title: Synthesis and Structural Characterization of (1,4-Dihydropyrid-1-yl)aluminum Complexes.
abstract: The reaction between LiAlH(4) and pyridine, 4-methylpyridine, or 3,5-dimethylpyridine results in hydride transfer to the pyridine ring to give tetrakis(pyridine)lithium tetrakis(1,4-dihydropyrid-1-yl)aluminate(III), 1, tetrakis(4-methylpyridine)lithium tetrakis(1,4-dihydro-4-methylpyrid-1-yl)aluminate(III), 2, or tetrakis(3,5-dimethylpyridine)lithium tetrakis(3,5-dimethyl-1,4-dihydropyrid-1-yl)aluminate(III), 3, respectively. We claim that 1, instead of lithium tetrakis(1,4-dihydropyrid-1-yl)aluminate(III), is the compound which is known as Lansbury's reagent. Treatment of trimethylamine-alane, AlH(3).NMe(3), with pyridine yields tris(1,4-dihydropyrid-1-yl)(pyridine)aluminum, 4. It could be shown that AlH(3).NMe(3) initially reduces pyridine to 1,2-dihydropyridine, which is subsequently converted into its 1,4-isomer. The X-ray crystal structures of 1-4 were determined. While the differences between Al-N distances within each of the compounds 1-3 are not significant, 4 exhibits two distinctly different types of Al-N bonds, the dative bond between Al and N(pyridine), d(Al-N) = 1.959(2) Å, and the covalent bonds between Al and N(1,4-dihydropyrid-1-yl), d(av)(Al-N) = 1.833 Å.
authors.affiliation: Department of Chemistry, The University of Edinburgh, Edinburgh EH9 3JJ, Scotland, U.K.
authors.forename: Karl
authors.initials: K
authors.lastname: Hensen
authors.forename: Alexander
authors.initials: A
authors.lastname: Lemke
authors.forename: Thorsten
authors.initials: T
authors.lastname: Stumpf
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
authors.forename: Holger
authors.initials: H
authors.lastname: Fleischer
authors.forename: Colin R.
authors.initials: CR
authors.lastname: Pulham
authors.forename: Robert O.
authors.initials: RO
authors.lastname: Gould
authors.forename: Steven
authors.initials: S
authors.lastname: Harris