Gallane-coordinated transition metal complexes and related compounds

The gallane-Lewis base adduct H3Ga center dot L is employed as a sigma-Ga-H ligand for the group 6 carbonyl metal complexes (OC)(5)M(H3Ga center dot L) (M = Cr, Mo, W) and the manganese complex Cp*(OC)(2)Mn(H3Ga.L). Group 6 carbonyl metal derivatives (OC)(5)M(H3Ga center dot L) are synthesized by the reaction of (OC)(5)M(THF) and H3Ga center dot L. The photochemical reaction of Cp*(OC)(3)Mn and H3Ga center dot L affords the gallane manganese sigma-complex Cp*(OC)(2)Mn(H3Ga center dot L). The structural properties of these complexes can be understood in terms of the coordination mode of sigma-Ga-H bond to (OC)(5)M and Cp*(OC)(2)Mn fragments being depicted as eta(1)-HGaH2 center dot L and eta(2)-HGaH2 center dot L, respectively. The contribution of sigma-donation from the Ga-H sigma-bond to d(sigma) orbital on M occurs in both systems, however, the participation of pi-back donation from filled d(pi) orbital to Ga-H sigma* orbital is negligible for the (OC)(5)M(H3Ga center dot L) complexes but important for Cp*(OC)(2)Mn(H3Ga center dot L) complex. Such distinctive characteristics of the sigma-H3Ga center dot L ligand provides a sharp contrast to that of H3B center dot L and silane ligands. (C) 2010 Elsevier B.V. All rights reserved.