Structure and reactivity of transition metal substituted dichloroantimony and dichlorobismuth complexes

Abstract

The dichloro Group 15 complexes [{Cp^x(CO)₂Fe}BiCl₂] (Cp^x = Cp,  η⁵-C₅H₃tBu₂ {Cp′′}) 1a, b and [{Cp′′(CO)₂Fe}SbCl₂] 3 are prepared. The crystal structure determination of 1b and 3 shows a polymeric chlorine bridged structure for the bismuth complex 1b whereas for the antimony compound 3 a molecular structure with weak intermolecular chlorine bridges is found. The reaction of 1a or 3 with magnesium leads to the threefold transition-metal substituted complexes [(μ₃-E){Fe(CO)₂Cp^x}₃] (5: E = Bi, Cp^x = Cp; 7: E = Sb, Cp^x = Cp′′), whereas the analogous reaction of 1b results in the disubstituted bismuth chloro complex [{Cp′′(CO)₂Fe}₂BiCl] 6. Finally, the reaction of an equimolar mixture of 1a and 3 with magnesium yields the novel antimony-bridged compound [(μ₃-Sb){Fe₂(μ-CO)(CO)₂Cp₂}{Fe(CO)₂Cp′′}] 8.