Syntheses, crystal structures and properties of two Cu(II) coordination polymers: Cu(C3N2H4)2(HL)2 and Cu(C3N2H4)2L with C3N2H4 ¼ imidazole, H2L ¼ adipic acid

The reactions of freshly prepared Cu(OH)2·xH2O and Cu(OH)222y(CO3)y·zH2O precipitates with imidazole and adipic acid in CH3OH/H2O at pH ¼ 5.4 yielded Cu(C3N2H4)2(HL)2 1 and Cu(C3N2H4)2L 2, respectively. Complex 1 consists of ribbon-like polymeric chains1 1 [Cu(C3N2H4)2(HL)4/2], in which the octahedrally coordinated Cu atoms are doubly bridged by bis-monodentate hydrogen adipato ligands. The interchain N–H· · ·O hydrogen bonding interactions are responsible for supramolecular assembly of the polymeric chains into open 3D frameworks and two-fold interpenetration of the resulting open frameworks completes the crystal structure of 1. Within complex 2, the Cu atoms are penta-coordinated to form CuN2O3 square pyramids and condensed into Cu2N4O4 dimers, which are doubly bridged by twisted bis-monodentate adipato ligands into polymeric chains 1 1 {[Cu(C3N2H4)2]2L4/2} with 4- and 18-membered rings progressing alternatively. The polymeric chains are assembled due to interchain N–H· · ·O hydrogen bonding interactions. The thermal and magnetic behaviors of 1 and 2 is discussed. q 2004 Published by Elsevier B.V.