Sorption and sensing properties of coordination polymers with mixed 1,3,5-tri(1-imidazolyl)benzene and 2,6-naphthalenedicarboxylate ligands

Under hydro/solvothermal conditions, the assembly of imidazole-containing ligand 1,3,5-tri(1-imidazolyl)benzene (tib) and 2,6-naphthalenedicarboxylic acid (H 2 NDC) with different transition metal salts provides five new coordination polymers [M 2 (tib) 2 (NDC)(H 2 O) 2 ] SO 4 · X H 2 O ( 1 : M = Cd, X = 4; 2 : M = Co, X = 4; 3 : M = Ni, X = 3), [Cd 2 (tib) 2 (NDC)(NO 3 ) 2 ] 2.5DMF·H 2 O ( 4 ) (DMF = N , N -dimethylformamide) and [Zn(tib) 2/3 (NDC)] ( 5 ). 1–3 have the same three-fold interpenetrating 3D framework structures with SO 4 2− as counteranion, while 4 with NO 3 − as terminal ligand exhibits a wave-like 2D layer structure, which is further extended into a 3D framework by hydrogen bonds. In addition, complex 5 obtained at high temperature is an interesting two-fold interpenetrating 3D structure. Sorption and photoluminescence properties of the complexes were investigated. 4 displays selective adsorption of CO 2 over N 2 . Furthermore, 1 and 4 can be used to probe acetone molecules selectively and rapidly via fluorescence quenching.