Synthesis, Structure, and Magnetic Properties of a Copper(II)‐Nitroxide Chain and Its Catalytic Activity Toward Congo Red Decolorization

A new compound [Cu(hfac) 2 (msTEMPO)] n , where hfac − is hexafluoroacetylacetonate and msTEMPO is the TEMPO derivative radical 4‐methanesulfonyl‐oxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl , was synthesized, and its magnetic behavior and catalytic activity toward the decolorization of Congo red (CR) were investigated. The crystal structure was determined by single crystal X‐ray diffraction technique, and it is described as a one‐dimensional compound with the nitroxide radical bridge‐coordinated in head‐to‐head mode to copper(II) ions. The magnetic investigation performed by magnetometry and EPR techniques revealed a TEMPO‐copper(II)‐TEMPO ferromagnetic interaction with J = +18 cm −1 . The catalytic activity was evaluated through Congo red oxidation under controlled conditions (phosphate buffer, pH = 8.5) in H 2 O 2 with the molar ratio of [Cu(hfac) 2 (msTEMPO)] n : CR: H 2 O 2 of 1: 30: X, where X = 80, 140, 200, 400, 1000, and 2000. The kinetics and rate of decolorization were obtained for all conditions where the best result for the decolorization rate was observed for the condition of 1:30:200 with 55% of decolorization ratio in 1 h against 0.5% of the uncatalyzed reaction.