Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 114. Ditungsten–digold compounds having two W(CC6H4Me-4)(CO)2(η5-C2B9H9Me2) fragments linked by AuP(Ph)2(CH2)n(Ph)2PAu (n= 2–6) groups
Abstract
Treatment of 1 equivalent of the reagent [NEt4][W(CR)(CO)2(η5-C2B9H9Me2)](R = C6H4Me-4), in the presence of TlBF4, with 0.5 equivalent of the compounds [Au2Cl2{µ-Ph2P(CH2)nPPh2}](n= 2–6) in CH2Cl2 affords the complexes [W2Au2(µ-CR)2{µ-Ph2P(CH2)nPPh2}(CO)4(η5-C2B9H9Me2)2]. The crystal structure of the species with n= 4 has been determined by X-ray crystallography, confirming that the molecule has two RCW(CO)2(η5-C2B9H9Me2) fragments bridged by an AuP(Ph)2CH2CH2CH2CH2(Ph)2PAu unit, with a centre of inversion at the midpoint of the chain of methylene groups. The W–Au bonds [2.798(1)Å] are asymmetrically bridged by the p-tolylmethylidyne ligands [W–µ-C 1.870(9), Au–µ-C 2.194(9)Å]. In a similar manner, the compounds [W2Au2(µ-CR)2(µ-Z or E-Ph2PCHCHPPh2)(CO)4(η5-C2B9H9Me2)2] have been prepared from reactions between the gold compounds [Au2Cl2(µ-Z or E-Ph2PCHCHPPh2)] and the salt [NEt4][W(CR)(CO)2(η5-C2B9H9Me2)]. Addition of [Pt(cod)2](cod = cycloocta-1,5-diene) to the complexes [W2Au2(µ-CR)2{µ-Ph2P(CH2)nPPh2}(CO)4(η5-C2B9H9Me2)2] affords the chain cluster compounds [W2Pt2Au2(µ3-CR)2{µ-Ph2P(CH2)nPPh2}(CO)4(cod)2(η5-C2B9H9Me2)2]. The NMR data (1H, 13C-{1H}, 31P-{1H} and 11B-{1H}) for the new complexes are reported and discussed.