New 1-and 2-dimensional polymeric structures of cyanopyridine complexes of AgI and CuI

Polymeric transition metal chalcogenides have attracted much attention because of their possible unusual properties directly derived from their extended structures. The molecules n-cyanopyridine (n = 2, 3, and 4) and pyridine-3,4-dicarbonitrile are found to function as bidentate or monodentate (only pyridine nitrogen donor atom) ligands in the coordination of silver(I) and copper(I) ions, respectively. The mode of coordination depends on the anion and the crystallization conditions and has been elucidated in all cases by single-crystal X-ray crystallography. We report here the syntheses, structural characterization, and electrical properties of six new polymers, [Ag-2(2-cyanopyridine)(2)(NO3)(2)](n) (1), [Ag-4(3-cyanopyridine)(8)(SiF6)(2)(H2O)(2)]n (2), [Ag(3-cyanopyridine)(2)(NO3)](n) (3), [Ag(pyridine-3,4-dicarbonitrile)(2)(NO3)](n) (4), [Cu-I(4-cyanopyridine)(2)(SCN)](n) (5), and [Cu-I(pyridine-3,4-dicarbonitrile)(2)(SCN)](n) (6). Compounds 1 and 2 exhibit novel two-dimensional networks, while 3-6 have one-dimensional chain structures, in which 3 is a single-stranded helix. Room-temperature conductivities of 1, 2, 4, and 6 have been measured and are 3.1 x 10(-7), 2.7 x 10(-7), 7.4 x 10(-6), and 4.3 x 10(-5) S(.)cm(-1), respectively. The effect of temperature on the conductivities has been investigated.