Synthesis, structural characterization and computational studies of catena-poly[chlorido[μ3-(pyridin-1-ium-3-yl)phosphonato-κ3 O:O′:O′′]zinc(II)]

Abstract

Coordination polymers are constructed from two basic components, namely metal ions, or metal-ion clusters, and bridging organic ligands. Their structures may also contain other auxiliary components, such as blocking ligands, counter-ions and nonbonding guest or template molecules. The choice or design of a suitable linker is essential. The new title zinc(II) coordination polymer, [Zn(C5H5NO3P)Cl] n , has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction and vibrational spectroscopy (FT–IR and FT–Raman). Additionally, computational methods have been applied to derive quantitative information about interactions present in the solid state. The compound crystallizes in the monoclinic space group C2/c. The four-coordinated ZnII cation is in a distorted tetrahedral environment, formed by three phosphonate O atoms from three different (pyridin-1-ium-3-yl)phosphonate ligands and one chloride anion. The ZnII ions are extended by phosphonate ligands to generate a ladder chain along the [001] direction. Adjacent ladders are held together via N—H...O hydrogen bonds and offset face-to-face π–π stacking interactions, forming a three-dimensional supramolecular network with channels. As calculated, the interaction energy between the neighbouring ladders is −115.2 kJ mol−1. In turn, the cohesive energy evaluated per asymmetric unit-equivalent fragment of a polymeric chain in the crystal structure is −205.4 kJ mol−1. This latter value reflects the numerous hydrogen bonds stabilizing the three-dimensional packing of the coordination chains.