Conjugated copper(II) porphyrin polymer and N-hydroxyphthalimide as effective catalysts for selective oxidation of cyclohexylbenzene

A-site defective La2-xCuO4 perovskite-type oxides for efficient oxidation of cyclohexylbenzene

Phenol production through the oxidation of cyclohexylbenzene (CHB) and the subsequent decomposition of tertiary hydroperoxide has attracted more and more attention. In this study, defective La2-xCuO4 perovskite-type oxide catalysts with tunable A-site deficient structures and abundant surface oxygen vacancies were developed for the liquid phase oxidation of CHB to produce cyclohexylbenzene-1-hydroperoxide (CHBHP). By tuning the amount of A-site La ions in the perovskite structure, more surface oxygen vacancies and Cu+ species were formed in catalysts. The A-site-deficient La1.9CuO4 catalyst achieved significant catalytic efficiency along with a high CHBHP yield of 27.6% at 48.6% CHB conversion under reaction conditions (i.e., 120 °C and 12 h), outperforming those of other transition metal-based catalysts previously reported in the literature. A series of structural characterization methods and catalytic reactions highlighted the crucial roles of surface oxygen vacancies and metal La and Cu ions in the oxidation process. It was revealed that metal ions favored CHB adsorption and activation, while surface oxygen vacancies facilitated the creation of active adsorbed oxygen species. The present study offers an opportunity for the future design of new high-efficiency heterogeneous catalyst systems for CHB oxidation to obtain phenol.

Structural and Spectroscopic Characterization of a Zinc-Bound N-Oxyphthalimide Radical

Thermolysis of a 1:1:1 mixture of ^MeLH (^MeL = {(2,6-ⁱPr₂C₆H₃)NC(Me)}₂CH), N-hydroxyphthalimide (HOPth), and diethylzinc in toluene at 77 °C provided [^MeLZn(OPth)] (1) in good yield after workup. The subsequent reduction of 1 with 1.3 equiv of KC₈ and 1 equiv of 2.2.2-cryptand, in tetrahydrofuran, provided [K(2.2.2-cryptand)][^MeLZn(OPth)] (2) in 74% yield after workup. Characterization of 2 via X-ray crystallography and electron paramagnetic resonance spectroscopy reveals the presence of an S = ¹/₂ radical on the N-oxyphthalimide ligand. Importantly, these data represent the first structural and spectroscopic confirmation of the redox activity of a metal-bound N-oxyphthalimide fragment, expanding the range of structurally characterized redox-active ligands.

Electrocatalytic reduction of trace nitrobenzene using a graphene-oxide@polymerized-manganese-porphyrin composite

A more stable composite of graphene oxide encapsulated by the polymerized porphyrins realize the electrocatalytic reduction of nitrobenzene to nitrosobenzene.

A sandwich-type catalytic composite reassembled with a birnessite layer and metalloporphyrin as a water oxidation catalyst

Sandwich-type MnTAPP@bir was synthesized by re-assembly of exfoliated birnessite and MnTAPP, and exhibited superior OER performance.

Porous metalloporphyrinic nanospheres constructed from metal 5,10,15,20-tetraksi(4′-ethynylphenyl)porphyrin for efficient catalytic degradation of organic dyes

Novel conjugated metalloporphyrin polymers (PP-EPMn and PX-EPMn) were synthesized by the Sonogashira coupling reaction with Mn(iii)5,10,15,20-tetraksi(4′-ethynylphenyl)porphyrin ([p-ethynyl]₄PMn) as building block, and with phenylene and xenyl groups as bridges, respectively. Fine nanospheres were obtained through control of the reaction conditions. The two polymer nanospheres were characterized in detailed by BET, FE-SEM, HR-TEM, FT-IR, UV-Vis and XPS, revealing that they were highly ordered, highly developed microporous and super-conjugated metalloporphyrin polymers with large surface areas and uniform pore sizes. Their electrochemical behaviors and hydrophilicity were also investigated. With the synergistic effects of porous nanosphere structure and conjugated covalent structure, PP-EPMn and PX-EPMn showed excellent catalytic activity and reusability in the catalytic degradation of methylene blue (3,7-bis(dimethylamino)-5-phenothiazinium chloride) in aqueous solution. The good hydrophilicity of the polymer nanospheres promoted the catalytic degradation. In particular, unlike Fenton degradation systems that require acidic conditions, PP-EPMn degraded methylene blue significantly better under alkaline conditions, which implied a good prospect in treating industrial methylene blue dye wastewater.

A kind of novel conjugated metalloporphyrin polymers were synthesized by the Sonogashira coupling reaction. They were microporous nanospherical polymers and showed excellent catalytic activities and reusability in degradation of methylene blue.