Observation of an unusual amine oxidation reaction during the oxidation and hydrolysis of [(Bu-t)(2)Ga(o-C6H4NMe2)](2): molecular structures of (Bu-t)(2)Ga(o-C6H4NMe2)(mu-OH)-Ga(Bu-t)[o-C6H4N(O)Me-2] and (Bu-t)(2)Ga(o-C6H4NMe2) (O=PPh3)

Reaction of [(Bu-t)(2)Ga(mu-Cl)(2)] with Li(o-C6H4NMe2) yields [(Bu-t)(2)Ga(o-C6H4NMe2](2) (1). The atmospheric oxidation/hydrolysis of 1 results in the isolation of (Bu-t)(2)Ga(o-C6H4NMe2)(mu-OH)Ga(Bu-t) [oC(6)H(4)N(O) Me-2] (2). The structure of compound 2 (as determined by X-ray crystallography) consists of a gallium dimer in which one of the ortho-(dimethylamino)phenyl ligands is oxidized and the other exhibits strong intramolecular O-H ... N hydrogen bonding (Delta G(double dagger)= 57.3 kJ mol(-1)) to the hydroxide bridge. A pathway for the formation of 2 is proposed. Reaction of compound 1 with O=PPh3 results in the formation of the Lewis acid-base complex (Bu-t)(2)Ga(o-ChH(6)NMe(2)) (O-PPh3) (3), whose structure has been confirmed by X-ray crystallography. (C) 1997 Elsevier Science Ltd.