New cadmium(II) and zinc(II) coordination polymers derived from a pyridine-hydrazone block: Self-assembly generation, structural and topological features, and theoretical analysis

A new series of cadmium(II) and zinc(II) coordination polymers, formulated as {[Cd-1.5(mu-L)(mu-CH(3)C00) (mu-N-3)(CH3OH)].3CH(3)OH)(n) (1), {[Zn(mu-L)Br].CH3OH}(0) (2), ([Zn(mu-L)I].CH3OH}(n) (3), {[Zn(mu-L)(N3)]. C2H6OH}(n) (4), and [Zn-2(mu-L)(2) (mu-N-3](n) (5), was self -assembled from the metal(II) acetates (or nitrates), a multifunctional pyridine-hydrazone building block (HL = 2-benzoylpyridine-isonicotinoylhydrazone), and auxiliary ligands selected from NaN3, KBr, or KI. All products 1-5 were isolated as stable crystalline solids and were fully characterized by elemental analysis, IR spectroscopy, and single -crystal X-ray diffraction. Although in all compounds the pyridine-hydrazone blocks L1- simultaneously act as 11 -spacers and N2,0-chelators (adopting the enolic = N-N=C-0 form), the structures of 1-5 are modulated by the type of an auxiliary ligand and thus vary from ladder-like double chains in 1 and zigzag 1D chains in 2-4 to intricate 2D layers in 5. Topological analysis of the underlying metal-organic networks revealed the 2C1 (in 2-4) and hcb (in 5) topologies, while a decorated ladder was identified in 1. Besides, the structure of 1 revealed an interesting example of cyclic hexameric (CH3OH)(6) clusters formed by H-bonding interactions between adjacent methanol molecules of crystallization. The role of hydrogen bonds, it. " it interactions, and presence of solvent molecules of crystallization was analyzed from the structural data and by Hirshfeld surface analysis. (C) 2016 Elsevier B.V. All rights reserved.