Synthesis, Reactivity, X-ray Crystal Structures and Electrochemical Behaviour of Water-Soluble [Tris(pyrazolyl)borato]ruthenium(II) Complexes of 1,3,5-Triaza-7-phosphaadamantane (PTA)

A series of chloridoruthenium(II) complexes bearing the tripodal ligand tris(pyrazolyl)borate (Tp), the water-soluble cage phosphane 1,3,5-triaza-7-phosphaadamantane (PTA) and its N-boranyl adduct PTA(BH3), together with PPh3, have been synthesised. The corresponding monohydrido complexes have also been obtained by treating the chlorides with NaOMe. The X-ray crystal structures of [TpRuCl(PTA)(PPh3)] (2) and [TpRuCl(PTA)2] (3) are also described. Cyclic voltammetry (CV) studies in MeCN and dmso generally show reversible RuII/III oxidation waves and the values of E1/2 ox reflect the electron-donating character of the ligands [Tp (each arm) PTA PTA(BH3)], whose Lever electrochemical parameter (EL) has been estimated for the first time