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Issue 11, 1984
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Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 31. Synthesis and crystal structures of the compounds [AuW(µ-CHR)(CO)2(PPh3)(η-C5H5)]·CH2Cl2 and [AuPtW(µ3-CR)(CO)2(PMe3)3(η-C5H5)][PF6](R = C6H4Me-4)

Abstract

Treatment of a mixture of the salts [N(PPh3)2][W2{µ-CH(C6H4Me-4)}(CO)7(η-C5H5)] and TIPF6 in tetrahydrofuran (thf) with [AuCl(PPh3)] affords the bridged p-tolylmethylidene complex [AuW{µ-CH(C6H4Me-4)}(CO)2(PPh3)(η-C5H5)], the structure of which has been established by a single-crystal X-ray diffraction study. As expected, the Au–W bond [2.729(1)Å] is spanned by the CH(C6H4Me-4) group. The µ-C–W separation is relatively short [2.058(14)Å] whereas the µ-C–Au distance is relatively long [2.268(14)Å]. To account for these features a three-centre two-electron µ-C–Au–W interaction is postulated. Addition of [Au(PR′3)]+[PR′3= PPh3 or P(cyclo-C6H11)3] fragments, generated in situ from [AuCl(PR′3)] and TIPF6 in dichloromethane, to the alkylidynetungsten compounds [W([triple bond, length half m-dash]CR)(CO)2(η-C5H5)](R = C6H4Me-4 or Me) affords the salts [AuW(µ-CR)(CO)2(PR′3)(η-C5H5)][PF6][R = C6H4Me-4, PR′3= PPh3or P(C6H11)3; R = Me, PR′3= PPh3]. N.m.r. studies (1H, 31P-{1H}, and 13C-{1H}) on solutions of these salts, however, reveal that the cations dissociate, affording equilibrium mixtures containing the species [Au{W([triple bond, length half m-dash]CR)(CO)2(η-C5H5)}2]+ and [Au(PR′3)2]+. The trimetal compound [AuPtW(µ3-CR)(CO)2(PMe3)3(η-C5H5)][PF6](R = C6H4Me-4) has been prepared by two routes: from the reaction between [Au{W([triple bond, length half m-dash]CR)(CO)2(η-C5H5)}2][PF6] and [Pt(C2H4)(PMe3)2], and by addition of [Au(thf)(PMe3)][PF6] to [PtW(µ-CR)(CO)2(PMe3)2-(η-C5H5)]. The structure of [AuPtW(µ3-CR)(CO)2(PMe3)3(η-C5H5)][PF6] has been established by X-ray crystallography. A triangular array of metal atoms [Au–W 2.801 (2), Au–Pt 2.956(2), and Pt–W 2.770(2)Å] is asymmetrically bridged by the CR ligand [µ3-C–Au 2.21 (4), µ3-C–Pt 1.97(4), and µ3-C–W 2.01 (4)Å]. The Au–Pt separation suggests that there is little or no direct metal–metal bonding between these two metal atoms. The tungsten atom carries the cyclopentadienyl ligand and two CO groups, but the latter are appreciably non-linear. The gold and platinum atoms are ligated by one and two PMe3 groups, respectively.

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Article information


J. Chem. Soc., Dalton Trans., 1984, 2545-2551
Article type
Paper

Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 31. Synthesis and crystal structures of the compounds [AuW(µ-CHR)(CO)2(PPh3)(η-C5H5)]·CH2Cl2 and [AuPtW(µ3-CR)(CO)2(PMe3)3(η-C5H5)][PF6](R = C6H4Me-4)

G. A. Carriedo, J. A. K. Howard, F. G. A. Stone and M. J. Went, J. Chem. Soc., Dalton Trans., 1984, 2545
DOI: 10.1039/DT9840002545

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