Chemistry of methinyltricobalt enneacarbonyls. Part VIII. Friedel–Crafts reactions with halogeno-clusters

Abstract

Friedel–Crafts reactions with halogenomethinyltricobalt enneacarbonyls afford a useful route to a wide range of aryl clusters, RCCo₃(CO)₉. The usefulness of g.l.c. in their purification is emphasised. Substitution is predominately in the para-position but exceptions occur when the aryl substituent is small (e.g. F). In one case (R = ClC₆H₄) both ortho- and para-isomers were isolated. Methods for determining the structure are described and the inductive-mesomeric effects of a Co₃C cluster evaluated.