Diarylmaleic anhydride derivatives containing benzene (BPMA), thiophene (BTMA) and indole (BIMA) exhibit diverse and distinct fluorescence: aggregation-caused quenching (ACQ) of red emission of BIMA, blue aggregation-induced emission (AIE) of BPMA, and green dual-state emission (DSE) of BTMA in both solution and the solid state. Theoretical calculation and crystal structure analysis indicate that intramolecular and intermolecular interactions are responsible for their different emission behavior. A series of DSE-active molecules with full-color emission could be developed for the first time, through modification of the structures of BPMA and BIMA. Interestingly, BTMA and BPMA display multi-stimuli-responsive luminescence with a high-contrast (Δλ_em > 100 nm) and an unusual photochromic phenomenon in dichloromethane, which were utilized to construct rewritable data storage and mimic molecular logic operation (4-to-2 encoder and 1 : 2 demultiplexer), respectively.

A low-cost, hyper-branched, carbazole-based polymer (HB-Cz) was designed and synthesized by a facile “A3 + B2” one-pot Suzuki polycondensation reaction. Due to the hyper-branched structure and carbazole unit, HB-Cz is a promising candidate for a hole-transporting material, which was confirmed in perovskite solar cells (PVSCs) with a configuration of ITO/TiO₂/MAPbI₃/HB-Cz/Ag. The films of poly-(3-hexylthiophene) and linear poly[N-(1-octylnonyl)-9H-carbazole-2,7-diyl] were also used as hole-transporting layers (HTLs) in the reference devices. Time-resolved photoluminescence spectra indicate that HB-Cz has the fastest charge regeneration. Electrochemical impedance spectroscopy revealed that HB-Cz could reduce carrier recombination effectively, improving the open circuit voltage and fill factor of the PVSCs. A PCE of 14.07% obtained from the HB-Cz-based device was much higher than those of devices based on P3HT (9.05%) and PCz (6.60%), and this is attributed to the superior hole-transporting property and surface smoothing effect of the HB-Cz HTL.

The radical TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl radical) and its derivatives are well-established catalysts for oxidation processes, and now used extensively in organic synthesis and industrial applications as a mild, safe, and economical alternative to heavy metal reagents as highly selective oxidation catalysts. In this review, we attempt to fully review the recent advances in the syntheses of TEMPO and its derivatives as well as their applications in recent years. The synthesis of TEMPO and its derivatives are discussed first. The largest section focuses on their application as stoichiometric and catalytic oxidants in organic synthesis, particularly focusing on the formation of C-C, C-O, C=O, C-N, and C=N bond. Simultaneously, the oxidation of alcohols to their corresponding carbonyl compounds also is commented briefly. The last section discusses the application of the TEMPO-catalyzed reactions in the total syntheses of natural products.