The Organic and Hydride Chemistry of Transition Metals

Abstract

This chapter discusses the organic and hydride chemistry of transition metals. Olefin complexes and metal carbonyls were not considered to be organometallic compounds, any more than were the complex cyanides. The trans–directing effects of ligands in the substitution reactions of platinum complexes resemble superficially the directing effects in aromatic chemistry, ligands of high-trans effect corresponding to strongly ortho-para-directing substituents. The higher alkyl platinum complexes were less stable because of the elimination of olefin with the formation of a platinum hydride complex, but this was only discovered years later; the platinum hydride complexes had not even been thought of when the methyls were isolated. The series of phosphine-stabilized alkyl and aryl complexes was extended to include those of octahedral configuration, and the organo derivatives of rhodium, ruthenium, osmium, and rhenium were obtained. In the middle of the 1950s, the only transition-metal hydride complexes definitely identified were those containing carbon ligands in addition to the hydride ligand. Infrared spectroscopy had failed to demonstrate its presence in the metal carbonyl hydrides, and nuclear magnetic resonance (NMR) spectroscopy was just beginning. Diphenylacetylene was readily available for such experiments.