Four- and Five-coordinate Gallium Complexes Stabilized by Bidentate 2-(Dimethylaminomethyl)pyrrole Ligand: Molecular Structures of Ga[NC4H3(CH2NMe2)-2]3 and GaMe2[NC4H3(CH2NMe2)-2]

[[abstract]]Treatment of GaCl3 with one equiv of Li[NC4H3(CH2NMe2)-2] (n=1, 2, 3) in diethyl ether at -78℃ yields GaCl(subscript 3-11)[NC4H3(CH2NMe2)-2](subscript n) (n=1, 1; n=2, 2; n=3, 3). Compound 1 reacts with two equiv of RN to afford GaR2 [NC4H3(CH2NMe2)-2] (4a, R=Me; 4b, R=Bu) via transmetallation. Reacting 2 with one equiv of RLi in diethyl ether, 3 and 4 are formed via ligand redistribution. Variable temperature 1H NMR spectroscopic experiments reveal that the five-coordinate gallium compound 3 is fluxional and results in a coalescence temperature at 5℃, at which AG is calculated at ca. 10.4 Kcal/mole. All the new compounds have been characterized by 1H and 13C NMR spectroscopy and the structures of compounds 3 and 4a have also been determined by X-ray crystallography