REACTION OF ANIONIC OXYGEN DONORS WITH THE ANTITUMOR COPPER(II)-PYRIDINE-2-CARBALDEHYDE THIOSEMICARBAZONE (HL) SYSTEM AND THE CRYSTAL-STRUCTURE OF )][H2PO4](2)CENTER-DOT-2H(3)PO(4)CENTER-DOT-2H(2)O

The complexes [(CuL)(2)(XO4)]. nH(2)O (HL = pyridine-2-carbaldehyde th iosemicarbazone, X = HP, n = 6; X = Mo, n = 1), [{CuL(ptp)}(2)]. 4H(2) O (Hptp = p-tritylphenol) and [{CuL(tip)}(2)] (Htip = 2,4,6-triiodophe nol) have been prepared from the reaction of aqueous solutions of [{Cu L(CH3CO2)}(2)] with salts of the appropriate oxygen donor. Also prepar ed were [{Cu(HL)(H2PO4)}(2)][H2PO4](2) . xH(3)PO(4) . nH(2)O (x = 0, n = 3; x = 2, n = 2) from the reaction of [{CuL(CH3CO2)}(2)] with 2 mol dm(-3) H3PO4 and phosphate species (arising from the hydrolysis of 2 mol dm(-3) HPF6) respectively. The complexes have been characterized b y a range of physicochemical techniques and the crystal and molecular structure of [{Cu(HL)(H2PO4)}(2)][H2PO4](2) . 2H(3)PO(4) . 2H(2)O dete rmined by single-crystal X-ray diffraction. The complex cation is a ce ntrosymmetric dimer, the monomeric units having one-atom bridges from two H2PO4- anions. The copper atom has a distorted square-pyramidal ge ometry with three donor atoms (NNS) from the neutral, tridentate HL li gand and the fourth in-plane donor (an oxygen) from the bridging anion . The fifth position is occupied by a less strongly bound oxygen from the second bridging anion. An extensive hydrogen-bonding scheme involv ing the bridging H2PO4- anions, non-co-ordinated H2PO4- anions, H3PO4 moieties, water molecules and ligand exists with one very strong conta ct of 2.436 Angstrom. These complexes may serve as simple models for t he interaction of this antitumour system with oxygen donors.