Complexes of tripodal phosphine ligands: synthesis, structure and catalytic activities in the hydroboration of C0$_2$

Abstract : Tripodal ligands play a major role in transition metal chemistry by increasing the stability of their complexes and enabling a fine control of the reactivity at the metal center through their steric and electronic properties and their specific coordination geometry. Among those ligands, triphos (MeC(CH$_2$PPh$_2$)$_3$) has attracted considerable attention these years as it was successfully used for several appJlcations in catalysis, including CO$_2$ hydrogenation, disproportionation of formic acid and reduction of amides. Because small changes within a ligand can induce different outcomes lin a catalytic reaction, variations on the triphos backbone have been reported. We report here the use of PhSi(CH$_2$PPh$_2$)$_3$ and its phosphinite derivative PhSi(OPPh$_2$)$_3$ in the coordination chemistry of first-row transition metals with iron(ll), cobalt(lI) and copper(l) (scheme 1).