Unexpected gold-containing boride clusters formed from the reactions of [RhRu3H(η5-C5Me5)(CO)9BH]– with gold(I) phosphine derivatives: crystal structures of [RhRu3H(η5-C5Me5)(CO)9B{Au(PPh3)}2(AuCl)]·CH2Cl2 and [RhRu3H(η5-C5Me5)(CO)9B{Au2(dppf)}(AuCl)]·CH2Cl2[dppf = 1,1′-bis(diphenylphosphino)ferrocene]

Abstract

The deprotonation of [RhRu₃H(η⁵-C₅Me₅)(CO)₉BH₂] occurred by loss of an M–H–B bridging hydrogen atom to give [RhRu₃H(η⁵-C₅Me₅)(CO)₉BH]^–1; indirect evidence suggests the Rh–H–B proton has been removed. Anion 1 reacts with [AuCl(PPh₃)] or [Au₂Cl₂(dppf)][dppf = 1,1′-bis(diphenylphosphino)ferrocene] to yield [RhRu₃H(η⁵-C₅Me₅)(CO)₉B{Au(PPh₃)}₂(AuCl)]2 and [RhRu₃H(η⁵-C₅Me₅)(CO)₉B{Au₂(dppf)}(AuCl)]3 respectively rather than expected derivatives of the type [RhRu₃(η⁵-C₅Me₅)(CO)₉BH_{3 –x}(AuL)_x](x= 1, 2 or 3). The single crystal structures of 2·CH₂Cl₂ and 3·CH₂Cl₂ have been determined: 2·CH₂Cl₂, monoclinic, space group P2₁/c, a= 11.944(4), b= 40.870(6), c= 13.313(4)Å, β= 108.66(2)°, Z= 4, R= 0.0684; 3·CH₂Cl₂, monoclinic, space group P2₁/c, a= 11.919(2), b= 39.350(8), c= 13.520(4)Å, β= 108.62(2)°, Z= 4, R= 0.0584. The trigold derivative [RhRu₃(η⁵-C₅Me₅)(CO)₉B{Au(PPh₃)}₃] was formed either by treating 1 with [{Au(PPh₃)}₃O][BF₄] or treating 2 with PPh₃ in the presence of Tl[PF₆] or [N(PPh₃)₂]Cl. The chloride ligand in compound 2 was replaced by iodide through reaction with [NEt₄]I. Anion 1 also reacted with [Au₂Cl₂(dppa)][dppa = bis(diphenylphosphino)acetylene] to give the linked dicluster species [{RhRu₃H(η⁵-C₅Me₅)(CO)₉B(AuCl)}₂{µ-Au(dppa)Au}₂].