Aluminum, gallium and copper complexes of 2,2-dimethyl-1,3-propanediamine

Reaction of M(tBu)3 (M=Al, Ga) with 2,2-dimethyl-1,3-propanediamine (dmpa-H4) yields the thermally stable Lewis acid–base complexes (tBu)3M(dmpa-H4), M=Al (1) and Ga (2), respectively. The reaction of 2 with Ga(tBu)3 yields the formation of [(tBu)3Ga]2(dmpa-H4) (3). In contrast, reaction of dmpa-H4 with AlMe3 yields the tri-aluminum compounds [Al3Me5(dmpa-H2)2] (4). Reaction of dmpa-H4 with CuCl2 in MeOH–THF yields the neutral complex, [Cu(dmpa-H4)2Cl2] (5), while the reaction in the presence of NaBPh4 and MeCN yields the ionic complex [Cu(dmpa)2(MeCN)2][BPh4]2 (6). Compound 6 may also be formed directly from compound 5. The molecular structures of compounds 2–6 have been determined by X-ray crystallography.