Isometallocenes. Part 1. Polymethylated isocobaltocenium salts; a general route to [Co(C4Me4)(arene)]

Abstract

The formation of tricarbonyl(tetramethylcyclobutadiene)cobalt hexafluorophosphate and its conversion into the neutral complexes [{Co(CO)₂(C₄Me₄)}₂] and [Co(CO)₂(C₄Me₄)I] are described. Reaction of the latter with arenes in the presence of aluminium chloride provides a general route to the cations [Co(C₄Me₄)(arene)]⁺ of which seven new examples are described. Some carbonyl substitutions of the cation [Co(CO)₃(C₄Me₄)]⁺ are also reported.