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 coordinati on polymers, {[Cu(H(2)oao)(L(2,4))]. H2O}(n) (2) and {[Cu(H(2)oao)(Hoa o)].(HL(2,2))}(n) (3) (H(2)oao = oxamide oxime; H(2)L(1,2) = maloic ac id; H(2)L(2,4) = succinic acid; H(2)L(2,2) = maleic acid), have been s ynthesized and their structures have been X-ray crystallographically c haracterized. 1 crystallizes in the monoclinic, space group P2(1)/c wi th 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 i n 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 coordi nated H(2)oao and L(1,2)(2-). Additional hydrogen bonds link the layer s 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) Angst rom(3) and Z = 4. The Cu(II) ions in 2 are bridged by L(2,4)(2-) coord inated in an amphimonodentate mode, forming a one-dimensional zigzag c hain. 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. Furt her weak hydrogen bonds link another chain, and an extended three-dime nsional hydrogen bonding network runs through the crystal. 3 crystalli zes 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 dicarb oxylic acid, L(2,2)(2-) in 3 is not coordinated to the Cu(II) ions. Th e 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 adja cent chains to form sheets, which are sandwiched between uncoordinated HL(2,2)(-) layers, resulting in a segregated double sheet structure i n the crystal. The obtained structures are greatly associated with the size of the spacers, which link the carboxylate groups in the dicarbo xylic acids, and hydrogen bonding interactions between the ligands.