Ligand and Metal Effects on the Formation of Main Group Polyhedral Clusters

The reaction of AlMe3 or ZnMe2 with hppH (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) and then with tBuLi affords [Li8(H)m(hpp)6]n+[X] -n, X = [ZntBu3], m = n = 1 (the cation core of which is shown); X = [Li(Me2AltBu2)2, m = 0, n = 2, as the major product in each case. These data reveal that non-aromatic heterocycle hppH and ZnMe2 can be employed to generate novel hydride-encapsulation main-group-metal clusters, and that related polylithium architectures can also incorporate a central void.