Novel long bipyridine-type linking ligands containing an intervening naphthalene fragment:: [Zn(L1)(NO3)2], [Zn(L2)(NO3)2], and [Cd(L1)1.5(NO3)2](L1 = (4-py)-CH=N-C10H6-N=CH-(4-py); L2 = (3-py)-CH=N-C10H6-N=CH-(3-py))

Novel bipyridine-type linking ligands L-1 ((4-py)-CH=N-C10H6-N=CH-(4-py)) and L-2 ((3-py)-CH=N-C10H6-N=CH-(3-py)), a pair of isomers due to possessing different pairs of terminal pyridyl groups, were prepared by the Schiff-base condensation. In ligand L-1, the (NN)-N-... separation between the terminal pyridyl groups is 16.0 angstrom, with their nitrogen donor atoms at the para positions (4,4'). The corresponding (NN)-N-... separation in ligand L-2 is 14.2 angstrom, with the nitrogen donor atoms at the meta positions (3,3'). 1-D zigzag-chain coordination polymers [Zn(L-1)(NO3)(2)] (1) and [Zn(L-2)(NO3)(2)] (2) were prepared by reactions of Zn(NO3)(2) (.) 6H(2)O with ligands L-1 and L-2, respectively, by solution diffusion. Polymer 3, [Cd(L-1)(1.5)(NO3)(2)], prepared from Cd(NO3)(2) (.) 4H(2)O and L-1, exhibits a 1-D ladder structure, whose repeating ladder unit consists of four Cd metals and four L-1 ligands to create a large 76-membered ring with dimensions of 20.8 x 20.8 angstrom. All products were structurally characterized by X-ray diffraction. (c) 2005 Elsevier B.V. All rights reserved.