Tunability in dimension, metal and ligand coordination modes and emission properties in Cd(II) and Zn(II) coordination networks based on 4,4’-(hydrazine-1,2-diyilidenebis(methanylylidene)) dibenzoic acid linker

Abstract

Cd(II) and Zn(II) coordination polymers based on dicarboxylic azine chromophore, 4,4'-(hydrazine-1,2-diylidenebis(methanylylidene)) dibenzoic acid (H2(4-dbahz)), were obtained and include 1D coordination polymer {[Cd(4-dbahz)(dmso)2(H2O)]·(dmso)2}n (1, 2) in the forms of monoclinic and orthorhombic polymorphs, 2D coordination grid {[Zn(4-dbahz)(dmso)]·0.5(dmso·dmf)}n (3), and 3D MOF {[Cd2(4-dbahz)2(dmso)2]·dmso}n (4). The coordination compounds and H2(4-dbahz) chromophore were studied using spectroscopic (FTIR, NMR, PL) and X-ray diffraction methods of analysis. The organic chromophore H2(4-dbahz) reveals dual emission indicated by the emission bands in the high and low energy regions of spectrum. The tuning of emission properties was followed for the as-synthesized coordination polymers 1, 3, 4 and their desolvated products and showed excellent sensing of solvated dmso. The significant enhancement of photoluminescence in the blue region in 1 is associated with elimination of π-π stacking interactions due to accommodation of dmso solvent.