Synthesis and structures of a series of Ge-M (M = C, Si, and Sn) compoundsderived from germyllithium containing three 2-(dimethylamino)phenyl groupson germanium

Reactions of {tris [2-(dimethylamino)phenyl] germyl}lithium (1) with Group 14 electrophiles afford the corresponding carbogermane, silylgermane, and s tannylgermane compounds containing three 2-(dimethylamino)phenyl groups on the germanium atom. X-ray structure analysis of these structures was perfor med and revealed that: (1) the steric repulsion between the amino groups an d the substituents is mainly reflected by the torsion angle M-Ge-C-ipso-C-o rtho; (2) the N...M atomic distances are within the sum of the van der Waal s radii; (3) in a series of the silylgermanes, the Ge-Si bond length increa ses as the size of the silyl group increases: -SiH3 less than or equal to S iMe2H less than or equal to SiMe3 less than or equal to SiMe(2)t-Bu. (C) 19 99 Elsevier Science S.A. All rights reserved.