Reactivity of “GaI” Toward N-Substituted 1,4-Diazabuta-1,3-dienes:  Synthesis and Characterization of Gallium Heterocycles Containing Paramagnetic Diazabutadiene Monoanions

The paramagnetic heterocycles (R = 2,6-dimethylphenyl ( 1 ), 2,4,6-trimethylphenyl ( 2 ), and 2,6-diisopropylphenyl ( 3 )) were obtained by reaction of “GaI” with Xyl-dab ( N,N ‘ - bis[2,6-dimethylphenyl]-1,4-diazabuta-1,3-diene), Mes-dab ( N,N ‘ - bis[2,4,6-trimethylphenyl]-1,4-diazabuta-1,3-diene), and Dipp-dab ( N,N ‘ - bis[2,6-diisopropylphenyl]-1,4-diazabuta-1,3-diene), respectively. Compounds 1 − 3 were characterized structurally by X-ray crystallography. ESR investigations of 3 and quantum chemical calculations for the parent system were carried out to provide information on the bonding. The reaction of 1 with 1 equiv of the 1,4-dilithiated Xyl-dab led to the formation of Ga(Xyl-dab) 2 ( 4 ) with one singly and one doubly reduced ligand; this compound was also characterized by X-ray crystallography.