Chemistry of methinyltricobalt enneacarbonyls. Part V. Tertiary phosphine and arsine derivatives

Abstract

Mono-, di-, and tri-substituted tertiary phosphine and arsine derivatives of methinyltricobalt enneacarbonyls have been prepared. The co-ordination behaviour of the cluster is determined by the apical substituent Y, and the stereochemistry adopted is one which minimizes nonbonded carbonyl interactions. Thus the majority of mono-substituted complexes have the same structure as MeCCo₃(CO)₈Ph₃P but other MeCCo₃(CO)₈L compounds adopt a carbonyl-bridged configuration. Di- and tri-substituted complexes also have a bridged structure. Different types of structural isomerism in solution have been identified.