Reductive preparation of bis(arene)metal complexes from metal halides in solution using potassium atoms

Abstract

Some known bis(arene) complexes of zerovalent Ti, V, Cr, and Mo have been synthesised in a new way by stepwise reduction of solutions of the metal chlorides in tetrahydrofuran and arene, using K atoms condensed into the solutions at –110 °C under vacuum in a rotary reactor. The extent of reduction was followed by observing colour changes in the solutions. With Ti and V, the initial products were anionic forms of the bis(arene) complexes, which were oxidised to give the zerovalent compounds. The method is a useful way of making 0.1–1 g samples of some bis(arene)titanium complexes and bis(naphthalene) complexes of V, Cr, and Mo which are otherwise accessible only by using the transition-metal atoms as reagents.