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Two copper (II) complexes based on the mixed ligand system were synthesized and structurally characterized. The molecular formulae for complex (1), [Cu2L1L′] and complex (2), [CuL2L′] were determined based on analytical data, molar conductance, and thermal analysis results. The optimized structures of complexes (1) and (2) were determined by magnetic and spectroscopic measurements (FTIR, UV–Vis, and ESR) and confirmed by processing powder X‐ray diffraction data by Expo 2014 software. The geometry index (τ5), determined by ESR spectra and structural analysis based on powder X‐ray, demonstrates the square pyramidal geometry of the Cu (II) center of [Cu2L1L′] and [CuL2L′]. Cyclic voltammetry measurements were performed to elucidate the relationship between the redox properties of (1) and (2) and their oxidase‐mimicking catalytic activity. Catalytic aerobic oxidation of the polyphenols 3,5‐di‐tert‐butylcatechol (3,5‐DTBCH2), 4‐nitrocatechol, and 2‐aminophenol (2‐APH3) was studied by stopped‐flow technique. Promising catechol oxidase (COX) and phenoxazinone synthase (PHS) mimetic activity have been demonstrated for (1) and (2). Electrochemical data were used to determine the free energy (ΔG°) or driving force (−λ), and their correlation with the oxidase mimetic activity of(1) and (2) was examined. Several experimental procedures have been performed that have helped describe the catalytic mechanisms of the catalytic reactions taking place. [ABSTRACT FROM AUTHOR]

As the removal of toxic dyes by catalytic degradation is interestingly growing field, diverse types of nanomaterials are used intensively as a catalyst to enhance the catalytic degradation of toxic dyes in the last decades. The unique property of ionic crosslinking of the biopolymer sodium alginate (Na‐ALG) in presence of CaCl2 solution is exploited to prepare Ca‐alginate (Ca‐ALG) microbeads, which further used as precursor for in situ silver nanoparticles (Ag NPs) formation by the effect of gamma radiation to obtain Ca‐ALG/Ag nanocomposite beads. The amount of silver ions adsorbed by the Ca‐ALG beads before reduction was evaluated by using ultraviolet‐visible spectrophotometer (UV–Vis). The physicochemical properties of prepared Ca‐ALG/Ag nanocomposite beads were studied by various techniques as X‐ray diffraction (XRD) and transmission electron microscopy (TEM) for approving the creation of Ag NPs and assessing its morphology and particle magnitude. The catalytic reduction ability of the resulting Ca‐ALG/Ag nanocomposite beads is studied toward the degradation of basic blue 3 dye as a model anionic dye by the aid of the reducing agent NaBH4 under various factors including time, pH, catalyst's dosage, NaBH4 contents, and dye's initial concentration. Various kinetics and isothermal models were applied for forecasting the mechanism of the degradation process using the prepared catalyst beads. The kinetics and isothermal study revealed that the degradation process using Ca‐LG/Ag nanocomposite beads as a catalyst in presence of NaBH4 as a reducing agent was best fit the pseudo‐second‐order model and Langmuir isotherm model. [ABSTRACT FROM AUTHOR]