OXAMIDE OXIME-BASED COPPER(II) COORDINATION POLYMERS - 2-DIMENSIONAL AND 3-DIMENSIONAL STRUCTURES CONTROLLED BY DICARBOXYLATES

The new Cu(II) complex, [Cu(H(2)oao)(L(1,2))(H2O)] (1), and coordination polymers, {[Cu(H(2)oao)(L(2,4))]. H2O}(n) (2) and {[Cu(H(2)oao)(Hoao)].(HL(2,2))}(n) (3) (H(2)oao = oxamide oxime; H(2)L(1,2) = maloic acid; H(2)L(2,4) = succinic acid; H(2)L(2,2) = maleic acid), have been synthesized and their structures have been X-ray crystallographically characterized. 1 crystallizes in the monoclinic, space group P2(1)/c with a = 10.186(1), b = 6.648(1), c = 14.748(3) Angstrom, beta = 102.06(1)degrees, U = 976.5(3) Angstrom(3) and Z = 4. The mononuclear units in 1, in which L(1,2)(2-) chelates to Cu(II) ions, are linked to form a two-dimensional sheet structure through hydrogen bonds between coordinated H(2)oao and L(1,2)(2-). Additional hydrogen bonds link the layers to form a three-dimensional hydrogen bonding network. 2 crystallizes in the monoclinic, space group P2(1)/n with a = 14.739(4), b = 9.994(3), c = 7.101(2) Angstrom, beta = 98.52(2)degrees, U = 1034.4(5) Angstrom(3) and Z = 4. The Cu(II) ions in 2 are bridged by L(2,4)(2-) coordinated in an amphimonodentate mode, forming a one-dimensional zigzag chain. The water of crystallization is hydrogen bonded to both L(2,4)(2-) and H(2)oao of an adjacent chain, forming a two-layered sheet. Further weak hydrogen bonds link another chain, and an extended three-dimensional hydrogen bonding network runs through the crystal. 3 crystallizes in the monoclinic, space group P2(1)/c, with a = 14.817(3), b = 13.693(4), c = 7.328(2) Angstrom, beta = 101.10(2)degrees, U = 1459.1(7) Angstrom(3) and Z = 4. In contrast to the case of 1 and 2, the dicarboxylic acid, L(2,2)(2-) in 3 is not coordinated to the Cu(II) ions. The axial coordination of the oximate oxygen in an adjacent Hoao to [Cu(H(2)oao)(Hoao)](+) leads to the formation of a one-dimensional zigzag chain. The chains are linked by hydrogen bonds between H(2)oao on adjacent chains to form sheets, which are sandwiched between uncoordinated HL(2,2)(-) layers, resulting in a segregated double sheet structure in the crystal. The obtained structures are greatly associated with the size of the spacers, which link the carboxylate groups in the dicarboxylic acids, and hydrogen bonding interactions between the ligands.