The role of nitrogen doping in the highly efficient oxygen photosensitization of carbon dots is underlined.

For the first time, UiO-66(Ce) was endowed with greatly improved redox photocatalytic activity via Ti incorporation, based on the formation of oxygen vacancies.

Light-driven carbon dioxide (CO 2 ) capture and utilization is one of the most fundamental reactions in Nature. Herein, we report the first visible-light-driven photocatalyst-free hydrocarboxylation of alkenes with CO 2 . Diverse acrylates and styrenes, including challenging tri-and tetrasubstituted ones, undergo anti-Markovnikov hydrocarboxylation with high selectivities to generate valuable succinic acid derivatives and 3-arylpropionic acids. In addition to the use of stoichiometric aryl thiols, the thiol catalysis is also developed, representing the first visible-lightdriven organocatalytic hydrocarboxylation of alkenes with CO 2 . The UV-vis measurements, NMR analyses, and computational investigations support the formation of a novel charge-transfer complex (CTC) between thiolate and acrylate/styrene. Further mechanistic studies and density functional theory (DFT) calculations indicate that both alkene and CO 2 radical anions might be generated, illustrating the unusual selectivities and providing a novel strategy for CO 2 utilization.

Electron spin–lattice relaxation of two trityl radicals, d24-OX063 and Finland trityl, were studied under conditions relevant to their use in dissolution dynamic nuclear polarization (DNP). The dependence of relaxation kinetics on temperature up to 100 K and on concentration up to 60 mM was obtained at X- and W-bands (0.35 and 3.5 Tesla, respectively). The relaxation is quite similar at both bands and for both trityl radicals. At concentrations typical for DNP, relaxation is mediated by excitation transfer and spin-diffusion to fast-relaxing centers identified as triads of trityl radicals that spontaneously form in the frozen samples. These centers relax by an Orbach–Aminov mechanism and determine the relaxation, saturation and electron spin dynamics during DNP.

Herein, we report a discovery that photochemical vapor generation (PCVG) of molybdenum (Mo) can be synergistically enhanced dramatically by cobalt and copper ions sourced from acetates in the medium of formic acid, utilizing a flow-through reactor. The nature of this new PCVG was probed for the first time by an electron paramagnetic resonance (EPR) spin trapping technique for its possible reaction mechanism. Carboxyl and hydroxyl free radicals were verified during PCVG processes, and the results indicate that variations in the relative amounts and proportions of free radical species may account for the synergistic effect from concomitant Co2+ and Cu2+, as well as the generation of molybdenum hexacarbonyl from the UV-induced photolysis of formic acid. Under “dry” plasma conditions, the simultaneous spiking of Co2+ and Cu2+ to 20% (v/v) formic acid solutions and a 60 s irradiation time could give rise to a 15-fold enhancement in signal intensities, together with a blank-limited but still impressive limit of detection of 6 ng L–1 (6 ppt) by inductively coupled plasma mass spectrometry (ICP-MS). The accuracy and reliability of this methodology was validated by analysis of molybdenum in a seawater certified reference material, CASS-6, as well as two varieties of drinking water and seawater samples, with satisfactory spike recoveries (91–101%).

Cobalt ion-assisted enhancement of photochemical vapor generation in a mixed acid medium was used for sensitive determination of tellurium(iv) by atomic fluorescence spectrometry.

Nitrogen analogues of Chichibabin's and Müller's hydrocarbons exhibit small singlet–triplet energy gaps (ΔES–T from −1.05 to −1.27 kcal mol−1).

Heteroatoms were introduced as a novel modification strategy for fine-tuning the diradical character of molecular systems.