Synthesis, structure and phenoxazinone synthase-like activity of three unprecedented alternating Co^II–Co^III 1D chains

Abstract

Three new one-dimensional CoII/CoIII chains have been synthesized using N-salicylidene-l-alanine/N-salicylidene-l-phenylalanine and 2,2′-bipyridine/1,10-phenanthroline. All three complexes exhibit phenoxazinone synthase-like activity.

Modulation of Nuclearity in CuII−MnII Complexes of a N2O2 Donor Ligand Depending upon Carboxylate Anions: Structures, Magnetic Properties and Catalytic Oxidase Activities

“…Phenoxazinone synthase‐like activity : During the catalysis reaction by complexes ( 1–3 ), we have checked by iodometric method that no H 2 O 2 is formed as by‐product, so, water is produced rather as a side product. The investigation on mechanism of this catalysis using some reported homo‐metallic Cu II , Co II/III , and Mn II/III complexes is clearly indicative of radical mechanism with formation of aminophenolate intermediate in presence of areal oxygen [10b,28,29] …”

Synthesis, Characterization and Biomimetic Activity of Heterogenized Dioxidomolybdenum(VI) and Analogous Homogeneous Complexes

“…The phenoxazinone synthase biomimicking activity was examined by mixing 1 mL each of a methanolic solution of 1 (3.6×10 −5 m ) or 2 (3.4×10 −5 m ), OAP (1.0×10 −2 m ) in acetonitrile and H 2 O 2 (1.0×10 −2 m ) in acetonitrile. The generation of a characteristic peak of the APX chromophore at 430 nm [37,38−40] was studied by UV‐visible spectrophotometer, and its progressive increment was monitored at a frequency of 15 minutes for 5 h. Figure 18(a) presents complete profiles for catalyst 1 [Figure S10 (a) for 2 ]. No appreciable advancement of the band at 430 nm was perceived in a blank experiment, i. e., without catalyst or H 2 O 2 .…”

“…For this activity, equal volumes of metal complexes (∼ 10 À 5 M), OAP solution (10 À 2 M) and H 2 O 2 (10 À 2 M) were combined. The reaction advancement was tracked by UV-visible spectrophotometer by noticing a gradual increase at 430 nm (ε = 9095 m À 1 cm À 1 ) [37] due to phenoxazinone chromophore as a function of time. Various kinetic parameters were determined by employing multiple concentrations of the reactant with constant concentrations of the complexes and H 2 O 2 under a pseudo-firstorder reaction set-up using time-course spectral profiles.…”

Titania supported dioxidotungsten(vi) complex as bio-mimic for the type II copper-containing oxidase enzyme phenoxazinone synthase

“…A specified amount of o-aminophenol (0.011 g in 10 mL, 1.0 Â 10 À2 M) as the model substrate was treated with 30% aqueous H 2 O 2 (2.4 Â 10 À2 M) and complex 1 (6.5 Â 10 À5 M) to experience the PHS-like activity in MeOH at room temperature. The reaction progress was tracked spectrophotometrically by observing a gradual increase in the absorbance maximum at 433 nm (e = 9095 M À1 cm À1 ) 51,52 due to the formation of amino phenoxazinone as a function of time. The initial rate approach was employed to investigate the reaction kinetics of complex 1 catalysing the coupling of o-AP.…”