Synthesis and structures of some bimetallic (Li/Ca, Li/Zn, Li/Li) diamides derived from 1,2-bis(neopentylamino) benzene and of Li2[{N(SiMe2NPri2)}2C6H4-1,2](thf)3

The following crystalline, or microcrystalline ( 4), metal diamides have been prepared under mild conditions from the N,N'-disubstituted 1,2- diaminobenzene [{N(R)H}(2)C6H4-1,2] (H2L:R = CH2But; H2L': R = SiMe2NPr2i):[Li(thf)(mu-L)(mu-I)Ca(thf)] (1), [Li(thf)(4)][{Zn(mu-L)}(3)(mu(3)-Cl)] (2), [Li(thf)(4)][Zn(L)(2)] (3), [{Li(OEt2)(mu-L)Zn}(2)(mu-L)] (4), [Li(OEt2)(mu-L)Zn(mu-L)Zn(LH)] (5) and [Li(thf)(mu-L')Li(thf)(2)] (6). Compounds 1-5 were obtained from [Li-2(L)] and CaI2 (1) or ZnCl2 (2-5) while 6 was derived from H-2(L') and LiBun. Compound 5 was isolated as a very minor by-product from the synthesis of 4, and is assumed to have been formed there from by adventitious hydrolysis. The green salt 3 was paramagnetic with the negative charge uniformly delocalised on the two ligands. The other compounds were colourless and diamagnetic. The X-ray structures of each, except 4, are reported and discussed.