In situ formation of 4-cyanopyridinecarboxylic acid and its polyacid doping coordination polymer for adsorption of organic dyes in wastewater

Abstract Through adjusting the different ligands and incorporating 4, 4’-bipyridine, two novel POM-based inorganic-organic hybrid compounds {[(Cu·L1’·(4, 4’-bpy)2·2H2O)]·(β-Mo8O26)}n (1) and {[Cu·L2’·(4, 4’-bpy)]·[Cu·L2’·(β-Mo8O26)]·4H2O}n (2) [4, 4’-bpy = 4, 4’-bipyridine, L1’=1, 4-bis(pyridinio-4-carboxylato)-butane, L2’=1, 6-bis(pyridinio-4-carboxylato)-hexane] have been synthesized under different hydrothermal conditions. The two compounds were assembled by 4, 4’-bpy, CuCl2, carboxyl ligands from in-situ hydrolysis of cyano group and POM clusters, which are rarely observed in POM-based inorganic-organic hybrid compounds. Compounds 1-2 were characterized by single crystal X-ray diffraction, infrared spectrum (IR), and powder X-ray diffraction (PXRD). Compounds 1-2 have been studied for removal of organic dyes such as methylene blue (MB), methyl orange (MO) and rhodamine B (RhB).