Crystal structure of bis[di(chloromethyl)phosphinato]copper(II) tetrahydrate

The crystal structure of the complex CuL2 . 4H(2)O, where HL is di(chlorome thyl)phosphinic acid O(OH)P(CH2Cl)(2), is studied by X-ray diffraction. The Cu atom has an elongated tetragonal-bipyramidal coordination (4 + 2); it i s coordinated by two O atoms of the two trans-arranged monodentate L ligand s (average Cu-O(L), 1.937 Angstrom) and four O(w) atoms of the water molecu les. The axial Cu-O(w) bonds are on the average 0.658 Angstrom longer than the equatorial bonds (2.619 and 1.961 Angstrom, respectively). The complex molecules in the crystal are united by an extended system of hydrogen bonds O(w)-H(w)O...(L) and O(w)-H(w)...O(w) involving the terminal O(L) atoms of both ligands and four water molecules.