Penta-, hexa-, and hepta- coordinated cationic metal complexes of trimethyl phosphate

Abstract

Interaction of trimethyl phosphate (TMP) with metal perchlorates in triethyl orthoformate leads to the formation of cationic complexes of the types: [M(TMP) 6] n+ (M = Mg(II), Ca(II), Al(III), Cr(III), Fe(III), [Ce(TMP) 6(OClO 3] 2+, [M(TMP) 5] 2+ (M = Mn, Fe, Co, Cu, Zn) and [Ni(TMP) 5 (H 2O)] 2+. The pentacoordinated Mn(II), Fe(II), Co(II) and Cu(II) complexes are of the high-spin type. The new complexes were characterized by means of spectral, magnetic, conductance and X-ray powder diffraction studies. A distorted O h symmetry was assigned to the hexacoordinated cationic complexes, and a symmetry closer to C 4 v than D 3 h to the pentacoordinated complex cations. Solid-state and solution electronic spectra are discussed and compared to those reported for complexes of neutral organophosphoryl esters. Steric effects influencing the stabilization of higher-coordinated cationic metal complexes become more favorable as the number of methoxy substituents in ligands of the type RR′ 2PO(R,R′ = CH 3 or CH 3O) increases.