Molecular structure of [Me2Al(μ-OPh)]2:: A crystallographic and ab initio study

The molecular structure of [Me2Al(mu-OPh)](2) has been determined. The phenoxide ring is parallel to the Al2O2 ring rather than the energetically favored perpendicular configuration determined by ab initio calculations. Ab initio calculations successfully predict the structures of sterically demanding analogs. The adoption of the parallel configuration allows for an estimation of the magnitude of crystal packing forces. A discussion of the parameters controlling the structures of dialkylaluminum phenoxides is presented. Crystal data: group Pbca, a = 12.127(2), b = 8.491(2), c = 17.299(4) angstrom, V = 1781.3(6) angstrom(3), Z = 4, R = 0.0695, wR(2) = 0.1390.