The molecular structures of difluorophosphino (disilyl)amine and bis-(difluorophosphino)silylamine in the gas phase, determined by electron diffraction

Abstract

The molecular structures of difluorophosphino (disilyl)amine and bis(difluorophosphino)silylamine in the gas phase have been determined by electron diffraction. Both molecules have planar co-ordination at nitrogen, and Si–N bonds that are substantially longer than those in other silylamines. Principal bonds and angles (r_a) for N(PF₂)(SiH₃)₂ are r(P–F) 158.5(3), r(P–N) 168.0(4), r(Si–N) 175.5(4) pm; FPF 96.9(10), FPN 99.4(7), and SiNSi 119.3(17)°. For N(PF₂)₂(SiH₃) principal parameters are r(P–F) 157.0(2), r(P–N) 169.1(4), r(Si–N) 176.7(7) pm; FPF 96.1 (5), FPN 99.3(3), and PNP 117.6(7)°. In each compound the conformation adopted by the difluorophosphino-groups is such that the axes of the nitrogen and phosphorus lone-pair orbitals are approximately orthogonal.