Coordination of bis(2-pyridyl)phosphinic acid as a tridentate ligand. Crystal structure of the {bis(2-pyridyl)phosphinato}{tris(2-pyridyl)-phosphine oxide}ruthenium(II) cation, [Ru{py2P(O)O}{py₃PO}]BF4·₂H₂O

Abstract

In the synthesis of the bis{tris(2-pyridyl)phosphine oxide}ruthenium(II) cation, [Ru(py₃P=O)₂]²⁺, the species {bis(2-pyridyl)phosphinato}{tris(2-pyridyl)phosphine oxide}ruthenium(II), [Ru{py₃P=O}-{py₂P(O)O}]⁺, was also isolated. The latter cation has been characterized by a structural determination and is the first example of a tridentate phosphinate anion. The electrochemical and spectral properties of both cations are reported. Crystals of [Ru{py₂P(O)O}{py₃PO}]BF₄·H₂O crystallize in the monoclinic space group P2₁/n with unit cell dimensions a=16.128(7), b=11.493(6), c=17.576(11) Å, β=102.64(4)°, V=3178.9 Å3, Z=4. The structure was refined by a full-matrix least-squares procedure, and converged with R=0.107 and Rw=0.108 for 1172 reflections.