STEREOCHEMISTRY OF POLYNUCLEAR COMPOUNDS OF MAIN GROUP ELEMENTS .X. MU-DIPHENYLAMINO-MU-METHYL-TETRAMETHYLDIALUMINUM

µ-Diphenylamino-µ-methyl-tetramethyldialuminum, (CH 3)5 A12N(C6H5)2, has been prepared and the crystal and molecular structure determined from three-dimensional X-ray data collected by counter methods. The structure has been refined by a full-matrix least-squares technique to a final R1 factor of 4.4% on F. The complex crystallizes in the space group C52h-P21/c of the monoclinic system, with four molecules in a cell of dimensions α = 7.850 Å, b = 10.61 µ, c = 21.855 µ; β = 91.74°. The basic structural feature of the complex is a nonplanar four-membered heterocyclic ring system composed of two aluminum atoms, one carbon atom, and one nitrogen atom. (CH3)5A12N(C6H5)2 consists of molecules resembling those found in [A1(CH3)3]2 but with one bridging methyl group removed and a diphenylamino group substituted in its place. The geometry around each A1 atom is distorted from tetrahedral symmetry. The A1(1)-N-A1(2) bridge angle is 85.6°, while the Al(1)-C(5)-A1(2) bridge angle is 78.9°. The average bond lengths are: Al-N, 2.00 Å; Al-C(bridge), 2.14 Å; and Al-C(terminal), 1.95 Å. The presence of the diphenylamino group in the bridging position increases the metal-metal distance from 2.60 Å for [A1(CH3)3]2 to 2.72 Å for this complex. The overall symmetry of the molecule is very nearly C5-m. © 1969, American Chemical Society. All rights reserved.