Photoinduced atom transfer radical polymerization (photo-ATRP) has risen to the forefront of modern polymer chemistry as a powerful tool giving access to well-defined materials with complex architecture. However, most photo-ATRP systems can only generate radicals under biocidal UV light and are oxygen-sensitive, hindering their practical use in the synthesis of polymer biohybrids. Herein, inspired by the photoinduced electron transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization, we demonstrate a dual photoredox/copper catalysis that allows open-air ATRP under green light irradiation. Eosin Y was used as an organic photoredox catalyst (PC) in combination with a copper complex (X–Cu^II/L). The role of PC was to trigger and drive the polymerization, while X–Cu^II/L acted as a deactivator, providing a well-controlled polymerization. The excited PC was oxidatively quenched by X–Cu^II/L, generating Cu^I/L activator and PC˙⁺. The ATRP ligand (L) used in excess then reduced the PC˙⁺, closing the photocatalytic cycle. The continuous reduction of X–Cu^II/L back to Cu^I/L by excited PC provided high oxygen tolerance. As a result, a well-controlled and rapid ATRP could proceed even in an open vessel despite continuous oxygen diffusion. This method allowed the synthesis of polymers with narrow molecular weight distributions and controlled molecular weights using Cu catalyst and PC at ppm levels in both aqueous and organic media. A detailed comparison of photo-ATRP with PET-RAFT polymerization revealed the superiority of dual photoredox/copper catalysis under biologically relevant conditions. The kinetic studies and fluorescence measurements indicated that in the absence of the X–Cu^II/L complex, green light irradiation caused faster photobleaching of eosin Y, leading to inhibition of PET-RAFT polymerization. Importantly, PET-RAFT polymerizations showed significantly higher dispersity values (1.14 ≤ Đ ≤ 4.01) in contrast to photo-ATRP (1.15 ≤ Đ ≤ 1.22) under identical conditions.

High-pressure conditions can be considered as an alternative, environmentally responsible way for the equilibrium reactions, such as disulfide exchange. This approach is capable of eliminating the catalysts or stimuli, such as reducing agents, strong bases, ultraviolet light, or ultrasound. The exchange of aryl disulfides in the absence of catalysts or other stimuli has been systematically studied. The effects of pressure in the range between 100 and 400 MPa, accessible in large-scale technological installations, have been tested for promoting exchange reactions between various homodimeric aryl disulfides. For the optimized conditions, 100% yields of the heterodimer in pure single-crystal form were obtained. The reactions were performed in a diamond anvil cell, as well as in a hydraulic piston-and-cylinder press, and the products were characterized by X-ray diffraction, mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy. The prominent role of high-entropy states, not attainable under ambient conditions, as well as the high-entropy nucleation, kinetic crystallization, and other effects associated with the high-pressure environment, has been demonstrated. These entropy-driven reactions represent an efficient, environmentally friendly, one-pot method for obtaining pure crystalline heterodimeric disulfides.

Porous 1,2-bis[2-methyl-5-(pyridyl)-3thienyl] cyclopentene cocrystal with 1,4-diiodotetrafluorobenzene exhibits large negative linear compression correlated with the shape of pores.

Mechanical and thermal strains in organic photovoltaic layers deposited on poly(ethylene terephthalate) (PET) and glass substrates and the resulting effect on the bandgap energy have been determined for the organic charge-transfer polymer PTB7. Its strong bathochromic shift of the absorption spectra under pressure also depends on the layer preparation method. The effects of different solvents and PTB7 concentrations on agglomerate formation were also studied. A perfect linear dependence of the concentration vs. absorbance was observed up to 1.81 × 10⁻⁷ M for chlorobenzene or o-dichlorobenzene solution. The thermal image monitoring of the current response at an increasing potential showed a linear current-to-voltage tendency, indicating that the conductive behaviour of the polymer depends on the substrate used in PET/ITO/PTB7/Ag/ITO/PET and glass/ITO/PTB7/Ag/ITO/glass devices. The PTB7 layer on the PET/ITO substrate displays superior mechanical properties suitable for flexible photovoltaic panels exposed to strain and deformations.