Influence of noncovalent intermolecular interactions on crystal packing: syntheses and crystal structures of three layered Zn(ii)/1,2,4-triazole/carboxylate coordination polymers

Abstract

Three 2D layered zinc coordination polymers: Zn(trz)(HBDC) (1), Zn₄(trz)₄(4-FBA)₄·(H₂O)_0.5 (2) and Zn₄(trz)₄(4-CBA)₄ (3) (trz = 1,2,4-triazole, H₂BDC = 1,3-benzenedicarboxylic acid, 4-HFBA = 4-fluorobenzoic acid and 4-HCBA = 4-chlorobenzoic acid) have been synthesized by hydrothermal reactions and characterized by IR, elemental analysis, TGA measurements and X-ray single-crystal analysis. Compounds 1–3 have the same 2D layer constructed by zinc(II) with trz and carboxylate. The main difference in the structure of the three compounds is the interactions between the layers. Compound 1 shows unusual intermolecular hydrogen bonding and C–O⋯π interactions, compound 2 exhibits intermolecular hydrogen bonding and C–F⋯π interactions, while compound 3 only shows intermolecular C–Cl⋯π interactions. It is found that the noncovalent intermolecular interactions have an influence on crystal packing.