Binuclear organometallic compounds. Part V. Insertion into M–C and H–C bonds of co-ordinatively unsaturated transition-metal fragments: synthesis of group VIA metal cyclopentadienyltricarbonyl metallates (germanium and tin) and hydrides

Abstract

The reactions of Me₃M¹–C₅H₅(M¹= Si, Ge, and Sn) with low oxidation state, co-ordinatively unsaturated transition metal substrates are divided into: Class (I), oxidative addition–elimination; Class (II), oxidative cleavage; and Class (III), reactions as ligands. Class (I) systems are described in detail for M¹= Ge and Sn reacting with M²(MeCN)₃(CO)₃(M²= Cr, Mo, and W), to yield M²(π-C₅H₅)(Me₃M¹)(CO)₃. Reactivity decreases for a given M¹ in the sequence Cr > Mo ≈ W, and Sn > Ge Si (unreactive) for a given M². The same Group VIA reactivity order is observed for the related reactions of C₅H₅ and M²(MeCN)₃(CO)₃ to afford M²H(π-C₅H₅)(CO)₃; these are recommended as the most convenient of the available syntheses of such metal hydrides. Optimal reaction conditions are prescribed.