Synthesis and coordination ability of the first phosphavinyl(selenoxo)phosphorane: an electronic story

The Mes*P[double bond, length as m-dash]C(Cl)-P([double bond, length as m-dash]Se)(i-Pr)₂ phosphavinyl(selenoxo)phosphorane is the first derivative of this new class of compounds embedding in the same unit a λ ² P(iii) and a λ ⁴ P(v) atom. This electron-rich compound is a good candidate for new coordination compounds, but also for potential biologic applications. The coordination ability of the phosphavinyl(selenoxo)phosphorane derivative towards transition metals was evaluated by means of both experimental and theoretical analyses. Along with the gold and palladium complexes, we report here the first copper(ii) coordination compound stabilised with a phospha(chalcogenoxo)phosphorane type ligand as well as a heterobimetallic gold and copper containing derivative stabilised with two phospha(selenoxo)phosphorane units. Density functional theory (DFT) calculations, coupled with natural bond order (NBO), energy decompostion analysis (EDA) and unrelaxed bond dissociation energy (UBDE) analyses were systematically performed to gain insight into the electronic structure of targeted compounds, and to understand wheter the type of the chalcogen atom influences the coordination behaviour of the P[double bond, length as m-dash]C-P[double bond, length as m-dash](X) moiety (X = O, S or Se). The selenium compound demonstrated no impact on cell viability, while exerting a clear protective effect through the reduction of oxidative stress while the Se-Au compound significantly reduced cell viability in the same experimental setting.