Treatment of LiAlH4/OEt2 solutions with bulky trialkylphosphine hydrochloride salts or phosphine and then ethereal HCl yields thermally stable phosphine-alane adducts, viz. [H3Al.P(C6H11)3] (10), (H-3Al)n.(PPri2CH2)2 (n = 1 (11), 2 (12)), and [(H3Al)2.{P(C6H11)2CH2}2] (13), which have been shown to be four-coordinate (10 and 13, Al-P = 2.467 (1), 2.460 (2) angstrom) or polymeric (13) with trigonal-bipyramidal aluminum centers (P apical) with exceptionally long Al-P bonds (2.732 angstrom (mean)). Ab initio calculations on the model species H3Al.PH3 (Al-P = 2.605 angstrom) give a stabilization energy of 13.2 kcal/mol relative to AlH3 and PH3, and dimerization to dialane, H2Al(mu-H)2AlH2, and PH3 is favored by 5.84 kcal/mol.
Chloride and phosphide-substituted gallium hydrides: [Cy<sub>3</sub>PGaH<sub>3 –n</sub>Cl<sub>n</sub>]n= 1 or 2, and trimeric [{H<sub>2</sub>Ga(µ-PCy<sub>2</sub>)}<sub>3</sub>]
作者:F. M. Elms、G. A. Koutsantonis、C. L. Raston
DOI:10.1039/c39950001669
日期:——
Thermally robust chlorogallanes, CY3PGaH2Cl 1and Cy3PGaHCl22, accessible by redistribution reactions involving Cy3PGaH3 and Cy3PGaCl3(Cy = cyclohexyl) or 1via anhydrous HCl reaction with Cy3PGaH3, show phosphine but not chlorideâhydride exchange in aromatic solvents; treatment of 1 with [Li(PCy2)(thf)n] affords trimeric [H2Ga(µ-PCy2)}3]3, which crystallises in a twist-boat conformation.