Synthesis and properties of protonated methylammonium bis(1-hydroxyethane-1,1-diphosphonato)cuprates(II). Crystal structure of (CH3NH3)(2)[Cu(H2O)(H2L)(2)]center dot H2O

The methods of preparation of the copper(II) complexes with 1-hydroxyethane -1, 1-diphosphonic acid (H4L), (CH3NH3)CuH5L2. 2.5H(2)O (I) and (CH3NH3)(2) Cu(H2L)(2). nH(2)O [n = 6 (II) and 2 (III)], are suggested, and the propert ies of these complexes are described. The structure of compound III is dete rmined by X-ray crystallography. The two cis-position ed H2L2- ligands in t he anionic [Cu(H2O)(mu(2)-H2L)(H2L)](2-) complex have different functionali ties: bidentate-chelate and tridentate chelate-mu(2)-bridging. The Cu atoms are united into a centrosymmetric dimer by a pair of bridge H2L2- ligands. The Cu atom is bonded to five O(L) atoms of three ligands and one O(w) ato m of a water molecule (in the axial position), which are located in the ver tices of a stretched tetragonal bipyramid (4 + 2). Bond lengths: Cu-O(L) 1. 961-1.997 Angstrom (eq), Cu-O(L) 2.354 Angstrom (ax), and Cu-)(w) 2.330 Ang strom.