Syntheses, crystal structures, dye degradation and luminescence sensing properties of four coordination polymers

Abstract

Four coordination polymers, namely, {[Co(cpnc)(bpbenz)]}_n (1), {[Co(cpnc)(bide)₂]}_n (2), {[Co(cpnc)(bide) (H₂O)_1/2]·H₂O}_n (3), and {[Cd(cpnc)(bib)_1/2(H₂O)₂]}_n (4) (H₂cpnc = 6-(4-carboxyphenyl)nicotinic acid, bpbenz = 1,4-bis(4-pyridyl)benzene, bide = 4,4′-bis(imidazolyl)diphenyl ether, and bib = 1,4-bis(1-imidazoly)benzene) have been solvothermally synthesized and characterized by powder X-ray diffraction, elemental analysis, and infrared spectroscopy. Structural analysis reveals that compound 1 consists of a 3D 3-fold interpenetrated framework with pcu topology. Compounds 2 and 3 have been synthesized by one-pot reactions. Compound 2 comprises 2D layers, while compound 3 comprises 1D chains. Compound 4 consists of 2D layers constructed from mixed ligands. In addition, the photocatalytic activities of 1–3 under UV light toward methyl orange (MO), rhodamine B (RB), methyl blue (MB), neutral red (NR), methylene blue (MEB), and safranine T (ST) with H₂O₂ are investigated in aqueous solutions. The results suggested that the photocatalytic efficiency of 1 for MO was 100% in one hour and that of 2 for ST was 90% in two hours; furthermore, the photocatalytic efficiencies of 3 for MO and ST were found to be 100% and 92% in one hour, respectively. The photoluminescence titration experiments demonstrate that 4 is an excellent multifunctional probe for metal ions (Fe³⁺ and Cu²⁺) and anions (Cr₂O₇²⁻ and CO₃²⁻).