Structural studies on mesitylaluminum addition compounds

Article abstract of DOI:10.1021/om00001a067

Four mesitylaluminum derivatives, Mes₃Al·(4-picoline)(C₇H₈)0.5 (1), EtMes₂Al·THF (2), Mes₂-ClAl·THF (3), and [Mes₂Al(μ-Cl)]₂ (4) (Mes = 2,4,6-trimethylphenyl), have been prepared and their structures determined by single crystal X-ray diffraction methods. Compound 1 crystallizes in the monoclinic space group C2/c (No. 15): a = 43.784(15) A?, b = 8.901(1) A?, c = 16.760(2) A?, β = 104.02(2)°, Z = 8, R = 10, and R_w = 9.9. Compound 2 crystallizes in the orthorhombic space group P2₁2₁2₁ (No. 19): a = 12.057(9) A?, b = 13.490(3) A?, c = 14.037-(2) A?, Z = 4, R = 5.4, and R_w = 3.9. The halide derivative 3 crystallizes in the primitive monoclinic space group P2₁/a (No. 14): a = 17.18(1) A?, b = 14.754(2) A?, c = 17.316(2) A?, β = 92.74(3)°, Z = 8, R = 6.5, and R_w = 2.4. The base-free compound 4 exists as a dimer and crystallizes in the space group P2₁/c (No. 14): a = 12.288(2) A?, b = 15.824(3) A?, c = 9.095(2) A?, β = 108.43(2)°, Z = 4, R = 5.4, and R_w = 5.9. The distortion associated with 1, 2, and 3 relative to the parent monomeric molecule, Mes₃Al, is discussed with respect to substitution of the mesityl group for the Cl and Et ligands.