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-diphenylhydrazine, Ph(H)N-N(H)Ph, or elemental sulfur in toluene affords the dimeric crystalline products [Np2Al-N(H)Ph]2, I, and [Np2Al-SNp]2, II, respectively. The etherate of triphenylalumium, Ph3Al·OEt2, when allowed to react with 2-aminobiphenyl, yields the dimer [Ph2AL-N(H[Ph′]2, (Ph′ = Biphenyl) III. Each compound has been characterized by 1H NMR, elemental analysis, and single crystal X-ray diffraction. I and II crystallize in the monoclinic space group P21/n (No. 14); I: a = 9.801 (3), b = 20.490 (9), c = 17.569 (8) Å, β = 97.81 (3)°, V = 3496 (3) Å3 for Z = 4; II: a = 10.191 (5) Å, b = 10.907 (5) Å, c = 16.779 (6) Å, β = 97.18 (3)°, V = 1851 (1) Å8 for Z = 2. Refinement of I converged at R = 0.051, R w = 0.049, while refinement of II converged at R = 0.051, R w = 0.066. III crystallizes in the tetragonal space group l41/a (No. 88); a = 26.628 (5) Å, c = 11.017 (4) Å, V = 7812 (4) Å3, 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 rings with Al-N bond distances ranging from 1.978 (8) to 1.992 (8) Å for I, Al-S distances ranging from 2.353 (2) to 2.364 (2) Å for II, and Al-N distances of 1.983 (7) and 1.946 (6) Å for III. Further pyrolysis of these products did not yield higher oligomers.