Developing novel technologies to cleanup wastewater has attracted attention for a long while in academic and industrial communities not only for environmental issues but also for recycling water sources. This work demonstrates that bicarbonate-activated H2O2 can be applied as a novel oxidant source in pollutant degradation. Using a supported cobalt catalyst, bicarbonate-activated H2O2 can efficiently degrade various dyes and phenol at ambient temperature. Because the reaction media remains weakly basic during degradation, the cobalt leaching from the solid catalyst has been efficiently avoided and the lifetime of the catalyst can be extended to above 180 h without significant activity loss in a fixed-bed test. Different scavengers, including ascorbic acid, t-butanol, sodium azide, benzoquinone, and tiron, have been tested to identify the active species, which may be involved in pollutant degradation, and it was found that singlet oxygen and the carbonate radical may play a key role in the degradation process.

Iridium complexes are drawing great interest because they exhibit high phosphorescence quantum efficiency. Extensive efforts have been devoted to the molecular design of ligands to achieve phosphorescent emission over a wide range of wavelengths that is compatible with many applications. In this research news article, we focus on materials design to improve the performance of phosphorescent Ir(III) complexes for organic light-emitting diodes (OLEDs), luminescence sensitizers, and biological imaging.

Nonradical-based advanced oxidation processes for pollutant removal have attracted much attention due to their inherent advantages. Herein we report that magnesium oxides (MgO) in CuOMgO/Fe3O4 not only enhanced the catalytic properties but also switched the free radical peroxymonosulfate (PMS)-activated process into the 1O2 based nonradical process. CuOMgO/Fe3O4 catalyst exhibited consistent performance in a wide pH range from 5.0 to 10.0, and the degradation kinetics were not inhibited by the common free radical scavengers, anions, or natural organic matter. Quantitative structure–activity relationships (QSARs) revealed the relationship between the degradation rate constant of 14 substituted phenols and their conventional descriptor variables (i.e., Hammett constants σ, σ–, σ+), half-wave oxidation potential (E 1/2), and pK a values. QSARs together with the kinetic isotopic effect (KIE) recognized the electron transfer as the dominant oxidation process. Characterizations and DFT calculation indicated that the incorporated MgO alters the copper sites to highly oxidized metal centers, offering a more suitable platform for PMS to generate metastable copper intermediates. These highly oxidized metals centers of copper played the key role in producing O2 •– after accepting an electron from another PMS molecule, and finally 1O2 as sole reactive species was generated from the direct oxidation of O2 •– through thermodynamically feasible reactions.

Using heteropolyacid and copper(ii) as catalysts, renewable furfural has been successfully transformed to maleic anhydride and biologically important 5-acetoxyl-2(5H)-furfuran.

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Developing novel technologies to utilize renewable biomass as the source of energy and carbon to partially replace the fossil resources has been well recognized by the global governments and both industrial and academic communities. This work explored a catalytic transformation of biomass-based 5hydroxymethylfurfural to maleic anhydride and maleic acid through aerobic oxidation with vanadium-substituted heteropolyacid. Under the optimized conditions, total yields of 64% for maleic anhydride and maleic acid could be achieved. Mechanistic studies with control experiments excluded 2, 5-furandicarboxylic acid, 2, 5-diformylfuran, 5-formyl-2-furancarboxylic acid, and 5hydroxymethyl-2-furancarboxylic acid as the intermediates in the pathway of 5-hydroxymethylfurfural oxidation to maleic anhydride. Alternatively, a new mechanism initialized by the C−C bond cleavage between the hydroxymethyl group and furan sketch of HMF by heteropolyacid has been proposed for MA formation, in which several intermediates have been identified through GC-MS analysis.

While the significance of the redox metal oxo moieties has been fully acknowledged in versatile oxidation processes, active metal hydroxo moieties are gradually realized to play the key roles in certain biological oxidation events, and their reactivity has also been evidenced by related biomimic models. However, compared with the metal oxo moieties, the significance of the metal hydroxo moieties has not been fully recognized, and their relationships in oxidations remain elusive until recently. This review summarizes the reactivity of the metal oxo and hydroxo moieties in different oxidation processes including hydrogen atom transfer, oxygen atom transfer and electron transfer, and their reactivity similarities and differences have been discussed as well. Particularly, how the physicochemical properties like metal-oxygen bond order, net charge and potential of a redox metal ion affect its reactivity has also been presented based on available data. We hope that this review may provide new clues to understand the origins of the enzyme's choice on them in a specific event, to explain the elusive phenomena occurring in those enzymatic, homogeneous and heterogeneous oxidations, to design selective redox catalysts and control their reactivity.

Two novel iridium-europium bimetallic complexes, {[(dfppy)2Ir(mu-phen5f)]3EuCl}Cl2 and (dfppy)2Ir(mu-phen5f)Eu(TFAcA)3 [dfppy represents 2-(4',6'-difluorophenyl)-pyridinato-N,C(2'), phen5f stands for 4,4,5,5,5-pentafluoro-1-(1',10'-phenanthrolin-2'-yl)-pentane-1,3-dionate and TFAcA represents trifluoroacetylacetonate], were successfully synthesized. The novel ligand Hphen5f with four coordination sites was designed as a bridge to link the Ir (III) center and the Eu (III) center. The X-ray diffraction data shows that the nonbonding distances for Eu...Ir are 6.028, 5.907, and 6.100 A in the bimetallic complex {[(dfppy)2Ir(mu-phen5f)]3EuCl}Cl2. Photophysical studies implied that the high efficient red luminescence from the Eu (III) ion was sensitized by the (3)MLCT (metal-to-ligand charge transfer) energy based on an Ir (III) complex-ligand in a d-f bimetallic assembly. The excitation window for the new bimetallic complex {[(dfppy)2Ir(mu-phen5f)]3EuCl}Cl2 extends up to 530 nm (1 x 10(-3) M in EtOH), indicating that this bimetallic complex can emit red light under the irradiation of sunlight.