted that the iodide and vinylidene ligands in 2 are trans to each other. In principle, the complex could also adopt an isomer in which the iodide and vinylidene ligands are cis to each other. However, we have no evidence for the formation of the cis isomer. In agreement with the experimental observation, our computational study indicates that the trans isomer transReI(CCHPh)(PH2CH2PH2)2 (5) is thermodynamically more stable by 8.27 kcal/mol than the cis isomer cis- ReI( CCHPh)(PH2CH2PH2)2 (5cis). Synthesis and Characterization of Cationic Rhenium Carbyne Complexes. The experiments described above clearly show that [Re(dppm)3]I (1) can react with HC CPh to give the vinylidene complex [ReI(CCHPh)(dppm)2] (2). Further experiments revealed that protonation of 2 with HI readily produced the carbyne complex [ReI( CCH2Ph)(dppm)2]I (9a) and treatment of 9a with K2CO3 gave 2 (eq 1).
Scheme 2. Free Energy Changes for the Reactions of PhC CH with the Model Complexes ReCl(N2)(PH2CH2CH2PH2)2 and [Re(PH2CH2PH2)3]I Calculated at the B3LYP Level
We next explored the possibility of synthesizing cationic rhenium carbyne complexes through one-pot reactions of [Re(dppm)3]I (1) with terminal alkynes in the presence of hydriodic acid. When a mixture of [Re(dppm)3]I and PhC CH in THF was heated in the presence of 1.5 equiv of HI at 60 °C for 6 h, the rhenium carbyne complex [ReI(CCH2Ph)(dppm)2]I (9a) was produced as the only rhenium-containing product, which can be isolated as an orange solid in 73% yield (Scheme 3). Under similar reaction conditions, arylacetylenes such as HCCC6H4-p-Me and HCCC6H4-o-CHO reacted with [Re(dppm)3]I (1) to give the carbyne complexes 9b,c, respectively (Scheme 3). The alkylacetylene HCC(CH2)4Me also reacted with 1 to give an analogous carbyne complex which was isolated as the BPh4 salt 9d. The identity of the new carbyne complexes (9a−d) can be readily assigned on the basis of their NMR data. The 31P{1H} NMR spectra showed a singlet around 44 ppm. The 13C{1H}
Subsequent reaction of 4 with PhCCH to give ReI(C CHPh)(PH2CH2PH2)2 (5, a model for 2) is thermodynamically favored by 54.89 kcal/mol. Overall, the reaction is thermodynamically favored by 28.15 kcal/mol, in agreement with the experimental observation that complex 2 can be produced from the reaction of 1 with PhCCH. For comparison, we have also calculated the free energy change for the reaction of ReCl(N2)(H2PCH2CH2PH2)2 (6, a model for ReCl(N2)(dppe)2) with PhCCH to give the vinylidene complex ReCl(CCHPh)(H2PCH2CH2PH2)2 (8, a model for ReCl(CCHPh)(dppe)2). Overall, the reaction is thermodynamically favored by 18.07 kcal/mol. The free energy change for the reaction of the intermediate C
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics Scheme 3. Synthesis of Cationic Rhenium Carbyne Complexes
a
Figure 2. Crystal structure of the complex [ReI(CMe)(dppm)2]I (9e). The iodide counteranion and the hydrogen atoms of the dppm ligands are omitted for clarity. Selected bond lengths (Å) and angles (deg): Re(1)−I(1) 2.8306(3), Re(1)−P(1) 2.4237(9), Re(1)−P(2) 2.4365(8), Re(1)−P(3) 2.4591(8), Re(1)−P(4) 2.4665(8), Re(1)− C(1) 1.765(4), C(1)−C(2) 1.448(5); P(1)−Re(1)−I(1) 85.29(2), P(1)−Re(1)−P(2) 69.28(3), P(1)−Re(1)−P(3) 170.50(3), C(1)− Re(1)−I(1) 173.60(11), C(2)−C(1)−Re(1) 174.8(3).
The reactions were carried out in refluxing THF for 6 h.
NMR spectra showed a characteristic carbyne signal at 268− 277 ppm and the CCH2R signal at 48−54 ppm. In the 1H NMR spectrum, the CCH2Ar signal was observed at 1.5−2.2 ppm and the CCH2(CH2)5CH3 signal at −0.07 ppm. When Me3SiCCH was used, the reaction produced the carbyne complex [ReI(CMe)(dppm)2]I (9e) due to hydrolysis of the TMS group. Hydrolysis of TMS group(s) has been observed preciously in the reactions of TMSsubstituted alkynes with rhenium complexes: for example, in the reaction of ReCl(N2)(PMe3)4 with TlPF6/HNiPr2/HC CTMS to give trans-[Re(CCSiMe3)(CMe)(PMe3)4]PF617 and in the reaction of [Re(H2)(CO)2(triphos)]BF4 with HC CTMS to give a mixture of [Re{CC(H)TMS}(CO)2(triphos)]BF4 and [Re(CCH2)(CO)2(triphos)]BF4.6a The structure of complex 9e has been confirmed by X-ray diffraction (Figure 2). In the complex, the ReC bond length is 1.765(4) Å, which is in the range of the reported values (1.67−1.82 Å) of ReC bonds.31 The solution NMR data are in agreement with the solid-state structure. In particular, the 31 1 P{ H} NMR spectrum (in CD2Cl2) showed a singlet at −44.1 ppm. The 13C{1H} NMR spectrum showed the ReC signal at 273.5 ppm and the CCH3 signal at 32.5 ppm. Interestingly, the proton signal of ReCCH3 appears at −0.45 ppm, which is unusually upfield for a typical organic methyl group. An unusual upfield chemical shift of ReCMe has also been reported previously. For example, the 1H signal of ReCMe appears at 0.45 ppm for [ReCl(CMe)(dppe)2]BF4,14 1.27 ppm for [Re(CCSiMe3)(CMe)(PMe3)4]PF6, and 1.14 ppm for {iPr2PCH2SiMe2)2N}HReCMe.21b The phenyl rings of the dppm ligand in 9e may also influence the 1 H chemical shift of ReCMe. Reactions of [Re(dppm)3]I with Terminal Alkynols. The successful isolation of carbyne complexes 9 from the onepot reactions of [Re(dppm)3]I with terminal alkynes and HI hinted that it may be possible to make vinylcarbyne complexes using alkynols. To test this possibility, we first studied the reaction with HCCC(OH)Ph2. When a mixture of [Re(dppm)3]I and HCCC(OH)Ph2 in THF was heated in the presence of 1.5 equiv of HI at 60 °C for
6 h, we were pleased to find that the rhenium carbyne complex [Re(CCHCPh2)I(dppm)2]I (10a) was produced as a dark red solid, which can be isolated as an orange solid in 67% yield (Scheme 4). Under similar conditions the reaction with HC Scheme 4. Reactions of [Re(dppm)3]I with Alkynols in the Presence of HI
a
The reactions were carried out in refluxing THF for 6 h.
CC(OH)Me2 produced the analogous carbyne complex 10b. When HCCC(OH)PhMe was used, the reaction produced the vinylcarbyne complex 10c as a mixture of E (10c(E)) and Z (10c(Z)) isomers in a molar ratio of 3.4:1. The structure of the carbyne complex 10a has been confirmed by X-ray diffraction (Figure 3). The ReC bond length is 1.781(4) Å, which is similar to that (1.765(4) Å) of the rhenium carbyne 9e. Consistent with the solid-state D
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics
Scheme 5. Reaction of HCCC(OH)Ph2 with [Re(dppm)3] I in the Absence of HI
Figure 3. Crystal structure of complex [ReI(CCHCPh2)(dppm)2]I (10a). The iodide counteranion and the hydrogen atoms of phenyl rings are omitted for clarity. Selected bond lengths (Å) and angles (deg): Re(1)−I(1) 2.8258(3), Re(1)−P(1) 2.4753(9), Re(1)− P(2) 2.4464(9), Re(1)−P(3) 2.4345(9), Re(1)−P(4) 2.4482(9), Re(1)−C(1) 1.781(4), C(1)−C(2) 1.430(5), C(2)−C(3) 1.351(5), C(3)−C(4) 1.487(5), C(3)−C(11) 1.478(5); C(1)−Re(1)−I(1) 172.76(12), C(10)−P(1)−Re(1) 95.42(12), C(1)−Re(1)−P(1) 100.66(12), C(2)−C(1)−Re(1) 165.2(3), C(3)−C(2)−C(1) 130.0(4).
structure, the 1H NMR spectrum showed a characteristic Re CCH signal at 4.33 ppm. The 13C{1H} NMR spectrum showed signals at 256.7 (ReC), 150.8 (ReCCH), and 125.2 (Re CCHCPh2) ppm. The 31P{1H} NMR spectrum showed a singlet at −43.5 ppm. The identity of other new carbyne complexes (10b,c) can be readily assigned on the basis of their NMR data. Considering that [Re(dppm)3]I can react with PhCCH to give the rhenium vinylidene complex ReI(CCHPh)(dppm)2, it is reasonable to assume that the one-pot reactions of alkynols HCCC(OH)R2 with [Re(dppm)3]I proceed by initial formation of hydroxyvinylidene intermediates ReI{ CCHC(OH)R2}(dppm)2, followed by electrophilic abstraction of the OH group of the hydroxyvinylidene intermediates. In supporting the proposed reaction sequence, the reaction of HCCC(OH)Ph2 with [Re(dppm)3]I in the absence of HI produced the hydroxycarbyne complex ReI{CCHC(OH)Ph2}(dppm)2 (11) as the major product along with minor unidentified products. As expected, protonation of 11 with HI produced the carbyne complex 10a (Scheme 5). The structure of 11 has also been confirmed by X-ray diffraction (Figure 4). The complex has a coordination sphere similar to that of complex 2. The solid structure is fully consistent with the solution NMR data. The 31P{1H} NMR spectrum showed a singlet peak at −39.8 ppm. The 13C{1H} NMR spectrum displayed the ReC signal at 294.6 ppm, the CH signal at 116.6 ppm, and the C(OH) signal at 69.7 ppm. The 1H NMR spectrum showed a characteristic high-field resonance of ReCCH at 0.40 ppm. In principle, the protonation reaction of 11 could also produce the hydroxycarbyne complex [ReI{CCH2C(OH)Ph2}(dppm)2]I (12; Scheme 5). However, we have no evidence for such a product. To understand the selectivity, we have calculated the energy profiles for the protonation of the
Figure 4. Crystal structure of ReI{CCHC(OH)Ph2}(dppm)2 (11). The hydrogen atoms of phenyl rings are omitted for clarity. Selected bond lengths (Å) and angles (deg): Re(1)−I(1) 2.8555(3), Re(1)−C(1) 1.892(5), C(1)−C(2) 1.309(7), C(2)−C(3) 1.503(7), Re(1)−P(1) 2.4035(11), Re(1)−P(2) 2.4156(11), Re(1)−P(3) 2.4047(11), Re(1)−P(4) 2.4103(10), O(1)−C(3) 1.450(6); P(1)− Re(1)−I(1) 83.46(3), P(1)−Re(1)−P(2) 69.59(4), C(1)−Re(1)− I(1) 173.89(13), C(1)−Re(1)−P(1) 91.55(14), C(2)−C(1)−Re(1) 172.1(4), C(1)−C(2)−C(3) 130.7(5), O(1)−C(3)−C(2) 109.2(4), C(2)−C(3)−C(21).
complex 13 (a model for 11) to give the vinylcarbyne complex 14 (a model for 10a) and the hydroxycarbyne complex 15 (a model for 12) (Scheme 6). Our computational studies suggest that the outcome is of both thermodynamic and kinetic origin. As shown in Scheme 6, the formation of the vinylcarbyne complex 14 and the hydroxycarbyne complex 15 from the protonation of the model carbyne complex 13 is thermodynamically favored by 25.44 and 19.43 kcal/mol, respectively. The barrier for formation of 14 (3.98 kcal/mol) is lower than that (6.05 kcal/mol) for the formation of 15. The one-pot reactions of 1 with alkynes and alkynols to give carbyne complexes [ReI(CCH2R)(dppm)2]I (9) and vinylcarbyne complexes [ReI(CCHCRR′)(dppm)2]I (10) are E
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Organometallics
■
Scheme 6. Free Energy Changes for the Protonation of the Model Complex 13 Calculated at the B3LYP Level
Article
EXPERIMENTAL SECTION
All manipulations were carried out under a nitrogen atmosphere using standard Schlenk techniques unless otherwise stated. Solvents were distilled under nitrogen from sodium benzophenone (THF, ether, nhexane), or calcium hydride (CH2Cl2). The starting material [Re(dppm)3]I was prepared following the procedure described in the literature.26 All other reagents were used as purchased from Aldrich Chemical Co. Microanalyses were performed by M-H-W Laboratories (Phoenix, AZ). 1H, 13C{1H}, and 31P{1H} spectra were collected on a Bruker ARX-400 spectrometer (400 MHz), a JEOL EX400 spectrometer (400 MHz), or a Bruker ARX-300 spectrometer (300 MHz). 1H and 13C NMR shifts are relative to TMS, and 31P chemical shifts are relative to 85% H3PO4. ReI(CCHPh)(dppm)2 (2). Method A. A mixture of [Re(dppm)3]I (1; 0.500 g, 0.340 mmol) and phenylacetylene (0.19 mL, 0.18 g, 1.7 mmol) in THF (15 mL) was refluxed for 6 h. The reaction mixture was then cooled to room temperature. The volatiles were removed under vacuum to give an orange residue. The residue was washed with diethyl ether (10 mL × 3). The orange solid was dried under vacuum. Yield: 0.33 g, 74%. Method B. [ReI(CCH2Ph)(dppm)2]I (9a; 0.089 g, 0.068 mmol) and K2CO3 (0.0190 g, 0.137 mmol) were placed in a 50 mL Schlenk round-bottom flask. MeOH (10 mL) was placed in the flask. The reaction mixture was stirred at room temperature for 1 h. The solvent was evaporated under vacuum. The residue was extracted with benzene. The extract was filtrated through a filter paper. The solvent of the filtrate was removed under vacuum. The solid that was collected was dried under vacuum. Yield: 0.075 g, 93%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −38.7 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.55− 7.13 (m, 40H, PPh2), 6.56 (t, 3JHH = 7.6 Hz, 2H, Ph), 6.45 (t, 3JHH = 7.6 Hz, 1H, Ph), 6.16−6.12 (m, 2H, CH2-dppm), 6.01−5.96 (m, 2H, CH2-dppm), 5.58 (d, 3JHH = 7.2 Hz, 2H, Ph), 0.30 (quintet, 4JPH = 6.0 Hz, 1H, CCH). 13C{1H} NMR (101 MHz, CD2Cl2): δ 300.0 (quintet, 2JPC = 11.1 Hz, ReC), 137.0−119.7 (multiple 13C signals of Ph of dppm and the vinylidene ligands), 108.4 (CCH), 60.3 (br s, CH2-dppm). Anal. Calcd for C58H50IP4Re: C, 58.83; H, 4.26. Found: C, 59.21; H, 4.51. [Re(dppm)3]BPh4 (1BPh4). [Re(dppm)3]I (1; 0.500 g, 0.341 mmol) was dissolved in dichloromethane (5 mL) in a 50 mL roundbottom flask. NaBPh4 (0.128 g, 0.374 mmol) in MeOH (5 mL) was placed in the flask. The reaction mixture was stirred at room temperature for 45 min to give a yellow precipitate. The reaction mixture was then filtered through a filter paper, and the residue was washed with MeOH (5 mL × 2) to give a pale yellow solid which was dried under vacuum. Yield: 0.315 g, 80.0%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −51.0 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.35−7.24 (m, 39H, Ph), 7.12−7.03 (m, 14H, Ph), 6.91 (t, 3JHH = 7.2 Hz, 4H, Ph), 6.78 (t, 3JHH = 7.6 Hz, 12H, Ph), 6.64−6.62 (br d, 3JHH = 6.4 Hz, 11 H, Ph), 5.52 (br s, 6H, CH2-dppm). 13C{1H} NMR (101 MHz, CD2Cl2): δ 164.2−162.7 (m, BPh4), 143.2 (br m, BPh4), 136.7 (br m, BPh4), 135.3 (s, Ph), 131.1 (s, Ph), 130.4 (s, Ph), 129.2 (s, Ph), 128.3 (s, Ph), 127.7 (s, Ph), 127.5 (s, Ph), 125.0−124.9 (m, BPh4), 121.0 (s, Ph), 56.25 (br s, CH2-dppm). Anal. Calcd for C99H86BP6Re·H2O: C, 70.96; H, 5.23. Found: C, 70.60; H, 5.58. [ReI(CCH2Ph)(dppm)2]I (9a). [Re(dppm)3]I (1; 0.490 g, 0.334 mmol) was placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by phenylacetylene (0.190 mL, 0.176 g, 1.73 mmol). Then, aqueous hydroiodic acid (47%, 0.090 mL, 0.51 mmol) was added. The reaction mixture was refluxed for 6 h to give an orange-brown solution. The reaction mixture was cooled to room temperature and then filtered through a filter paper. The solvent of the filtrate was removed under vacuum. The residue was washed with diethyl ether (15 mL × 3). The solid was then dried under vacuum. Yield: 0.32 g, 73%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −44.5 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.67−7.29 (m, 40H, PPh2), 7.00 (t, 3JHH = 7.5 Hz, 1H, Ph), 6.77 (t, 3 JHH = 7.6 Hz, 2H, Ph), 6.37−6.31 (m, 2H, CH2-dppm), 5.97−5.92 (m, 2H, CH2-dppm), 5.63 (d, 3JHH = 7.6 Hz, 2H, Ph), 1.46 (quintet, 4 JPH = 3.2 Hz, 2H, CCH2). 13C{1H} NMR (101 MHz, CD2Cl2): δ
interesting, as they provide a convenient way to obtain carbonyl-free rhenium(V) carbyne complexes, which are potentially useful in materials chemistry and organometallic synthesis. Although many d2 Re(V) carbyne complexes containing one or more carbonyl ligands have been reported,18−20,24 d2 Re(V) carbyne complexes without a CO ligand are less known. The complexes {R′2PCH2SiMe2)2N}HReCR (R′ = Cy, iPr) were prepared from the reactions of {R′2PCH2SiMe2)2N}ReH4 with alkenes or alkanes.21 The complex (mq)(PPh3)2HReCCH2R (mq = the anion of 2mercaptoquinoline) was produced by deprotonation of [(mq)(PPh3) 2H2ReCCH2R]PF 6.22 The complexes ReCl2( CCH2R)(PMe2Ph)3 and ReCl2(CCHCRR′)(PMe2Ph)3 were obtained in low yields from the reactions of ReH5(PMe2Ph)3 with HCCR and HCCC(OH)RR′ in the presence of HCl.25,32 The complex [Cp*Re(CCMe3)(PMe3)2]Cl was prepared by the reaction of Cp*ReCl2( CCMe3) with excess PMe3.23 Complexes 9 and 10 represent rare examples of Re(V) carbyne complexes of the type [ReX(CR)(PR′3 ) 4]+. Reported Re(V) carbyne complexes of this type are limited to [ReX(CCH2R)(dppe)2]+ (X = Cl, F) prepared by protonation of the vinylidene complexes ReCl(CCHR)(dppe)2 or one-pot photochemical reactions of ReCl(N2)(dppe)2 with HCCR/NH4BF4,33 [ReCl(CC6H2Me3)(pdpp)2]ClO4 (pdpp = o-phenylenebis(o-diphenylphosphine) prepared by the reaction of [ReCl(CC6H2Me3)(CO)4]ClO4 with pdpp,20a and trans-[Re(CCSiMe3)(CMe)(PMe3)4]+ prepared by the reactions of ReCl(N2)(PMe3)4 with TlPF6/ HNiPr2/HCCTMS.17 These complexes are interesting, as they can display interesting redox and photophysical properties. We noted that the related tungsten carbyne complexes WX( CR)(diphosphine)2 have attracted considerable attention for their photophysical and material properties.34 Conclusion. We have demonstrated that the complex [Re(dppm)3]I can be used as a source of the 16e metal fragment ReI(dppm)2. It can react with terminal alkynes HC CR to give vinylidene complexes trans-ReI(CCHR)(dppm)2. One-pot reactions of [Re(dppm)3]I with terminal alkynes and alkynols in the presence of HI provide a convenient way to prepare carbyne complexes [ReI(CCH2R)(dppm)2]I as well as vinylcarbyne complexes [ReI(CCHCRR′)(dppm)2]I in good yields. The vinylidene and carbyne complexes are potentially useful starting materials for the synthesis of other interesting rhenium organometallic compounds through manipulation of the vinylidene or carbyne group, dppm (e.g., change it to hemilabile Ph2PCH2P(O)Ph2), and halide ligands. Exploration of the chemistry developed here for organometallic synthesis is in progress in our laboratory. F
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics 268.4 (quintet, 2JPC = 13.0 Hz, ReC), 134.2−126.5 (multiple 13C signals of Ph of dppm and the carbyne ligands), 59.1−58.5 (m, CH2dppm), 53.3 (s, CCH2). Anal. Calcd for C58H51I2P4Re·H2O: C, 52.38; H, 4.01. Found: C, 52.57; H, 4.49. [ReI(CCH2-p-tolyl)(dppm)2]I (9b). [Re(dppm)3]I (1; 0.505 g, 0.344 mmol) was placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by 4-ethynyltoluene (0.220 mL, 0.202 g, 1.73 mmol). Then, hydroiodic acid (47%, 0.090 mL, 0.51 mmol) was added. The reaction mixture was refluxed for 6 h to give a brown solution with an orange precipitate. The reaction mixture was cooled to room temperature and then filtered through a filter paper to remove the orange solid. The filtrate was dried under vacuum. The residue was washed with diethyl ether (15 mL × 3) followed by methanol (7 mL × 2) and last acetone (6 mL). The solid was then dried under vacuum. Yield: 0.33 g, 72%. 31 1 P{ H} NMR (162 MHz, CD2Cl2): δ −44.1 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.67−7.30 (m, 40H, PPh2), 6.54 (d, 3JHH = 7.6 Hz, 2H, −C6H4−), 6.3−6.4 (m, 2H, CH2-dppm), 5.9−6.0 (m, 2H, CH2dppm), 5.54 (d, 3JHH = 8.0 Hz, 2H, C6H4), 2.19 (s, 3H, C6H4CH3), 1.46 (quintet, 4JPH = 3.2 Hz, 2H, CCH2). 13C{1H} NMR (101 MHz, CD2Cl2): δ 269.0 (quintet, 2JPC = 12.5 Hz, ReC), 136.1− 124.1 (multiple 13C signals of Ph of dppm and the carbyne ligands), 59.2−58.6 (m, CH2-dppm), 52.6 (s, CCH2), 20.1 (s, C6H4CH3). Anal. Calcd for C59H53I2P4Re: C, 53.44; H, 4.03. Found: C, 53.22; H, 4.15. [ReI(CCH2C6H4-o-CHO)(dppm)2]I (9c). [Re(dppm)3]I (1; 0.400 g, 0.272 mmol) and o-ethynylbenzaldehyde (0.178 g, 1.37 mmol) were placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by hydroiodic acid (57%, 0.060 mL, 0.41 mmol). The reaction mixture was refluxed for 6 h and cooled to room temperature and then dried under vacuum. The residue was washed with diethyl ether (15 mL × 2), followed by benzene (6 mL × 2) and finally methanol (6 mL × 2). The yellow solid was dried under vacuum. Yield: 0.23 g, 62%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −44.0 (s). 1H NMR (400 MHz, CD2Cl2): δ 8.97 (s, 1H, CHO), 7.69−7.27 (m, 42H, PPh2 and CH2dppm), 7.20−7.16 (m, 2H, CH2-dppm), 6.35 (br s, 4H, C6H4), 5.89 (br d, 3JHH = 7.5 Hz, 1H, CH2-dppm), 2.19 (br s, 2H, CCH2). 13 C{1H} NMR (101 MHz, CD2Cl2): δ 269.0 (t, 2JPC = 13.1 Hz, Re C), 191.7 (s, CHO), 135.1−127.3 (multiple 13C signals of Ph of dppm and the carbyne ligands), 58.6−58.0 (m, CH2-dppm), 50.6 (s, CCH2). Anal. Calcd for C59H51I2OP4Re: C, 52.54; H, 3.72. Found: C, 52.66; H, 3.90. [ReI(CC6H13)(dppm)2]BPh4 (9d). [Re(dppm)3]I (1; 0.471 g, 0.321 mmol) was placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by 1-heptyne (0.210 mL, 0.154 g, 1.60 mmol). Then, hydroiodic acid (47%, 0.090 mL, 0.51 mmol) was added. The reaction mixture was refluxed for 6 h. The reaction mixture was cooled to room temperature and then filtered through a filter paper. The filtrate was dried under vacuum and washed with diethyl ether (15 mL × 3). The solid residue was redissolved in methanol (8 mL). Then, sodium tetraphenylborate (0.101 g, 0.321 mmol) in methanol was placed in the product mixture to give a precipitate. The solution was removed through a filter paper, and the solid was dried under vacuum. Yield: 0.34 g, 70%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −45.0 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.63 (br s, 8H, Ph), 7.54−7.34 (m, 40H, Ph), 7.03 (t, J = 7.4 Hz, 8H), 6.88 (t, J = 7.2 Hz, 4H), 6.49 (br d, J = 15.9 Hz, 2H, CH2-dppm), 5.91−5.74 (m, 2H, CH2-dppm), 1.03−0.91 (m, 2H, CH2CH2CH3), 0.81 (t, J = 7.2 Hz, 3H, CH3), 0.69−0.54 (m, 2H, CH2CH2CH3), 0.41−0.26 (m, 2H, CH2(CH2)2CH3), −0.07 (dd, J = 6.1, 3.0 Hz, 2H, CCH2), −0.19 (dt, J = 15.6, 7.8 Hz, 2H, CH2(CH2)3CH3). 13C{1H} NMR (101 MHz, CD2Cl2): δ 278.2 (quintet, 2JPC = 12.1 Hz, ReC), 165.3−163.9 (m, BPh4), 136.5− 122.3 (multiple 13C signals of Ph of dppm and BPh4), 58.2−57.7 (m, CH2-dppm), 48.9 (s, CCH2), 31.2, 29.2, 22.6, 21.2 (all s, CH2), 14.2 (s, CH3). Anal. Calcd for C81H77BIP4Re·0.4NaI: C, 62.43; H, 4.98. Found: C, 62.71; H, 4.97. [ReI(CMe)(dppm)2]I (9e). [Re(dppm)3]I (1; 0.498 g, 0.340 mmol) was placed in a 50 mL Schlenk round-bottom flask connected
to a reflux condenser. THF (15 mL) was added, followed by trimethylsilylacetylene (0.24 mL, 1.69 mmol). Then, hydroiodic acid (47%, 0.090 mL, 0.51 mmol) was added. The reaction mixture was refluxed for 6 h to give a pale yellow suspension. The reaction mixture was cooled to room temperature. The liquid was removed by filtration through a filter paper. The pale yellow solid collected was washed with diethyl ether (15 mL × 3) and then dried under vacuum. Yield: 0.28 g, 65%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −44.1 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.59−7.26 (m, 40H, PPh2), 6.85 (br d, 2JHH = 15.9 Hz, 2H, CH2-dppm), 5.79−5.72 (m, 2H, CH2-dppm), −0.45 (quintet, 4 JPH = 3.6 Hz, 3H, CCH3). 13C{1H} NMR (101 MHz, CD2Cl2): δ 273.5 (quintet, 3JPC = 12.7 Hz, ReC), 134.0−127.6 (multiple 13C signals of Ph of dppm), 57.0−56.5 (m, CH2-dppm), 32.5 (s, CH3). Anal. Calcd for C52H47I2P4Re: C, 50.54; H, 3.83. Found: C, 50.36; H, 4.09. [ReI(CCHCPh2)(dppm)2]I (10a). [Re(dppm)3]I (1; 0.426 g, 0.290 mmol) and 1,1-diphenyl-2-propyn-1-ol (0.303 g, 1.45 mmol) were placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by hydroiodic acid (47%, 0.08 mL, 0.450 mmol). The reaction mixture was refluxed for 6 h to give a dark red solution with a red precipitate. The reaction mixture was cooled to room temperature and then filtered through a filter paper to give a red solid. The red solid was washed with diethyl ether (15 mL × 3) and dried under vacuum. Yield: 0.27 g, 67%. 31 1 P{ H} NMR (162 MHz, CD2Cl2): δ −43.5 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.76 (br s, 8H, PPh2), 7.51- 7.24 (m, 33H, PPh2), 7.13 (t, 3 JHH = 7.7 Hz, 2H, Ph), 7.05 (t, 3JHH = 7.7 Hz, 1H, Ph), 6.64−6.60 (m, 2H, Ph), 6.47−6.41 (m, 2H, CH2-dppm), 6.37 (d, 3JHH = 7.9 Hz, 2H, Ph), 5.91 (d, 3JHH = 7.6 Hz, 2H, Ph), 5.57−5.52 (m, 2H, CH2-dppm), 4.33 (quintet, 4JPH = 3.2 Hz, 1H, CHCPh2). 13C{1H} NMR (101 MHz, CD2Cl2): δ 256.7 (quintet, 2JPC = 12.5 Hz, ReC), 150.8 (s, CCH), 140.0−126.7 (multiple 13C signals of Ph of dppm and the carbyne ligands), 125.2 (s, CHCPh2), 59.5−58.9 (m, CH2-dppm). Anal. Calcd for C65H55I2P4Re: C, 55.76; H, 3.96. Found: 55.51; H, 4.11. [ReI(CCHCMe2)(dppm)2]I (10b). [Re(dppm)3]I (1; 0.500 g, 0.341 mmol) was placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by 2-methylbut-3-yn-2-ol (0.100 mL, 1.69 mmol). Then, hydroiodic acid (57%, 0.080 mL, 0.55 mmol) was added. The reaction mixture was refluxed for 6 h and cooled to room temperature and then dried under vacuum. The residue was washed with diethyl ether (15 mL × 2), followed by benzene (6 mL × 2) and finally acetone (6 mL). The yellow solid was dried under vacuum. Yield: 0.29 g, 67%. 31P{1H} NMR (162 MHz, CD2Cl2): δ −45.2 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.76 (br s, 8H, PPh2), 7.48−7.25 (m, 32H, PPh2), 6.66 (br d, 2JHH = 15.2 Hz, 2H, CH2-dppm), 6.16−5.95 (br m, 2H, CH2dppm), 3.06 (s, 1H, CHCMe2), 0.79 (s, 3H, CMe2), 0.00 (s, 3H, CMe2). 13C{1H} NMR (101 MHz, CD2Cl2): δ 263.2 (quintet, 2JPC = 11.6 Hz, ReC), 155.8 (s, CCH), 134.4−127.5 (multiple 13C signals of Ph of dppm), 132.7 (CHCMe2), 58.8−58.2 (m, CH2dppm), 25.9 (s, CMe2), 21.3 (s, CMe2), 21.1 (s, CMe2). Anal. Calcd for C55H51I2P4Re: C, 51.77; H, 4.03. Found: C, 51.73; H, 4.11. [ReI(CCHCPhMe)(dppm)2]I (10c). [Re(dppm)3]I (1; 0.500 g, 0.341 mmol) and 2-phenylbut-3-yn-2-ol (0.249 g, 1.70 mmol) were placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (15 mL) was added, followed by hydroiodic acid (57%, 0.07 mL, 0.477 mmol). The reaction mixture was refluxed for 6 h and cooled to room temperature and then dried under vacuum. The residue was washed with diethyl ether (15 mL × 3), followed by methanol (6 mL × 2). The orange-red solid was dried under vacuum. Yield: 0.317 g, 69.5%. The isolated solid contains two isomers (10c(E) and 10c(Z)) in a molar ratio of 3.38:1. Anal. Calcd for C60H53I2P4Re: C, 53.86; H, 3.99. Found: C, 53.77; H, 4.04. Characteristic spectroscopic data of the major E isomer are as follows. 31P{1H} NMR (162 MHz, CD2Cl2): δ −45.9 (s). 1H NMR (400 MHz, CD2Cl2): δ 7.81−7.18 (m, 43H, Ph, overlapped with those of the minor isomer), 6.70 (br d, 2JHH = 16.0 Hz, 2H, CH2-dppm), 6.63 (br, 2H, Ph), 6.10−6.06 (m, 2H, CH2-dppm), 3.68 (s, 1H, −CH CPhMe), 0.27 (s, 3H, CPhMe). 13C{1H} NMR (101 MHz, G
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics CD2Cl2): δ 260.5 (quintet, 2JPC = 12.0 Hz, ReC), 150.3−123.9 (multiple 13C signals of Ph of dppm and the carbyne ligands, and CPhMe overlapped with those of the minor isomer), 57.8−57.2 (m, CH2-dppm), 17.4 (s, CPhMe). Characteristic spectroscopic data of the minor Z isomer are as follows. 31P{1H} NMR (162 MHz, CD2Cl2): δ −43.6 (s). 1H NMR (400 MHz, CD2Cl2): δ 3.62 (s, 1H, −CHCPhMe), 1.06 (s, 3H, CPhMe). 13C{1H} NMR (101 MHz, CD2Cl2): δ 59.0−58.4 (m, CH2-dppm), 25.8 (s, CPhMe). The Re C signal was not located due to its low intensity. ReI{CCHC(OH)Ph2}(dppm)2 (11). [Re(dppm)3]I (1; 0.500 g, 0.341 mmol) and 1,1-diphenyl-2-propyn-1-ol (0.355 g, 1.70 mmol) were placed in a 50 mL Schlenk round-bottom flask connected to a reflux condenser. THF (12 mL) was added. The reaction mixture was refluxed for 12 h to give a dark red solution. The reaction mixture was cooled to room temperature and dried under vacuum. Toluene (15 mL × 2) was used to extract the residue. The extract was filtered to give a dark brown solution. The filtrate was evaporated under vacuum. The residue was washed with diethyl ether (15 mL × 2). The solid was recrystallized in a dichloromethane (2 mL) and diethyl ether (7 mL) mixture to give a brown solid, which was washed with n-hexane and dried under vacuum. Yield: 0.192 g, 43.8%. 31P{1H} NMR (162 MHz, C6D6): δ −39.8 (s). 1H NMR (400 MHz, C6D6): δ 7.65−6.72 (m, 50H, PPh2 and Ph), 5.87−5.84 (br m, 2H, CH2-dppm), 5.74−5.71 (br m, 2H, CH2-dppm), 0.85 (s, 1H, OH), 0.40 (quintet, 4JPH = 6.0 Hz, 1H, CCH). 13C{1H} NMR (101 MHz, C6D6): δ 294.6 (quintet, 2 JPC = 11.2 Hz, ReC), 151.7−124.8 (multiple 13C signals of Ph of dppm and the vinylidene ligands), 116.6 (s, CCH), 69.7 (C(OH)Ph 2 ), 59.8−59.60 (m, CH 2 -dppm). Anal. Calcd for C65H56IOP4Re: C, 60.51; H, 4.38. Found: C, 60.38; H, 4.40. X-ray Crystallography. Single crystals of 2, 9e, 10a, and 11 suitable for X-ray diffraction were grown from CH2Cl2 solutions layered with n-hexane. Intensity data of 2, 9e, and 10a were collected on a Rigaku-Oxford Diffraction SuperNova diffractometer at 100 K, whereas the intensity data of 11 were collected on an Oxford Gemini diffractometer at 173 K. Diffraction data were processed using the CrysAlisPro software (version 1.171.35.19). Empirical absorption corrections were performed using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm in the CrysAlisPro software suite. Structure solution and refinement for all compounds were performed using the Olex2 software package (with embedded SHELXL).35,36 All of the structures were solved by direct methods, expanded by difference Fourier syntheses, and refined by full-matrix least squares on F2. All non-hydrogen atoms were refined anisotropically with a riding model for the hydrogen atoms except as noted separately. Further crystallographic details are summarized in Table S1 in the Supporting Information. Computational Details. All structures were optimized without any constraint at the B3LYP level of density functional theory (DFT).37 The standard 6-31G* basis set was used for O, N, C, and H atoms (unless specified), and the 6-31G** basis set was used for H atoms involved in bond-breaking and -forming processes,38 where the effective core potentials (ECPs) of Lanl2dz were used to describe Re, I, and P atoms,39 with polarization functions for Re (ζ(f) = 0.869), I (ζ(d) = 0.289), and P (ζ(d) = 0.387) being added.40 Frequency calculations were also performed at the same level of theory to identify all the stationary points as minima (zero imaginary frequency) or transition states (one imaginary frequency), as well as to provide free energies at 298.15 K. To reduce the overestimation of the entropy contribution in the gas-phase results, corrections of −2.6 kcal/mol in free energies were made for 2:1 transformations.41 All calculations were performed with the Gaussian 03 software package.42
■
■
Crystallographic data of complexes 2, 9e, 10a, and 11 and NMR spectra (PDF) Cartesian coordinates of all the calculated structures (XYZ) Crystallographic data of complexes 2, 9e, 10a, and 11 (CIF)
AUTHOR INFORMATION
Corresponding Authors
*E-mail for Z.L.:
[email protected]. *E-mail for G.J.:
[email protected]. Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS This work was supported by the Hong Kong Research Grants Council (Project No.: 601812, 602113, CUHK7/CRF/12G-2, 16321516).
■
REFERENCES
(1) For recent general reviews, see for example: (a) Bruneau, C.; Dixneuf, P. H. Metal Vinylidenes and Allenylidenes in Catalysis; WileyVCH: Weinheim, Germany, 2008. (b) Cadierno, V.; Gimeno, J. Chem. Rev. 2009, 109, 3512−3560. (c) Cadierno, V.; Garcia-Garrido, S. E. Top. Organomet. Chem. 2010, 30, 151−218. (2) For reviews, see for example: (a) Esteruelas, M. A.; Lopez, A. M.; Olivan, M. Coord. Chem. Rev. 2007, 251, 795−840. (b) Selegue, J. P. Coord. Chem. Rev. 2004, 248, 1543−1563. (c) Rigaut, S.; Touchard, D.; Dixneuf, P. H. Coord. Chem. Rev. 2004, 248, 1585−1601. (d) Cadierno, V.; Díez, J.; Gamasa, M. P.; Gimeno, J.; Lastra, E. Coord. Chem. Rev. 1999, 193−195, 147−205. (3) For recent examples of osmium chemistry, see: (a) Casanova, N.; Esteruelas, M. A.; Gulias, M.; Larramona, C.; Mascarenas, J. L.; Onate, E. Organometallics 2016, 35, 91−99. (b) Tsui, W. K.; Chung, L. H.; Tsang, W. H.; Yeung, C. F.; Chiu, C. H.; Lo, H. S.; Wong, C. Y. Organometallics 2015, 34, 1005−1012. (c) Bajo, S.; Esteruelas, M. A.; López, A. M.; Oñate, E. Organometallics 2014, 33, 4057−4066. (d) Alos, J.; Bolano, T.; Esteruelas, M. A.; Olivan, M.t; Onate, E.; Valencia, M. Inorg. Chem. 2014, 53, 1195−1209. (e) Vega, E.; Lastra, E.; Gamasa, M. P. J. Organomet. Chem. 2014, 750, 30−34. (f) Bajo, S.; Esteruelas, M. A.; Lopez, A. M.; Onate, E. Organometallics 2012, 31, 8618−8626. (4) For recent examples of ruthenium chemistry, see: (a) JimenezTenorio, M.; Puerta, M. C.; Valerga, P. Organometallics 2016, 35, 388− 399. (b) Skriba, A.; Jasik, J.; Andris, E.; Roithova, J. Organometallics 2016, 35, 990−994. (c) Schauer, P. A.; Skelton, B. W.; Koutsantonis, G. A. Organometallics 2015, 34, 4975−4988. (d) Garcia-de la Arada, I.; Diez, J.; Gamasa, M. P.; Lastra, E. Organometallics 2015, 34, 1345− 1353. (e) Eaves, S. G.; Yufit, D. S.; Skelton, B. W.; Lynam, J. M.; Low, P. J. Dalton Trans. 2015, 44, 21016−21024. (f) Li, T.; Fu, C.; Liu, Z.; Guo, S.; Liu, Z.; Wen, T. B. Organometallics 2015, 34, 3292−3302. (g) Yeung, C. F.; Chung, L. H.; Lo, H. S.; Chiu, C. H.; Cai, J.; Wong, C. Y. Organometallics 2015, 34, 1963−1968. (5) For recent examples of iron chemistry, see: (a) El-Tarhuni, S.; Manhaes, L. M.; Morrill, C.; Raftery, J.; Randhawa, J. K.; Whiteley, M. W. J. Organomet. Chem. 2016, 811, 20−25. (b) Makhoul, R.; Sahnoune, H.; Dorcet, V.; Halet, J.-F.; Hamon, J. R.; Lapinte, C. Organometallics 2015, 34, 3314−3326. (c) Fitzgerald, E. C.; Ladjarafi, A.; Brown, N. J.; Collison, D.; Costuas, K.; Edge, R.; Halet, J. F.; Justaud, F.; Low, P. J.; Meghezzi, H.; Roisnel, T.; Whiteley, M. W.; C. Organometallics 2011, 30, 4180−4195. (d) Lohan, M.; Justaud, F.; Roisnel, T.; Ecorchard, P.; Lang, H.; Lapinte, C. Organometallics 2010, 29, 4804−4817. (e) Byrne, L. T.; Koutsantonis, G. A.; Sanford, V.; Selegue, J. P.; Schauer, P. A.; Iyer, R. S. Organometallics 2010, 29, 1199−1209.
ASSOCIATED CONTENT
* Supporting Information S
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.organomet.6b00568. H
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics (6) (a) Bianchini, C.; Marchi, A.; Marvelli, L.; Peruzzini, M.; Romerosa, A.; Rossi, R. Organometallics 1996, 15, 3804−3816. (b) Bianchini, C.; Marchi, A.; Marvelli, L.; Peruzzini, M.; Romerosa, A.; Rossi, R.; Vacca, A. Organometallics 1995, 14, 3203−3215. (7) Baker, R. J.; Edwards, P. G.; Gracia-Mora, J.; Ingold, F.; Abdul Malik, K. M. J. Chem. Soc., Dalton Trans. 2002, 21, 3985−3992. (8) Valyaev, D. A.; Semeikin, O. V.; Peterleitner, M. G.; Borisov, Y. A.; Khrustalev, V. N.; Mazhuga, A. M.; Kremer, E. V.; Ustynyuk, N. A. J. Organomet. Chem. 2004, 689, 3837−3846. (9) Albertin, G.; Antoniutti, S.; Bordignon, E.; Bresolin, D. J. Organomet. Chem. 2000, 609, 10−20. (10) Ramsden, J. A.; Weng, W.; Gladysz, J. A. Organometallics 1992, 11, 3635−3645. (11) (a) Coletti, C.; Gonsalvi, L.; Guerriero, A.; Marvelli, L.; Peruzzini, M.; Reginato, G.; Re, N. Organometallics 2012, 31, 57−69. (b) Coletti, C.; Gonsalvi, L.; Guerriero, A.; Marvelli, L.; Peruzzini, M.; Reginato, G.; Re, N. Organometallics 2010, 29, 5982−5993. (c) Mantovani, N.; Bergamini, P.; Marchi, A.; Marvelli, L.; Rossi, R.; Bertolasi, V.; Ferretti, V.; de los Rios, I.; Peruzzini, M. Organometallics 2006, 25, 416−426. (d) Mantovani, N.; Brugnati, M.; Gonsalvi, L.; Grigiotti, E.; Laschi, F.; Marvelli, L.; Peruzzini, M.; Reginato, G.; Rossi, R.; Zanello, P. Organometallics 2005, 24, 405−418. (e) Peruzzini, M.; Barbaro, P.; Bertolasi, V.; Bianchini, C.; de los Rios, I.; Mantovani, N.; Marvelli, L.; Rossi, R. Dalton Trans. 2003, 21, 4121−4131. (f) Bertolasi, V.; Mantovani, N.; Marvelli, L.; Rossi, R.; Bianchini, C.; de los Rios, I.; Peruzzini, M.; Akbayeva, D. N. Inorg. Chim. Acta 2003, 344, 207−213. (g) Mantovani, N.; Marvelli, L.; Rossi, R.; Bertolasi, V.; Bianchini, C.; de los Rios, I.; Peruzzini, M. Organometallics 2002, 21, 2382−2394. (h) Bianchini, C.; Mantovani, N.; Marvelli, L.; Peruzzini, M.; Rossi, R.; Romerosa, A. J. Organomet. Chem. 2001, 617−618, 233−241. (i) Bianchini, C.; Mantovani, N.; Marchi, A.; Marvelli, L.; Masi, D.; Peruzzini, M.; Rossi, R.; Romerosa, A. Organometallics 1999, 18, 4501−4508. (12) (a) Peruzzini, M.; Akbayeva, D.; Bianchini, C.; de los Rios, I.; Ienco, A.; Mantovani, N.; Marvelli, L.; Rossi, R. Inorg. Chim. Acta 2002, 339, 202−208. (b) Bianchini, C.; Marchi, A.; Mantovani, N.; Marvelli, L.; Masi, D.; Peruzzini, M.; Rossi, R. Eur. J. Inorg. Chem. 1998, 1998, 211−219. (13) (a) Pombeiro, A. J. L.; Almeida, S. S. P. R.; Silva, M. F. C. G.; Jeffrey, J. C.; Richards, R. L. J. Chem. Soc., Dalton Trans. 1989, 2381− 2387. (b) Pombeiro, A. J. L.; Jeffrey, J. C.; Pickett, C. J.; Richards, R. L. J. Organomet. Chem. 1984, 277, C7−C10. (14) Almeida, S. P. R.; Pombeiro, A. J. L. Organometallics 1997, 16, 4469−4478. (15) Carvalho, M. F. N. N.; Herrmann, R.; Pombeiro, A. J. L. Monatsh. Chem. 1993, 124, 739−749. (16) As a related reaction, the complex [ReCl(CNH2)(dppe)2][BF4 reacts with NBu4OH/PhCCH to give Re(CN)(CCHPh) (dppe)2, presumably through the Re(I) intermediate [ReCl(CN) (dppe)2]−: da Silva, M. F.C. G.; Frausto da Silva, J. J. R.; Pombeiro, A. J. L.; Pellinghelli, M. A.; Tiripicchio, A. J. Chem. Soc., Dalton Trans. 1996, 2763−2772. (17) Li, Y.; Blacque, O.; Fox, T.; Luber, S.; Polit, W.; Winter, R. F.; Venkatesan, K.; Berke, H. Dalton Trans. 2016, 45, 5783−5799. (18) Mantovani, N.; Marvelli, L.; Rossi, R.; Bianchini, C.; de los Rios, I.; Romerosa, A.; Peruzzini, M. J. Chem. Soc., Dalton Trans. 2001, 2353−2361. (19) Casey, C. P.; Ha, Y.; Powell, D. R. J. Organomet. Chem. 1994, 472, 185−193. (20) (a) Xue, W. M.; Wang, Y.; Mak, T. C. W.; Che, C. M. J. Chem. Soc., Dalton Trans. 1996, 2827−2834. (b) Xue, W. M.; Wang, Y.; Chan, M. C. W.; Su, Z. M.; Cheung, K. K.; Che, C. M. Organometallics 1998, 17, 1946−1955. (21) (a) Ozerov, O. V.; Watson, L. A.; Pink, M.; Caulton, K. G. J. Am. Chem. Soc. 2007, 129, 6003−6016. (b) Ozerov, O. V.; Watson, L. A.; Pink, M.; Caulton, K. G. J. Am. Chem. Soc. 2004, 126, 6363−6378. (c) Ozerov, O. V.; Watson, L. A.; Pink, M.; Caulton, K. G. J. Am. Chem. Soc. 2004, 126, 2105−2113. (d) Ozerov, O. V.; Huffman, J. C.; Watson, L. A.; Pink, M.; Caulton, K. G. Organometallics 2003, 22,
2539−2541. (e) Ozerov, O. V.; Watson, L. A.; Pink, M.; Caulton, K. G. J. Am. Chem. Soc. 2003, 125, 9604−9605. (22) (a) Leeaphon, M.; Fanwick, P. E.; Walton, R. A. J. Am. Chem. Soc. 1992, 114, 1890−1892. (b) Leeaphon, M.; Ondracek, A. L.; Thomas, R. J.; Fanwick, P. E.; Walton, R. A. J. Am. Chem. Soc. 1995, 117, 9715−9724. (23) Herrmann, W. A.; Kiprof, P.; Felixberger, J. K. Chem. Ber. 1990, 123, 1971−1974. (24) Additional examples: (a) Fischer, E. O.; Clough, R. L.; Stueckler, P. J. Organomet. Chem. 1976, 120, C6−C8. (b) Fischer, E. O.; Huttner, G.; Lindner, T. L.; Frank, A.; Kreissl, F. R. Angew. Chem., Int. Ed. Engl. 1976, 15, 231−232. (c) Fischer, E. O.; Rustemeyer, P.; Neugebauer, D. Z. Naturforsch., B: J. Chem. Sci. 1980, 35, 1083−1087. (d) Fischer, E. O.; Rustemeyer, P. J. Organomet. Chem. 1982, 225, 265−277. (e) Chiu, K. W.; Howard, C. G.; Wilkinson, G.; Galas, A. M. R.; Hursthouse, M. B. Polyhedron 1982, 1, 803−808. (f) Fischer, E. O.; Chen, J.-B.; Scherzer, K. J. Organomet. Chem. 1983, 253, 231−241. (g) Pombeiro, A. J. L.; Hughes, D. L.; Pickett, C. J.; Richards, R. L. J. Chem. Soc., Chem. Commun. 1986, 246−247. (h) Miguel, D.; Steffan, U.; Stone, F. G. A. Polyhedron 1988, 7, 443−448. (i) Vrtis, R. N.; Rao, C. P.; Warner, S.; Lippard, S. J. J. Am. Chem. Soc. 1988, 110, 2669− 2670. (j) Warner, S.; Lippard, S. J. Organometallics 1989, 8, 228. (k) Handwerker, B. M.; Garrett, K. E.; Nagle, K. L.; Geoffroy, G. L.; Rheingold, A. L. Organometallics 1990, 9, 1562−1575. (l) Terry, M. R.; Mercando, L. A.; Kelley, C.; Geoffrey, G. L.; Nombel, P.; Lugan, N.; Malhieu, R.; Ostrander, R. L.; Owens-Wallermire, B. E.; Rheingold, A. L. Organometallics 1994, 13, 843−865. (m) Williams, D. S.; Schrock, R. R. Organometallics 1994, 13, 2101−2104. (n) Fischer, E. O.; Apostolidis, C.; Dornberger, E.; Fillipou, A. C.; Kanellakopulos, B.; Lungwitz, B.; Mueller, J.; Powietzka, B.; Rebizant, J.; Roth, W. Z. Naturforsch., B: J. Chem. Sci. 1995, 50, 1382−1395. (o) Friedman, L. A.; Harman, W. D. J. Am. Chem. Soc. 2001, 123, 8967−8973. (25) (a) Chen, J.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.; Jia, G. Angew. Chem., Int. Ed. 2011, 50, 10675−10678. (b) Chen, J.; Shi, C.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.; Jia, G. Chem. - Eur. J. 2012, 18, 14128−14139. (26) (a) Rivero, M.; Kremer, C.; Gancheff, J.; Kremer, E.; Suescun, L.; Mombrú, A.; Mariezcurrena, R.; Domínguez, S.; Mederos, A.; Midollini, S. Polyhedron 2000, 19, 2249−2254. (b) Ciani, G.; D’Alfonso, G. D.; Romiti, P.; Sironin, A.; Freni, M. Inorg. Chim. Acta 1983, 72, 29−37. (c) Adams, J. J.; Arulsamy, N.; Sullivan, B. P.; Roddick, D. M.; Neuberger, A.; Schmehl, R. H. Inorg. Chem. 2015, 54, 11136−11149. (27) Senn, D. R.; Wong, A.; Patton, A. T.; Marsi, M.; Strouse, C. E.; Gladysz, J. C. J. Am. Chem. Soc. 1988, 110, 6096−6109. (28) Kolobova, N. E.; Antonova, A. B.; Khitrova, O. M.; Antipin, M. Y.; Struchkov, Y. T. J. Organomet. Chem. 1977, 137, 69−78. (29) Frech, C. M.; Llamazares, A.; Blacque, O.; Schmalle, H. W.; Berke, H. Organometallics 2009, 28, 5333−5340. (30) Additional examples: (a) Weng, W.; Bartik, T.; Johnson, M. T.; Arif, A. M.; Gladysz, J. A. Organometallics 1995, 14, 889−97. (b) Wong, A.; Gladysz, J. A. J. Am. Chem. Soc. 1982, 104, 4948−4950. (31) Shi, C.; Jia, G. Coord. Chem. Rev. 2013, 257, 666−701. (32) (a) Chen, J.; He, G.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.; Jia, G. Organometallics 2010, 29, 2693−2701. (b) He, G.; Fan, T.; Chen, J.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.; Jia, G. New J. Chem. 2013, 37, 1823−1832. (33) (a) Carvalho, M. F. N. N.; Almeida, S. S. P. R.; Pombeiro, A. J. L.; Henderson, R. A. Organometallics 1997, 16, 5441−5448. (b) Almeida, S. S. P. R.; Da Silva, J. J. R. F.; Pombeiro, A. J. L. J. Organomet. Chem. 1993, 450, C7−C8. (c) Amelia, A.; Lemos, N. D. A.; Pombeiro, A. J. L. J. Organomet. Chem. 1988, 356, C79−C82. (d) Pombeiro, A. J. L.; Hills, A.; Hughes, D. L.; Richards, R. L. J. Organomet. Chem. 1988, 352, C5−C7. (e) Pombeiro, A. J. L.; Richards, R. L.; Dilworth, J. R. J. Organomet. Chem. 1979, 175, C17−C36. (34) See for example: (a) O’Hanlon, D. C.; Cohen, B. W.; Moravec, D. B.; Dallinger, R. F.; Hopkins, M. D. J. Am. Chem. Soc. 2014, 136, 3127−3136. (b) Moravec, D. B.; Hopkins, M. D. Chem. - Eur. J. 2013, 19, 17082−17091. (c) Moravec, D. B.; Hopkins, M. D. J. Phys. Chem. I
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics A 2013, 117, 1744−1755. (d) Lovaasen, B. M.; Lockard, J. V.; Cohen, B. W.; Yang, S.; Zhang, X.; Simpson, C. K.; Chen, L. X.; Hopkins, M. D. Inorg. Chem. 2012, 51, 5660−5670. (e) Cohen, B. W.; Lovaasen, B. M.; Simpson, C. K.; Cummings, S. D.; Dallinger, R. F.; Hopkins, M. D. Inorg. Chem. 2010, 49, 5777−5779. (f) Semenov, S. N.; Blacque, O.; Fox, T.; Venkatesan, K.; Berke, H. J. Am. Chem. Soc. 2010, 132, 3115− 3127. (g) Semenov, S. N.; Taghipourian, S. F.; Blacque, O.; Fox, T.; Venkatesan, K.; Berke, H. J. Am. Chem. Soc. 2010, 132, 7584−7585. (h) Sun, J.; Shaner, S. E.; Jones, M. K.; O’Hanlon, D. C.; Mugridge, J. S.; Hopkins, M. D. Inorg. Chem. 2010, 49, 1687−1698. (i) Da Re, R. E.; Hopkins, M. D. Coord. Chem. Rev. 2005, 249, 1396−1409. (35) Sheldrick, G. M. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112−122. (36) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. J. J. Appl. Crystallogr. 2009, 42, 339−341. (37) (a) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B: Condens. Matter Mater. Phys. 1988, 37, 785−789. (b) Becke, A. D. Phys. Rev. A: At., Mol., Opt. Phys. 1988, 38, 3098−3100. (c) Becke, A. D. J. Chem. Phys. 1993, 98, 5648−5652. (38) Huzinaga, S.; Andzelm, J.; Klobukowski, M. R. A.; ESakai, Y.; Tatewaki, H. Gaussian basis sets for molecular calculations; Elsevier: Amsterdam, 1984. (39) (a) Wadt, W. R.; Hay, P. J. J. Chem. Phys. 1985, 82, 284−298. (b) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 299−310. (40) Hollwarth, A.; Bohme, M.; Dapprich, S.; Ehlers, A. W.; Gobbi, A.; Jonas, V.; Kohler, K. F.; Stegmann, R.; Veldkamp, A.; Frenking, G. Chem. Phys. Lett. 1993, 208, 237−240. (41) Benson, S. W. The Foundations of Chemical Kinetics; Krieger: Malabar, FL, 1982. (42) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03, Revision E.01; Gaussian, Inc., Wallingford, CT, 2004.
J
DOI: 10.1021/acs.organomet.6b00568 Organometallics XXXX, XXX, XXX−XXX
