Collect. Czech. Chem. Commun. 1999, 64, 959-970

Trigold(I) Phosphine Derivatives of Clusters Containing Octahedral Rh2Ru4B-Boride Cores: The X-Ray Structure of [Rh2Ru4(CO)15Rh2Ru4B{AuPCy3}3] (Cy = cyclohexyl)

Andrew D. Hattersleya, Catherine E. Housecroftb,* and Arnold L. Rheingoldc

a University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, U.K.
b Institut für Anorganische Chemie, Spitalstrasse 51, CH-4056, Basel, Switzerland
c Department of Chemistry, University of Delaware, Newark, DE 19716, U.S.A.


The reaction of [Rh(CO)2Cl]2 with [HRu4(CO)12BH]- followed by treatment with an excess (at least three-fold) of [Cy3PAuCl] (Cy = cyclohexyl) leads to the formation of [Rh2Ru4(CO)16B{AuPCy3}] (previously prepared by another route) and [Rh2Ru4(CO)15B{AuPCy3}3]. The new trigold derivative has been characterized by spectroscopic and mass spectrometric methods, and by single crystal X-ray diffraction. It possesses an octahedral Rh2Ru4 core containing an interstitial boron atom; two of the gold(I) phosphine units cap two adjacent faces and the third bridges an edge of the octahedral cage. There are no close Au···Au contacts. Reactions of [Rh2Ru4(CO)16B]- with [(R3PAu)3O]+ (R = Ph, 2-MeC6H4) resulted in the formation of [Rh2Ru4(CO)15B{AuPR3}3]; for R = Ph, two isomers in respect of the arrangements of the AuPPh3 were isolated. Fluxional processes involving the gold(I) phosphine fragments have been observed using solution variable-temperature 31P NMR spectroscopy.

Keywords: Borides; Rhodium clusters; Ruthenium clusters; Crystal structure; Gold(I) phosphines.