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Photocatalytic CO2 reduction is one of the best solutions to solve the global energy crisis and to realize carbon neutralization. The tetradentate phosphine‐bipyridine (bpy)‐phosphine (PNNP)‐type Ir(III) photocatalyst, Mes‐IrPCY2, was reported with a high HCOOH selectivity but the photocatalytic mechanism remains elusive. Herein, we employ electronic structure methods in combination with radiative, nonradiative, and electron transfer rate calculations, to explore the entire photocatalytic cycle to either HCOOH or CO, based on which a new mechanistic scenario is proposed. The catalytic reduction reaction starts from the generation of the precursor metal‐to‐ligand charge transfer (3MLCT) state. Subsequently, the divergence happens from the 3MLCT state, the single electron transfer (SET) and deprotonation process lead to the formation of one‐electron‐reduced species and Ir(I) species, which initiate the reduction reaction to HCOOH and CO, respectively. Interestingly, the efficient occurrence of proton or electron transfer reduces barriers of critical steps. In addition, nonadiabatic transitions play a nonnegligible role in the cycle. We suggest a lower free‐energy barrier in the reaction‐limiting step and the very efficient SET in 3MLCT are cooperatively responsible for a high HCOOH selectivity. The gained mechanistic insights could help chemists to understand, regulate, and design photocatalytic CO2 reduction reaction of similar function‐integrated molecular photocatalyst. [ABSTRACT FROM AUTHOR]

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]

We here disclose that the incorporation of thiophene rings into a seven‐membered 8π azepine in a fused fashion produces a useful antiaromatic core for near‐infrared (NIR) dyes. In contrast to dibenzazepine derivatives with bent structures, dithieno‐fused derivatives with electron‐accepting groups adopt flat conformations in the ground state. The dithieno‐fused derivatives exhibited broad absorption spectra that cover the visible region as well as sharp emission bands in the NIR region, which are considerably red‐shifted relative to those of the dibenzo‐fused congeners. Theoretical study revealed two contradictory effects of the less‐aromatic thiophene‐fused structure, i.e. the enhancement of the antiaromaticity of the adjacent azepine ring and the relief of the antiaromaticity through the contribution of a quinoidal resonance form. The combination of the dithienoazepine core with cationic electron‐accepting groups produced a NIR fluorescent dye with an emission at 878 nm in solution. [ABSTRACT FROM AUTHOR]

The photo‐responsive adsorption has emerged as a vibrant area, but its current methodology is limited by the well‐defined photochromic units and their molecular deformation driven by photo‐stimuli. Herein, a methodology of nondeforming photo‐responsiveness is successfully exploited. With the exploiting agent of Cu‐TCPP framework assembled on the graphite and strongly interacted with it, the sorbent generates two kinds of adsorption sites, over which the electron density distribution of the graphite layer can be modulated at the c‐axis direction, which can further evolve due to photo‐stimulated excited states. The excited states are stable enough to meet the timescale of microscopic adsorption equilibrium. Independent of the ultra‐low specific surface area of the sorbent (20 m2 g−1), the CO adsorption capability can be improved from 0.50 mmol g−1 at the ground state to 1.24 mmol g−1 (0 °C, 1 bar) with the visible light radiation, rather than the photothermal desorption. [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]

Pressure‐induced emission (PIE) associated with self‐trapping excitons (STEs) in low‐dimensional halide perovskites has attracted great attention for better materials‐by‐design. Here, using 2D layered double perovskite (C6H5CH2CH2NH3+)4AgBiBr8 as a model system, we advance a fundamental physicochemical mechanism of the PIE from the perspective of carrier dynamics and excited‐state behaviors of local lattice distortion. We observed a pressure‐driven STE transformation from dark to bright states, corresponding a strong broadband Stokes‐shifted emission. Further theoretical analysis demonstrated that the suppressed lattice distortion and enhanced electronic dimensionality in the excited‐state play an important role in the formation of stabilized bright STEs, which could manipulate the self‐trapping energy and lattice deformation energy to form an energy barrier between the potential energy curves of ground‐ and excited‐state, and enhance the electron‐hole orbital overlap, respectively. [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]

Fungal infections caused by Candida species are among the most prevalent in hospitalized patients. However, current methods for the detection of Candida fungal cells in clinical samples rely on time‐consuming assays that hamper rapid and reliable diagnosis. Herein, we describe the rational development of new Phe‐BODIPY amino acids as small fluorogenic building blocks and their application to generate fluorescent antimicrobial peptides for rapid labelling of Candida cells in urine. We have used computational methods to analyse the fluorogenic behaviour of BODIPY‐substituted aromatic amino acids and performed bioactivity and confocal microscopy experiments in different strains to confirm the utility and versatility of peptides incorporating Phe‐BODIPYs. Finally, we have designed a simple and sensitive fluorescence‐based assay for the detection of Candida albicans in human urine samples. [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]