Mono- and Bimetallic Alkynyl Metallocenes and Half-Sandwich Complexes: A Simple and Versatile Synthetic Approach

A general process for the synthesis of alkynyl mono and dimetallic metallocenes and half-sandwich complexes has been developed. This approach uses the addition of lithium derivatives of sandwich or half-sandwich complexes to arylsulfonylacetylenes. The reaction occurs in two steps (lithiation and anti-Michael addition to alkynylsulfone followed by elimination of the ArSO₂ moiety) to form the corresponding mono- or bimetallic alkynes in clearly higher yields, simpler experimental procedures, and more environmentally benign conditions than those of the so far reported for the synthesis of this type of products. The electrochemical properties of the newly obtained complexes have also been studied.