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.