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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, Rw = 0.049, while refinement of II converged at R = 0.051, Rw = 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, Rw = 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.

The organoaluminum complex [(C4H9)2Al{N(CH2CH2O)3}A1(C1)]2, I, was prepared by reaction of an excess of (i-C4H9)2AlH with triethanolamine, N(CH2CH2OH)3. I crystallizes in the triclinic space group P1 with unit cell parameters a = 10.246(4), b = 12.864(4), c= 14.681(6)Å, α= 104.96(3), β=89.92(3), γ = 96.84(3)d`, V= 1855 Å3 and Dc= 1.24gcm-3 for Z = 2. Least-squares refinement based on 3745 observed reflections with intensities I>3s`(I) in the range 3.50 < 20 < 45.0d`converged at R=0.080, RW=0.099. I contains two triethanolamine ligands bridged by four Al fragments. The two core Al atoms are six-coordinate residing in octahedral environments. The mean Al-C distance in I is 1.978(9) A while the Al-O distances range from 1.798(4) to 1.931(5) Å. The crystalline product [(CH3)Ga-[14]aneN4]Cl2, II, isolated from reaction of (CH3)3Ga with [14]aneN4, crystallizes in the monoclinic space group P21/c with unit cell parameters a=13.853(5), b=10.755(4), c=13.147(5) Å, β=113.80(3)d`V=1792Å3 and Dc=1.48gcm-3 for Z = 4. Least-squares refinement based on 1832 observed reflections with intensities I > 3s`(I) in the range 3.50 < 20 < 45.0d`converged at R = 0.076, Rw = 0.100. The Ga atom associated with the macrocycle is six-coordinate residing in a distorted octahedral environment. The mean Ga-N distance in II is 2.08(l) Å while the Ga-C bond distance is 1.982(14) Å. The chlorine atoms observed in I and II appear to have resulted from solvent participation of methylene chloride.

The crystalline organoaluminum macrocyclic ligand complex [Al(CH3)3]4[12]aneS4 was prepared by reaction of the sulfur-based crown ether_ with trimethylaluminum in toluene. The title compound crystallizes in the triclinic space group P1 with unit cell parameters a α 8.548(2), b α 9.949(3), c α 11.225(3)Å, α α 64.08(2), β α 78.55(2), γ α 86.96(3)d`, V α 840Å3, and Dc α 1.04gcm-3 for Z α 1. Least-squares refinement based on 1761 observed reflections (I ≥ 3s`(I)) in the range 3.50d`< 20 < 45.0d`converged at R α 0.034, Rw α 0.044. The molecule is situated about a crystallographic centre of symmetry with the four sulfur atoms constituting a plane. As evidenced by the independent distances of 2.530(1) Å and 2.500(1) Å, the A1-S interactions in the organoaluminum complex are rather substantial. Particularly significant is the fact that the conformation of the macrocycle in the title compound is endodentate as the four sulfur atoms are directed towards the interior of the macrocyclic cavity even as it accommodates four trimethylaluminum units.

The macrocyclic salt [H2[14]aneN4H2]Cl4 was prepared and its X-ray crystal structure was determined. The salt crystallizes in the orthorhombic space group Pnna with unit cell parameters a α 14.257(11), b α 7.796(5), c α 17.785(9) Å3, V = 1976.8(2) Å3, and Dc α 1.28gcm-3 for Z α 4. Least-squares refinement based on 1086 observed reflections (I > 3s`(I)) converged at R α 0.055 (Rw α 0.075). The macrocyclic cation is in an unusual exodentate conformation. Additionally, the X-ray crystal structure of the uncomplexed macrocyclic tetradentate secondary amine [14]aneN4 was determined. The neutral macro-cycle crystallizes in the triclinic space group P1 with unit cell parameters a α 4.698(3), b α 8.683(5), c α 15.388(12) Å, α α 90.63(6), β α 97.38(6), γ α 98.99(5)d`, V α 614.6(8) Å3, and Dc α 1.08 gem-3 for Z α 2. Least-squares refinement based on 1458 observed reflections (I >3s`(I)) converged at R α 0.086 (Rw α 0.116). The endodentate conformation of the neutral macrocycle is stabilized by intramolecular hydrogen bonding by two aza-hydrogen atoms to the remaining two nitrogen atoms. The macrocyclic salt was shown to interact with trimethylaluminum resulting in an organoaluminum host-guest compound capable of accommodating 9.7 toluene molecules per anionic site.

The organoaluminum complex [Al(CH3)]2[15]aneN4[Al(CH3)3]2 was prepared by reaction of an excess of trimethylaluminum with the macrocyclic tetradentate secondary amine [15]aneN4 in toluene. Isolated as large, colourless, extremely air-sensitive, prismatic crystals, [Al(CH3)]2[15]aneN4[Al(CH3)3]2 was characterized by single crystal X-ray diffraction: the title compound crystallizes in the monoclinic space group P21/n with unit cell parameters a = 10.826(2)Å, b = 18.221(5) Å, c = 13.825(4)Å, β = 102.23(2)°, V = 2665.3Å3 and Dc = 1.09gcm-3 for Z = 4. Least-squares refinement based on 2064 observed reflections converged at R = 0.056, Rw = 0.065. The distortion displayed by the macrocycle is quite extensive. A planar four-membered Al2N2 ring occupies the central cavity of the macrocycle. The mean Al-N distance in the Al2N2 fragment is 1.958(5)Å while the mean Al-N-Al angle is 90.6(2)°. The Al … Al contact is 2.785(3)Å.

The trietheylaluminum based ferrocenylalane (η5-C5H5)Fe[η5-C5H4Al2(C2H5)4Cl] was prepared from the reaction of triethylaluminum with chloromercuriferrocene in toluene and characterized by single crystal X-ray diffraction. The compound crystallizes in the triclinic space group P1 with unit cell dimensions a = 9.353(3) Å, b = 10.281(7) Å, c = 11.599(9) Å, α = 79.64(7)°, β = 69.41(6)°, γ = 84.33(4)°, and Z = 2 for Dc = 1.27 g cm-3. Full-matrix least-squares refinement has led to a final R factor of 0.068 based on 1866 independent observed reflections. The two diethylaluminum units are bridged by a chlorine atom and one carbon atom of a cyclopentadienyl group, thus forming an Al-Cl-Al-C ring. The four-membered ring is planar to within 0.02 Å. The Al-Cl distances are 2.404(4) Å and 2.266(5) Å. The Al-Cl-Al angle is 78.9(1)° while the Al-C-Al angle is 91.3(4)°. No significant aluminum-iron interaction is observed (Al… Fe = 3.137(4) Å).