The open-chain triphosphanes RMe2SiCH2P(PR′2)2 (R = Me, Ph; R′ = SiMe3, Cy, Ph)

Abstract

The triphosphanes RMe₂SiCH₂P(PR′₂)₂ (R = Me, Ph; R′ = SiMe₃, Cy) are synthesised in good yield viametathesis of organodichlorophosphanes and LiPR′₂, while for R′ = Ph a propensity to form (Ph₂P)₂ precludes isolation of the in situ characterised triphosphanes. Where R = Me and R′ = SiMe₃ the triphosphane has also been characterised by single crystal X-ray diffraction and exhibits a single geometric conformer in the solid state, though solution-phase NMR spectra are indicative of facile conformational exchange across a wide temperature range. All of the described triphosphanes exhibit comparable behaviour, with their respective ³¹P{¹H} NMR spectra manifesting anomalous ‘second-order’ characteristics, which are considered using full spin-Hamiltonian simulation. Preliminary studies of coordination chemistry and ancillary reactivity of the triphosphanes are described.