SYNTHESIS AND CHARACTERIZATION OF THE FIRST BORANE ADDUCTS AND BORON CATIONS OF SOME N-ALKYL AND N-AMINOTRIPHENYLPHOSPHORANIMINES

Abstract

Abstract The first borane adducts of N-alkyl and N-aminotriphenylphosphoranimines, Ph3P[dbnd]N—R, were prepared by two different general synthetic methods. The first method involved displacement of THF (tetrahydofuran) from THF-borane by the free imines, and the second employed the reaction of LiBH4 with iminium bromides, Ph3P[dbnd]N(R)HBr, in diethyl ether. Imine boranes, Ph3P[dbnd]N(R)BH3, were synthesized where R [dbnd] methyl, ethyl, n-propyl, isopropyl, isobutyl, t-butyl. dimethylamino, phenylamino, and methyl, phenylamino as the nitrogen attached groups. Symmetrical boron cations, (Ph3P[dbnd]NR)2, BH2 +, where R = methyl, ethyl, and n-propyl, were synthesized by displacement of iodide from in-situ generated iodoborane adducts, Ph3P[dbnd]N(R)BH2I, by the free imines. An attempt to form an unsymmetrical boron cation from (CH3)3 NBH2I and Ph, P[dbnd]N(n-C3H7) resulted only in a mixture of the corresponding symmetrical boron cations. Physical, chemical and spectral properties of the borane adducts and b...