Coordination chemistry of P, O-bidentate phosphinophenolates with Ga3+ and In3+

Abstract

Novel complexes of Ga³⁺ and In³⁺ were synthesized with two hetero donor phosphinophenolate ligands (PO⁻, ortho-phenoxydiphenylphosphine; MePO⁻, 5-methyl-2-phenoxydiphenylphosphine). RPO⁻ (R = H, Me) binds in a bidentate fashion through both the hard O and the soft P donor atoms to In³⁺, whereas, it only binds Ga³⁺ through the O donor. Electrochemical synthesis proved to be a practical synthetic approach to In₂(PO)₃Cl₃, In(PO)₃ and In(MePO)₃. [In(MePO)(H₂O)Cl₂]₂ and Ga(HPO)Cl₃ were synthesized from MCl₃ (M = In and Ga, respectively). Both dimetallic indium complexes, [In(MePO)(H₂O)Cl₂]₂ and In₂(PO)₃Cl₃, incorporate phenolate oxygen atoms bridging the two metal ions. Each pair of In atoms are in a distorted octahedral geometry in each complex, with the former complex having a coordination sphere of PO₃Cl₂ for both indium metal ions and the latter showing a coordination sphere of PO₃Cl₂ for one indium and P₂O₃Cl for the other. Ga(HPO)Cl₃ is a zwitterionic complex, with Ga having a OCl₃ coordination core. All these complexes were fully characterized by a variety of techniques including X-ray crystallography.