Recent advances in photocatalytic polyfluoroarylation.

Polyfluoroaryl compounds belong to privileged moieties and engender distinct properties in many pharmaceuticals, agrochemicals, and materials. Over the past decade, considerable seminal reports and reviews have merely paid close attention to fluoroalkylation chemistry, such as trifluoromethylation, difluoroalkylation, perfluoroalkylation, trifluoromethylthiolation or trifluoromethoxylation. Polyfluoroarylation has inevitably lagged somewhat behind its fluoroalkylation counterparts, emanating from a lack of awareness and understanding of the synthetic significance. Together with the renaissance of photochemistry, the photocatalytic polyfluoroarylation using polyfluoroarenes as an inexpensive and easy-available radical precursor has emerged as a topical interest and vibrant area of chemical research. In this review, we have endeavored to present the state-of-the-art in photocatalytic polyfluoroarylation since 2014, and the discussions cover the basic concept, reaction design, mechanistic insight, and research prospects, which are organized by the reaction types. We hope this review will provide a comprehensive overview of this topic and stimulate significant research interest.

All-solid-state bipolar pulsed generator based on linear transformer driver and push-pull circuit.

All-solid-state linear transformer drivers (LTDs) are widely used in high-voltage repetitive nanosecond-pulsed generators, and only a few LTD generators can output bipolar rectangular waves currently. Furthermore, owing to the large reverse overshoot when the output pulse width is long, fewer LTD generators can achieve a rectangular wave output with a microsecond pulse width. In this study, a bipolar LTD circuit topology based on a push-pull circuit is proposed for irreversible electroporation. In this topology, a single-stage LTD module has four push-pull branches in its primary winding to achieve a bipolar output and a short-circuited winding with two resistor-capacitor-diode snubbers to suppress forward/reverse overshoot. A single-stage LTD module and a 12-stage LTD have been tested, and the results show that they can output bipolar rectangular pulses with variable parameters. When the output pulse width is 100 ns to 1 µs, the maximum output voltage amplitude is 5.74 kV, the rise time is 29.1 ns, and the reverse overshoot at 1 µs is 2.9%. When the output pulse width is 1-8 µs, the maximum output voltage amplitude is 2.93 kV, the rise time is 24.3 ns, and the reverse overshoot at 8 µs is 11.3%.

Recent advances of 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) in photocatalytic transformations.

1,2,3,5-Tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) is a typical donor-acceptor fluorophore, with carbazolyl as an electron donor and dicyanobenzene as an electron acceptor. It has emerged as a powerful organophotocatalyst since 2016. Excellent redox window, good chemical stability and broad applicability make 4CzIPN an attractive metal-free photocatalyst. In this review, the recent advances of the application of 4CzIPN as a photoredox catalyst in the past three years (2016-2018) for various organic reactions are summarized.

Construction of an ultrasensitive non-enzymatic sensor to investigate the dynamic process of superoxide anion release from living cells.

In this work, a novel non-enzymatic superoxide anion (O2•-) sensor was constructed based on Ag nanoparticles (NPs) / poly (amidoamine) (PAMAM) dendrimers and used to investigate the dynamic process of O2•- release from living cells. The AgNPs/PAMAM nanohybrids were characterized by transmission electron microscopy (TEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The fabricated electrode exhibited excellent catalytic activity toward the reaction of O2•- with a super low detection limit (LOD) of 2.530 × 10-13M (S/N = 3) and wide linear range of 8 orders of magnitude. It could fulfill the requirement of real-time measurement O2•- released from living cells. Furthermore, zymosan was chosen as the stimulant to induce O2•- generation from cancer cells (rat adrenal medulla pheochromocytoma cell (PC12)). The electrochemical experiment results indicated that the levels of intracellular O2•- depended on the amount of Zymosan. A large amount of O2•- generated in the living cells by added heavy stimulant could damage cells seriously. More importantly, a vitro simulation experiment confirmed the role of superoxide dismutase (SOD) for the first time because it could maintain the O2•- concentration at a normal physiological range. These findings are of great significance for evaluating the metabolic processes of O2•- in the biological system, and this work has the tremendous potential application in clinical diagnostics to assess oxidative stress.