THIA AND AZA BASED ALANES - SYNTHESIS AND MOLECULAR-STRUCTURE OF [NP2AL-N(H)PH]2, [NP2AL-SNP]2, AND [PH2AL-N(H)PH']2 (NP = ME3CCH2- PH = BIPHENYL)

Reaction of trineopentylaluminum, NP3Al (NP = Me3CCH2-), with 1,2-diph enylhydrazine, Ph(H)N-N(H)Ph, or elemental sulfur in toluene affords t he dimeric crystalline products [NP2Al-N(H)Ph]2, I, and [NP2Al-SNP]2, II, respectively. The etherate of triphenylalumium, Ph3Al.OEt2, when a llowed to react with 2-aminobiphenyl, yields the dimer [Ph2AL-N(H[Ph'] 2, (Ph' = Biphenyl) III. Each compound has been characterized by H-1 N MR, elemental analysis, and single crystal X-ray diffraction. I and II crystallize in the monoclinic space group P2(1)/n (No. 14); I: a = 9. 801 (3), b = 20.490 (9), c = 17.569 (8) angstrom, beta = 97.81 (3)-deg rees, V = 3496 (3) angstrom3 for Z = 4; II: a = 10. 191 (5) angstrom, b = 10.907 (5) angstrom, c = 16.779 (6) beta = 97.18 (3)-degrees, V = 1851 (1) angstrom8 for Z = 2. Refinement of I converged at R = 0.051, R(w) = 0.049, while refinement of II converged at R = 0.05 1, R(w) = 0 .066. III crystallizes in the tetragonal space group 14(1)/a (No. 88); a = 26.628 (5) angstrom, c = 11.017 (4) angstrom, V = 7812 (4) angstr om3, for Z = 8. Refinement of III converged at R = 0.065, R(w) = 0.058 . All compounds reside about planar Al2Z2 (Z = N, S) four-membered rin gs with Al-N bond distances ranging from 1.978 (8) to 1.992 (8) angstr om for I, Al-S distances ranging from 2.353 (2) to 2.364 (2) angstrom for II, and Al-N distances of 1.983 (7) and 1.946 (6) angstrom for III . Further pyrolysis of these products did not yield higher oligomers.