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Aryl‐maleimides undergo a novel [2+4]‐photodimerization instead of the expected [2+2]‐photodimerization under both direct irradiation with visible light and under sensitized energy transfer conditions. This new excited state reactivity in aryl‐maleimides is deciphered through photochemical, photophysical, and spectroscopic studies. The stereochemistry of the photodimer depends on the type of non‐bonding interactions prevalent during photodimerization which is in turn dictated by the substituents on the maleimide ring. More importantly, the stereochemistry of the photodimer formed is complementary to the product observed under thermal conditions. [ABSTRACT FROM AUTHOR]

Donor–π–acceptor fluorophores that consist of an electron‐donating amino group and an electron‐accepting triarylborane moiety generally exhibit substantial solvatochromism in their fluorescence while retaining high fluorescence quantum yields even in polar media. Herein, we report a new family of this compound class, which bears ortho‐P(=X)R2‐substituted phenyl groups (X=O or S) as a photodissociative module. The P=X moiety that intramolecularly coordinates to the boron atom undergoes dissociation in the excited state, giving rise to dual emission from the corresponding tetra‐ and tricoordinate boron species. The susceptibility of the systems to photodissociation depends on the coordination ability of the P=O and P=S moieties, whereby the latter facilitates dissociation. The intensity ratios of the dual emission bands are sensitive to environmental parameters, including temperature, solution polarity, and the viscosity of the medium. Moreover, precise tuning of the P(=X)R2 group and the electron‐donating amino moiety led to single‐molecule white emission in solution. [ABSTRACT FROM AUTHOR]

Photosensitization associated with electron/energy transfer represents the central science of natural photosynthesis. Herein, we proposed a protocol to dramatically improve the sensitizing ability of metal–organic frameworks (MOFs) by switching their excited state distribution from 3MLCT (metal‐to‐ligand charge transfer) to 3IL (intraligand). The hierarchical organization of 3IL MOFs and Co/Cu catalysts facilitates electron transfer for efficient photocatalytic H2 evolution with a yield of 26 844.6 μmol g−1 and CO2 photoreduction with a record HCOOH yield of 4807.6 μmol g−1 among all the MOF photocatalysts. Systematic investigations demonstrate that strong visible‐light‐absorption, long‐lived excited state and ingenious multi‐component synergy in the 3IL MOFs can facilitate both interface and intra‐framework electron transfer to boost photocatalysis. This work opens up an avenue to boost solar‐energy conversion by engineering sensitizing centers at a molecular level. [ABSTRACT FROM AUTHOR]

This article, titled "Inside Cover: Dithienoazepine-Based Near-Infrared Dyes: Janus-Faced Effects of a Thiophene-Fused Structure on Antiaromatic Azepines," discusses a design strategy for creating near-infrared (NIR) dyes using antiaromatic azepine. The authors, Masahito Murai, Takahiro Enoki, and Shigehiro Yamaguchi, explain that while benzo-fused azepines have bent conformations that become planar in the excited state, thieno-fused azepines with electron-accepting groups remain flat even in the ground state, resulting in NIR emissions beyond 850 nm. The article includes cover art by Dr. Issey Takahashi at ITbM, Nagoya University. [Extracted from the article]

Keywords: Boron; Donor-Acceptor Systems; Excited State; Fluorescence; Stimulus-Responsiveness EN Boron Donor-Acceptor Systems Excited State Fluorescence Stimulus-Responsiveness 1 1 1 06/20/23 20230626 NES 230626 B Dual-emissive b triarylborane-based donor- -acceptor fluorophores sensitive to environmental parameters, including temperature, solvent polarity, and viscosity of the medium, are reported by Shigehiro Yamaguchi and co-workers in their Research Article (e202303725). Boron, Donor-Acceptor Systems, Excited State, Fluorescence, Stimulus-Responsiveness Back Cover: Photodissociative Modules that Control Dual-Emission Properties in Donor- -Acceptor Organoborane Fluorophores (Angew. [Extracted from the article]