title: Base Effects on the Formation of Four- and Five-Coordinate Cationic Aluminum Complexes.
abstract: This work was conducted as part of our continuing effort to determine the factors that affect cation formation for organometallic aluminum complexes. In this study, the interactions of R(2)AlX (where R = Me, (i)Bu, (t)Bu; X = Cl, Br, I) with the monodentate bases thf, pyridine, NEt(3), HN(i)Pr(2), H(2)N(i)Bu, H(2)N(t)Bu, and O=PPh(3) are examined to determine the role of the base in cation formation. These reactions resulted in the neutral adducts of the general form R(2)AlX.base (1-6, 8, 10, and 12) as well as the cationic complexes [R(2)Al(base)(2)]X (7, 9, and 11). The reactions of Me(2)AlX (where X = Cl, Br) with PMDETA (N,N',N",N"'-pentamethyldiethylenetriamine) and the catalytic activity of the resulting cationic complexes (13 and 14) are also discussed. All of the compounds were characterized by mp, IR, (1)H-NMR, and elemental analyses, and in one an X-ray crystallographic study was carried out. X-ray data for 13: triclinic, P&onemacr;, a = 6.9542(6) Å, b = 12.2058(10) Å, c = 13.2417(11) Å, alpha = 106.236(2) degrees, beta = 98.885(2) degrees, gamma = 93.807(2) degrees, V = 1059.06(15) Å(3), and Z = 2 for 181 parameters refined on 4358 reflections having F > 6.0sigma(F), R = 0.0697, and R(w) = 0.0697.
authors.affiliation: Department of Chemistry, Center for Main Group Chemistry, North Dakota State University, Fargo, North Dakota 58105.
authors.forename: Jolin A.
authors.initials: JA
authors.lastname: Jegier
authors.forename: David A.
authors.initials: DA
authors.lastname: Atwood