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

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 In-2(PO)(3)Cl-3, In(PO)(3) and In(MePO)(3). [In(MePO)(H2O)Cl-2](2) and Ga(HPO)Cl-3 were synthesized from MCl3 (M = In and Ga, respectively). Both dimetallic indium complexes, [In(MePO)(H2O)Cl-2](2) and In-2(PO)(3)Cl-3, 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)Cl-3 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.