Solvent-dependent assembly of mixed-metal N,N '-diphenyl-benzamidinate oxide and alkoxide complexes

The sequential reaction of ZnMe2 with N,N'-diphenylbenzamidine (=HAm 10), L iBut and molecular oxygen affords various lithium triorganozincate species, the identity of which depend upon the solvent conditions used. In the pres ence of THF, the isolated product is a dimer [THF . Li(Me)OZnAm2](2) 12, wh erein oxygen has formally inserted into the Zn-C bond of a MeZnAm2- anion. Compound 12 is based on a (ZnO)(2) ring core with exocyclic alkali metal ce ntres. In the absence of donor solvent, crystals are obtained of both the p seudo-octahedral oxide-encapsulation complex (mu (6)-O)(Li2ZnAm3)(2) 13 and the heterobimetallic alkoxide polymer [(LiOBut)(MeZnOBut)(3)](infinity) 14 . The structures of 12-14 all suggest a predilection for mu (3) oxygen-capp ed triangulated metal arrays in oxophilic mixed Li- Zn systems.