Models of rhodium complexes bound to silica: preparation, structure and interconversion of dinuclear silyloxyrhodium complexes

(μ-Ph3SiO)2Rh2(COD)2 (2; COD = 1,5-cyclooctadiene) and (μ2-Ph3SiO)2Rh2(CO)4 (4) were prepd. by bridging ion metathesis and interconverted by terminal ligand exchange reactions. (μ2-Me3SiO)2Rh2(COD)2 was obtained alternatively by silylation of the bridging coordinated OH groups in (μ2-OH)2Rh2(COD)2 by N,N-bis(trimethylsilyl)-trifluoroacetamide. The crystal and mol. structure of 2 and 4 (R = Ph) derivs. was detd. by x-ray diffraction. Both complexes show a double square planar roof-like structure with roof angle ω = 109.6° (2) and 126.5° (4).