The chemistry and the stereochemistry of poly (N-alkyliminoalanes) : XI. The crystal and molecular structure of the hexamer (HAlN-n-Pr)6 and the octamer (Haln-n-Pr)8

Abstract The crystal and molecular structures of the hexamer, (HAlN-n-Pr) 6 (I) and octamer (HAlN-n-Pr) 8 (II) have been determined by the Patterson procedure and by direct methods, respectively, using tridimensional X-ray diffraction data collected by counter methods. The block-matrix least-squares refinement led to a final R value of 5.7% for I and 5.8% for II. The molecular framework of I, (AlN) 6 , is shaped as a hexagonal prism, while that of II, (AlN) 8 , may be derived from a combination of such a hexameric cage with a square ring of a dimer. The main average bond lengths A are: AlN, 1.913(11) for I and 1.916(2) for II; NC, 1.508(5) and 1.516(4); AlH, 1.53(2) and 1.50(2), respectively. Crystal data: I, trigonal space group P3; a 16.801(2), c 9.647(2) A; Z - 3; II, triclinic space group P1, a 21.99(1), b 10.58(1), c 9.75(1)A, α 97.7(5), β 91.9(5), γ 100.3(5)°; Z = 2.