Novel CuI coordination polymer self-assembled from 2,5-bis(pyridin-4-yl)-1,3,4-oxadiazole and thiocyanate ions: Synthesis, structural characterization, Hirshfeld surface analysis, thermal and magnetic studies

Abstract

The synthesis and crystal structure of one-dimensional (1-D) coordination polymer from an angular dipyridyl ligand 2,5-bis(pyridine-4-yl)-1,3,4-oxadiazole (4-pox) and CuCl2⋅2H2O, [CuI(4-poxH)(SCN)(μ1,3-SCN)]n (named complex 1), are reported. The investigated copper(I) complex crystallizes in the monoclinic crystal system with space group P21/n. UV–vis and FTIR suggest the co-presence of the 4-pox ligand and the pseudohalide, in the isolated complex. This was confirmed by a crystallographic study which shows that the copper is in a tetrahedral environment, linked to two thiocyanate groups and to two nitrogen atoms, one belonging to the pyridine ring and the others to thiocyanate group. The crystallographic study also reveals the protonation of the unbound organic ligand pyridine. The crystal cohesion is assured by different intermolecular hydrogen bonds, π–π stacking, and coordination bonds (N–Cu and S–Cu). Therefore, the one-dimensional coordination chains are further interconnected by hydrogen bonds and π–π stacking to from a three-dimensional supramolecular framework. This behaviour was confirmed by Hirshfeld surface analysis. The thermal analysis reveals that complex 1 is thermally stable up to 160 °C. The magnetic measurements indicated the diamagnetic nature of this CuI coordination polymer.