Functional and evolutionary significance of unknown genes from uncultivated taxa.

Many of the Earth's microbes remain uncultured and understudied, limiting our understanding of the functional and evolutionary aspects of their genetic material, which remain largely overlooked in most metagenomic studies1. Here we analysed 149,842 environmental genomes from multiple habitats2-6 and compiled a curated catalogue of 404,085 functionally and evolutionarily significant novel (FESNov) gene families exclusive to uncultivated prokaryotic taxa. All FESNov families span multiple species, exhibit strong signals of purifying selection and qualify as new orthologous groups, thus nearly tripling the number of bacterial and archaeal gene families described to date. The FESNov catalogue is enriched in clade-specific traits, including 1,034 novel families that can distinguish entire uncultivated phyla, classes and orders, probably representing synapomorphies that facilitated their evolutionary divergence. Using genomic context analysis and structural alignments we predicted functional associations for 32.4% of FESNov families, including 4,349 high-confidence associations with important biological processes. These predictions provide a valuable hypothesis-driven framework that we used for experimental validatation of a new gene family involved in cell motility and a novel set of antimicrobial peptides. We also demonstrate that the relative abundance profiles of novel families can discriminate between environments and clinical conditions, leading to the discovery of potentially new biomarkers associated with colorectal cancer. We expect this work to enhance future metagenomics studies and expand our knowledge of the genetic repertory of uncultivated organisms.

High-level reverse intersystem crossing of charge transfer compounds: to fluoresce or not to fluoresce?

Thermally activated delayed fluorescence (TADF) has been widely applied to electroluminescent materials to take the best advantage of triplet excitons. For some materials, the TADF originates from high-level reverse intersystem crossing (hRISC), and has attracted much attention due to its high efficiency for utilizing the triplet excitons. However, reports concerning the mechanistic studies on the hRISC-TADF process and structure-property correlation are sparse. In this study, we prepared three compounds containing triphenylamine and benzophenone with different substitution positions, o-TPA-BP, m-TPA-BP, and p-TPA-BP, in which only p-TPA-BP displays strong luminescence and hRISC-TADF features. To investigate the mechanism of the substituent-position-dependent hRISC-TADF, ultrafast time-resolved spectroscopy was utilized to observe the deactivation pathways with the assistance of theoretical calculations. The results show that o-TPA-BP will not generate triplet species, and the triplet species for m-TPA-BP will rapidly deactivate. Only p-TPA-BP can transition back to the singlet state from the T2 state effectively and exhibit a large gap between T1 and T2 to favor the hRISC route. These results illustrate how the substitution position affects the ISC and further influences the luminescence properties, which can provide new insights for developing new high-efficiency luminescent materials.

PhyloCloud: an online platform for making sense of phylogenomic data.

Phylogenomics data have grown exponentially over the last decades. It is currently common for genome-wide projects to generate hundreds or even thousands of phylogenetic trees and multiple sequence alignments, which may also be very large in size. However, the analysis and interpretation of such data still depends on custom bioinformatic and visualisation workflows that are largely unattainable for non-expert users. Here, we present PhyloCloud, an online platform aimed at hosting, indexing and exploring large phylogenetic tree collections, providing also seamless access to common analyses and operations, such as node annotation, searching, topology editing, automatic tree rooting, orthology detection and more. In addition, PhyloCloud provides quick access to tools that allow users to build their own phylogenies using fast predefined workflows, graphically compare tree topologies, or query taxonomic databases such as NBCI or GTDB. Finally, PhyloCloud offers a novel tree visualisation system based on ETE Toolkit v4.0, which can be used to explore very large trees and enhance them with custom annotations and multiple sequence alignments. The platform allows for sharing tree collections and specific tree views via private links, or make them fully public, serving also as a repository of phylogenomic data. PhyloCloud is available at https://phylocloud.cgmlab.org.

Visualizing Triplet Energy Transfer in Organic Near-Infrared Phosphorescent Host-Guest Materials.

Limited by the energy gap law, purely organic materials with efficient near-infrared room temperature phosphorescence are rare and difficult to achieve. Additionally, the exciton transition process among different emitting species in host-guest phosphorescent materials remains elusive, presenting a significant academic challenge. Herein, using a modular nonbonding orbital-π bridge-nonbonding orbital (n-π-n) molecular design strategy, we develop a series of heavy atom-free phosphors. Systematic modification of the π-conjugated cores enables the construction of a library with tunable near-infrared phosphorescence from 655 to 710 nm. These phosphors exhibit excellent performance under ambient conditions when dispersed into a 4-bromobenzophenone host matrix, achieving an extended lifetime of 11.25 ms and a maximum phosphorescence efficiency of 4.2 %. Notably, by eliminating the interference from host phosphorescence, the exciton transition process in hybrid materials can be visualized under various excitation conditions. Spectroscopic analysis reveals that the improved phosphorescent performance of the guest originates from the triplet-triplet energy transfer of abundant triplet excitons generated independently by the host, rather than from enhanced intersystem crossing efficiency between the guest singlet state and the host triplet state. The findings provide in-depth insights into constructing novel near-infrared phosphors and exploring emission mechanisms of host-guest materials.

Insights into the Photodynamics of Fluorescence Emission and Singlet Oxygen Generation of Fluorogen Activating Protein-Malachite Green Systems.

The self-assembled fluorogen activating protein (FAP)-malachite green (MG) complex is a well-established protein-ligand system, which can realize binding-caused fluorescence turn-on of MG and singlet oxygen (1 O2 ) generation by MG iodination. To clarify the mechanism of fluorescence activation and 1 O2 generation, the photodynamics of different halogen-substituted MG derivatives and their corresponding FAP-MG complexes were studied by femtosecond transient absorption spectroscopy and theoretical computations. The results show that the rotation of MG is restricted by FAP binding, which prevents a rapid internal conversion to allow a longer lifetime for the excited MG to undergo fluorescence emission and intersystem crossing. Moreover, these FAP-MG complexes exhibit notably varied fluorescence quantum yields (ΦFL ) and 1 O2 yields. The study on the decay pathways indicates that such an anti-heavy atom effect predominately stems from the lifetimes of the excited-state species. The photodynamic mechanism study here will lead to more advanced FAP-MG systems with high spatiotemporal resolution.

Ultrafast excited-state energy dissipation pathway of diethylamino hydroxybenzoyl hexyl benzoate (DHHB) via the nanoparticles.

The organic UVA filter is popularized in sunscreen cosmetics due to the advantages of excellent light stability and high molar extinction coefficient. However, the poor water solubility of organic UV filters has been a common problem. Given that nanoparticles (NPs) can significantly improve the water solubility of organic chemicals. Meanwhile, the excited-state relaxation pathways of NPs might differ from their solution. Here, the NPs of diethylamino hydroxybenzoyl hexyl benzoate (DHHB), a popular organic UVA filter, were prepared by an advanced ultrasonic micro-flow reactor. The surfactant (sodium dodecyl sulfate) was selected as an effective stabilizer to prevent the self-aggregation of the NPs for DHHB. Femtosecond transient ultrafast spectroscopy (fs-TA) and theoretical calculations were utilized to trace and explain the excited-state evolution of DHHB in NPs suspension and its solution. The results reveal that the surfactant-stabilized NPs of DHHB reserve a similarly good performance of ultrafast excited-state relaxation. The stability characterization experiments demonstrate that the strategy of surfactant-stabilized NPs for sunscreen chemicals can maintain its stability and enhance the water solubility of DHHB compared with that of the solution phase. Therefore, the surfactant-stabilized NPs of organic UV filters are an effective method to improve water solubility and keep the stability from aggregation and photoexcitation.

Uncovering the substituted-position effect on excited-state evolution of benzophenone-phenothiazine dyads.

Photofunctional materials based on donor-acceptor molecules have drawn intense attention due to their unique optical properties. Importantly, Systematic investigation of substitution effects on excited-state charge transfer dynamics of donor-acceptor molecules is a powerful approach for identifying application-relevant design principles. Here, by coupling phenothiazine (PTZ) at the ortho-, meta-, and para-positions of the benzene ring of benzophenone (BP), three regioisomeric BP-PTZ dyads were designed to understand the relationship between substituted positions and excited-state evolution channels. Ultrafast transient absorption is used to detect and trace the transient species and related evolution channels of BP-PTZ dyads at excited state. In a non-polar solvent, BP-o-PTZ undergoes the through-space charge transfer process to produce a singlet charge-transfer (1CT) state, which subsequently proceeds the intersystem crossing process and transforms into a triplet charge-transfer (3CT) state; BP-m-PTZ experiences intramolecular charge transfer (ICT) process to generate the 1CT state, which subsequently transforms into the 3CT state by the intersystem crossing (ISC) and finally converts into the local-excited triplet (3LE) state; as for BP-p-PTZ, only 3LE states can be detected after the ISC process from the 1CT state. On the other hand, the twisted ICT states are generated via twisted motion between the donor and acceptor for all BP-PTZ dyads or planarization of the PTZ unit in high polar solvents. The excited-state theoretical calculations unveil that the features of ICT and intramolecular interaction between the three dyads play a decisive role in determining the through-bond charge transfer and through-space charge transfer processes. Also, these results demonstrate that the excited-state evolution channels of PTZ derivatives could be modified by tuning the substituted positions of the donor-acceptor dyads. This study provides a deep perspective for the substitute-position effect on donor-acceptor-type PTZ derivatives.

A multifunctional fluorescent sensor for Ag+ and Hg2+ detection in seawater.

In order to detect Ag+ and Hg2+ in seawater, we explored a multifunctional fluorescence sensor. A multifunctional Ag+ and Hg2+ sensor was designed by using gold nanoparticles (AuNPs) as quenching agent, PicoGreen dye as fluorescent probe of base pairing double-stranded deoxyribonucleic acid (DNA), and combining the characteristics of Ag+ making C base mismatch and Hg2+ making T base mismatch. Meanwhile, the DNA logic gate was constructed by establishing logic circuit, truth table, and logic formula. The relevant performances of the sensor were investigated. The results revealed that the sensor can detect Ag+ in the range of 100 to 700 nM with R2 = 0.98129, and its detection limit is 16.88 nM (3σ/slope). The detection range of Hg2+is 100-900 nM with R2 = 0.99725, and the detection limit is 5.59 nM (3σ/slope). An AND-AND-NOR-AND molecular logic gate has been successfully designed. With the characteristics of high sensitivity, multifunction, and low cost, the recommended detection method has the potential to be applied to the detection of Ag+ and Hg2+ in seawater.

Extension of Non-alternant Nanographenes Containing Nitrogen-Doped Stone-Thrower-Wales Defects.

Non-alternant topologies have attracted considerable attention due to their unique physiochemical characteristics in recent years. Here, three novel topological nanographenes molecular models of nitrogen-doped Stone-Thrower-Wales (S-T-W) defects were achieved through intramolecular direct arylation. Their chemical structures were unambiguously elucidated by single-crystal analysis. Among them, threefold intramolecular direct arylation compound (C42 H21 N) is the largest nanographene bearing a N-doped non-alternant topology to date, in which the non-benzenoid rings account for 83 % of the total molecular skeleton. The absorption maxima of this compound was located in the near-infrared region with a long tail up to 900 nm, which was much longer than those reported for similarly sized N-doped nanographene with six-membered rings (C40 H15 N). In addition, the electronic energy gaps of these series compounds clearly decreased with the introduction of non-alternant topologies (from 2.27 eV to 1.50 eV). It is noteworthy that C42 H21 N possesses such a low energy gap (Eg opt =1.40 eV; Eg cv =1.50 eV), yet is highly stable under ambient conditions. Our work reported herein demonstrates that the non-alternant topology could significantly influence the electronic configurations of nanocarbons, where the introduction of a non-alternanting topology may be an effective way to narrow the energy gap without extending the molecular π-conjugation.

Revealing the Photophysical and Photochemical Reaction Processes of Carprofen in Different Solutions via Ultrafast Femtosecond to Nanosecond Transient Absorption.

Carprofen (CP), one kind of a nonsteroidal anti-inflammatory drug, exhibits phototoxic side effects in physiology, while its phototoxic mechanism is ambiguous. To uncover CP's photophysical and photochemical reaction processes, femtosecond to nanosecond transient absorption spectroscopies were employed to directly detect excited states and transient intermediates of CP upon UV irradiation in pure acetonitrile (MeCN), MeCN/water 1:1, and acid/alkaline buffer solutions. The transient absorption data together with DFT calculations were integrated to elucidate mechanisms for photochemical reactions of CP in different solutions. The associated photophysical and photochemical reaction pathways are dependent on various solution environments. In a pure MeCN solvent, CP is excited to a singlet state (S1) and rapidly interacts with the solvent to proceed solvent rearrangement (SR). It then undergoes vibrational cooling (VC) and proceeds intersystem crossing (ISC) to produce the lowest triplet state (3CP). 3CP finally decays to the ground state. While in a MeCN/water 1:1 solution, deprotonated S1 of CP experiences SR and VC processes, and then it is promoted to a deprotonated triplet state (3CP-). 3CP- undergoes the parallel reactions: dechlorination to a phenyl radical (2CP-) and decarboxylation to a T1 anion (3CP-(de-CO2)). Finally, both intermediates produce the radical anion species 2CP-(de-CO2). In a pH = 7.4 (MeCN/PBS 1:1) solution, 3CP- can be converted into 2CP-(de-CO2) more quickly. Interestingly, we found that the dechlorination step can be promoted in an alkaline solution. Phenyl and chlorine radicals produced in an aqueous solution may be the root cause of the drug's harmful side effects on the human body. This may be useful to guide the design of related CP drugs with minimal phototoxicity in the pharmaceutical process.

Ultrafast study of substituted-position-dependent excited-state evolution in benzophenone-carbazole dyads.

Donor and acceptor (D-A) compounds based on benzophenone (BP) and carbazole (Cz) were recently reported to exhibit an extraordinary long afterglow phosphorescence in the solid state. However, the BP derivatives' mechanism of long afterglow phosphorescence is obscure. BP-o-Cz, BP-m-Cz, and BP-p-Cz were designed by coupling Cz at the ortho-, meta- and para-positions of the BP's benzene ring to uncover the excited-state evolution of BP-Cz molecules. Femtosecond and nanosecond transient absorption and excited-state theoretical calculations were carried out to detect and trace the photophysical process of BP-Cz dyads. After the excitation, all dyads experience intramolecular charge transfer (ICT) and intersystem crossing (ISC) processes. The resulting charge-transfer (1CT and 3CT) state of BP-o-Cz will decay to the ground state directly and quickly via the fast charge recombination (CR) process, which may be caused by through-space D-A interaction due to the enforced proximity between BP and Cz. In contrast, for BP-m-Cz and BP-p-Cz dyads, the complete separation of HOMOs and LUMOs leads to extended ICT and slow CR processes, producing an obvious Cz cation radical intermediate and an ultralong-lived triplet state species after the 3CT. Herein, we demonstrated that the excited-state evolution channels could be modified by tuning the substituted positions of D-A dyads. This may pave the way for designing efficient D-A type luminescent materials.

Disentangling Multiple Effects on Excited-State Intramolecular Charge Transfer among Asymmetrical Tripartite PPI-TPA/PCz Triads.

By utilizing the bipolarity of 1,2-diphenylphenanthroimidazole (PPI), two types of asymmetrical tripartite triads (PPI-TPA and PPI-PCz) were designed with triphenylamine (TPA) and 9-phenylcarbazole (PCz). These triads are deep-blue luminescent materials with a high fluorescence quantum yield of nearly 100 %. To trace the photophysical behaviors of these triads, their excited-state evolution channels and interchromophoric interactions were investigated by ultrafast time-resolved transient absorption and excited-state theoretical calculations. The results suggest that the electronic nature, asymmetrical tripartite structure, and electron-hole distance of these triads, as well as solvent polarity, determine the lifetime of intramolecular charge transfer (ICT). Interestingly, PPI-PCz triads show anti-Kasha ICT, and the charge-transfer direction among the triads is adjustable. For the PPI-TPA triad, the electron is transferred from TPA to PPI, whereas for the PPI-PCz triad the electron is pushed from PPI to PCz. Exploration of the excited-state ICT in these triads may pave the way to design better luminescent materials in the future.

The eukaryotic linear motif resource - 2018 update.

Short linear motifs (SLiMs) are protein binding modules that play major roles in almost all cellular processes. SLiMs are short, often highly degenerate, difficult to characterize and hard to detect. The eukaryotic linear motif (ELM) resource (elm.eu.org) is dedicated to SLiMs, consisting of a manually curated database of over 275 motif classes and over 3000 motif instances, and a pipeline to discover candidate SLiMs in protein sequences. For 15 years, ELM has been one of the major resources for motif research. In this database update, we present the latest additions to the database including 32 new motif classes, and new features including Uniprot and Reactome integration. Finally, to help provide cellular context, we present some biological insights about SLiMs in the cell cycle, as targets for bacterial pathogenicity and their functionality in the human kinome.

Nickel Metal-Organic Framework Monolayers for Photoreduction of Diluted CO2 : Metal-Node-Dependent Activity and Selectivity.

Photocatalytic conversion of diluted CO2 into solar fuel is highly appealing yet still in its infancy. Herein, we demonstrate the metal-node-dependent performance for photoreduction of diluted CO2 by constructing Ni metal-organic framework (MOF) monolayers (Ni MOLs). In diluted CO2 (10 %), Ni MOLs exhibit a highest apparent quantum yield of 1.96 % with a CO selectivity of 96.8 %, which not only exceeds reported systems in diluted CO2 but also is superior to most catalysts in pure CO2 . Whereas isostructural Co MOLs is almost inactive in diluted CO2 , indicating the performance is dependent on the metal nodes. Experimental and theoretical investigations show that strong CO2 binding affinity of Ni MOLs is the crucial factor, which stabilizes the Ni-CO2 adducts and facilitates CO2 -to-CO conversion.

Preparation of a novel DNA-imprinted sensor based on chitosan and its highly sensitive detection of Pb2.

Lead ion is very harmful to the environment, so it is very important to study its detection methods. In this study, a novel electrochemical sensor was constructed by modifying deoxyribonucleic acid (DNA) on the electrode, which can be used for the detection of Pb2+ in the environment. Part of the mixed solution of chitosan (CS) and Pb2+ template ions was dropped onto the surface of a glassy carbon electrode. CS-Pb2+ film was cross-linked through sodium tripolyphosphate. And a novel DNA-imprinted sensor was prepared by electrodepositing CS-Pb2+ thin film with gold nanoparticles (AuNPs), removing Pb2+ templates, and immobilizing specific double-stranded DNA. The electroactive area, surface morphology, sensitivity, and electrochemical reaction mechanism of the DNA-imprinted sensor were analyzed. The elementary reaction steps were studied through electrochemical reaction kinetics analysis. The experimental results indicate that the DNA-imprinted electrochemical biosensor can quantitatively detect Pb2+ in the range of 10-100 µM (R2 = 0.9935), and its detection limit is 6.5074 µM (3σ/slope). The sensitivity of the electrochemical biosensor is 1.55233 × 10-6 A/µM, and its active areas is 6.233 cm2. The desorption mechanism and adsorption mechanism have been explored through dynamic parameter analysis. The novel DNA imprinted electrochemical biosensor developed in this paper provides a robust method for detecting lead ions in solution. Additionally, it establishes a solid groundwork for detecting other metal ions.

The Mechanism of Sodium Sulfate Coupled with Anaerobic Methane Oxidation Mitigating Methane Production in Beef Cattle.

The aim of this experiment is to explore the effect of sodium sulfate (Na2SO4) on methane reduction in the rumen, and its impact on anaerobic methane-oxidizing archaea (ANME). Using mixed rumen fluid from four Angus cattle fistulas, this study conducted an in vitro fermentation. Adding Na2SO4 to the fermentation substrate resulted in sulfur concentrations in the substrate of 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, and 2.4%. The gas production rate and methane yield were measured using an in vitro gas production method. Subsequently, the fermentation fluid was collected to determine the fermentation parameters. The presence of ANME in the fermentation broth, as well as the relationship between the number of bacteria, archaea, sulfate reducing bacteria (SRB), ANME, and the amount of Na2SO4 added to the substrate, were measured using qPCR. The results showed that: (1) the addition of Na2SO4 could significantly reduce CH4 production and was negatively correlated with CO2 production; (2) ANME-1 and ANME-2c did exist in the fermentation broth; (3) the total number of archaea, SRB, ANME-1, and ANME-2c increased with the elevation of Na2SO4. The above results indicated that Na2SO4 could mitigate methane production via sulfate-dependent anaerobic methane oxidation (S-DAMO) in the rumen. In the future management of beef cattle, including sodium sulfate in their diet can stimulate S-DAMO activity, thereby promoting a reduction in methane emissions.

The Effect of Yucca schidigera Extract on Serum Metabolites of Angus Crossbreed Steers with Metabolomics.

This study was conducted to explore the potential effect of Yucca schidigera extract (YSE) on the metabolism of beef cattle. Thirty Angus crossbreed steers were selected, with an initial mean body weight of 506.6 ± 33.3 kg, and assigned to two treatments: a diet with no additives (CON group) and a diet supplemented with 1.75 g/kg of YSE (YSE group) (on a dry matter basis). The experiment lasted for 104 days, with 14 days for adaptation. The results showed that adding YSE could significantly improve the average daily gain (ADG) from 1 to 59 d (15.38%) (p = 0.01) and 1 to 90 d (11.38%) (p < 0.01), as well as dry matter digestibility (DMD) (0.84%) (p < 0.05). The contents of alanine aminotransferase, aspartate aminotransferase, and bilirubin and the total antioxidant capacity were increased and blood urea was reduced in the YSE group, compared to the CON group (p < 0.05). Both the glycerophospholipids and bile acids, including phosphocholine, glycerophosphocholine, PC(15:0/18:2(9Z,12Z)), PE(18:0/20:3(5Z,8Z,11Z)), PE(18:3(6Z,9Z,12Z)/P-18:0), LysoPC(15:0), LysoPC(17:0), LysoPC(18:0), LysoPC(20:5(5Z,8Z,11Z,14Z,17Z)), deoxycholic acid, glycocholic acid, and cholic acid, were upregulated by the addition of YSE. In summary, YSE may improve the ADG by increasing the blood total antioxidant capacity and glycerophospholipid synthesis, maintaining steers under a healthy status that is beneficial for growth. Furthermore, YSE may also increase the expression of bile acid synthesis, thereby promoting DMD, which, in turn, offers more nutrients available for growth.

Synthesis, Structures, and Chiroptical Properties of NBN-Doped Helicenes with Boron Atoms in the Inner Rims.

The precise synthesis of helicenes with topologically defined length and specific heteroatomic perturbation in the screw-like conjugated skeletons plays an emerging role in the manipulation of chiral materials. Facile, selective, and programmable routes to helicenes or heterohelicenes are highly desirable yet challenging for structure-chiroptical property relationship studies. Herein, we report the synthesis and characterization of NBN-doped helicenes with boron atoms in the inner rims, enabled by the highly regioselective one-pot borylation of rationally designed precursors with, namely, fold-in or pan-out manner. The incorporation of nonbonded boron and nitrogen atoms resulted in narrow-band emission and improved optical properties for the single-stranded carbon helix. In addition, numbers and arrangement modes of fused six-membered rings have distinct effects on configurational stability and chiroptical properties, revealing that BN-[6]H with strong circular dichroism is a promising candidate for chiral sensors. The combination of experimental and theoretical studies on these helical structures might provide insights into the design of helically chiral small-molecule-based sensors or emitters.

Aberrant glycosylation in schizophrenia: insights into pathophysiological mechanisms and therapeutic potentials.

Schizophrenia (SCZ) is a severe neuropsychiatric disorder characterized by cognitive, affective, and social dysfunction, resulting in hallucinations, delusions, emotional blunting, and disordered thinking. In recent years, proteomics has been increasingly influential in SCZ research. Glycosylation, a key post-translational modification, can alter neuronal stability and normal signaling in the nervous system by affecting protein folding, stability, and cellular signaling. Recent research evidence suggests that abnormal glycosylation patterns exist in different brain regions in autopsy samples from SCZ patients, and that there are significant differences in various glycosylation modification types and glycosylation modifying enzymes. Therefore, this review explores the mechanisms of aberrant modifications of N-glycosylation, O-glycosylation, glycosyltransferases, and polysialic acid in the brains of SCZ patients, emphasizing their roles in neurotransmitter receptor function, synaptic plasticity, and neural adhesion. Additionally, the effects of antipsychotic drugs on glycosylation processes and the potential for glycosylation-targeted therapies are discussed. By integrating these findings, this review aims to provide a comprehensive perspective to further understand the role of aberrant glycosylation modifications in the pathophysiology of SCZ.

NIR-II emissive anionic copper nanoclusters with intrinsic photoredox activity in single-electron transfer.

Ultrasmall copper nanoclusters have recently emerged as promising photocatalysts for organic synthesis, owing to their exceptional light absorption ability and large surface areas for efficient interactions with substrates. Despite significant advances in cluster-based visible-light photocatalysis, the types of organic transformations that copper nanoclusters can catalyze remain limited to date. Herein, we report a structurally well-defined anionic Cu40 nanocluster that emits in the second near-infrared region (NIR-II, 1000-1700 nm) after photoexcitation and can conduct single-electron transfer with fluoroalkyl iodides without the need for external ligand activation. This photoredox-active copper nanocluster efficiently catalyzes the three-component radical couplings of alkenes, fluoroalkyl iodides, and trimethylsilyl cyanide under blue-LED irradiation at room temperature. A variety of fluorine-containing electrophiles and a cyanide nucleophile can be added onto an array of alkenes, including styrenes and aliphatic olefins. Our current work demonstrates the viability of using readily accessible metal nanoclusters to establish photocatalytic systems with a high degree of practicality and reaction complexity.