Syntheses, characterizations and photochromic properties of 1D→2D polycatenated cationic coordination polymers based on the flexible tripodal zwitterionic ligand

Two new coordination compounds, namely, {[ZnBr(mu 3-tazna)]NO3.4H2O}n 3-tazna)]NO 3 .4H 2 O} n (1) 1 ) and {[CdBr(mu 3-tazna)] 3-tazna)] ClO4.2H2O}n 4 .2H 2 O} n (2) 2 ) were solvothermally synthesized from the 1,1 ',1 ''-(((1,3,5-triazin-2,4,6-triyl)tris(benzene-4,1- ' ,1 ''-(((1,3,5-triazin-2,4,6-triyl)tris(benzene-4,1- diyl))tris(methylene))tris(3-carboxypyridin-1-ium) bromide (H3taznaBr3) 3 taznaBr 3 ) ligand and characterized by IR spectroscopy, elemental analysis, X-ray single-crystal diffraction, X-ray powder diffraction (PXRD), and thermal analyses techniques. Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 crystallize in the triclinic system, P-1 space group. In 1 and 2 , Zn(II) and Cd(II) centers are bridged by tazna ligands, displaying a rare 1D -> 2D structure formed by the catenation of a 1D double chain. The photochromic behavior of compound 2 was investigated under 365 nm UV light, exhibiting a color change from white to yellow. Furthermore, the thermal and optical absorption properties of compounds 1 and 2 were investigated.