Synthesis and Characterization of Five-Coordinate Gallium and Indium Complexes Stabilized by Tridentate, Substituted Pyrrole Ligands

Five-coordinate gallium and indium complexes stabilized by tridentate, substituted pyrrole ligands have been synthesized and characterized. The reaction of MCl3 with 1 equiv. of Li[NC4H2(CH2NMe2)2-2,5] in diethyl ether affords [{NC4H2(CH2NMe2)2-2,5}MCl2] [M = Ga (1), In (2)] in high yield. Reaction of 1 with 2 equiv. of MeLi in diethyl ether at −78 °C followed by heating to reflux for 30 min affords the alkylated product [{NC4H2(CH2NMe2)2-2,5}GaMe2] (3). Similarly, the reaction of 2 with 2 equiv. of MeLi or nBuLi affords the dialkylated complexes 4 and 5, respectively. Complex 2 is a strong Lewis acid which readily absorbs H2O forming [{[C4H2N(CH2NMe2)2-2,5]InCl2}2(μ-OH2)] (6). Complexes 3, 4, and 6 have been characterized by X-ray crystallography. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)