Impact of Coordinated Pseudohalide Ions and Picolinamide on Supramolecular Synthons in Selected Zinc and Cadmium Complexes

Four new Zn and Cd picolinamide (pia) complexes with cyanate and azide ions, namely [Zn(NCO)(2)(pia)(2)] (1), [Cd(NCO)(2)(pia)](n) (2), [Zn(N-3)(2)(pia)(2)] (3) and [Cd(N-3)(2)(pia)](n)center dot nH(2)O (4), have been prepared and characterized by IR and NMR spectroscopy, and thermal (TG/DTA) methods. For the compounds 1 and 3 X-ray analysis revealed mononuclear molecular structure with octahedral N4O2 environment around the zinc(II) center with cis-arrangement of ligands. Only in 1 the amide head-to-head supramolecular motifs, represented by an R-2(2)(8) designator, are observed, while in 3 none of the typical amide motifs were found. While the IR data suggest the polymeric structures for 2 and 4 in the solid state, all the NMR spectral data support the monomeric structure of the compounds in the solution.