Atomically precise copper clusters are highly desirable catalysts for electrocatalytic CO2 reduction reaction (CO2RR) and provide an ideal platform for elaborating structure–activity relationships. ...However, systematic comparative studies of Cu cluster isomers for electrocatalytic CO2RR are lacking because they are challenging to synthesize. A group of structurally precise Cu8 cluster isomers with different core structures (cube‐ and ditetrahedron‐shaped) were developed and investigated for highly active and selective CO2 reduction. Electrocatalytic measurements showed that the ditetrahedron‐shaped Cu8 cluster exhibited a higher FEHCOOH (≈92 %) at −1.0 V and higher selectivity than the cube‐shaped cluster. Theoretical investigations revealed different levels of competitiveness with the hydrogen evolution reaction on the respective core‐shaped Cu8 clusters and decreased free energies for the adsorbed HCOO* intermediates on the ditetrahedron‐shaped Cu8 clusters.
A group of atomically precise Cu8 cluster isomers with two core structures (cube‐ and ditetrahedron‐shaped) were investigated for highly active and selective CO2 reduction. A difference in catalytic performance was attributed to variable metal core arrangements hidden in Cu8 nanoclusters. The ditetrahedron‐shaped cluster exhibits a high Faradaic efficiency for formic acid generation (FEHCOOH) almost two times that of the cube‐shaped cluster.
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Atomically precise enantiomeric metal clusters are scarce, and copper(I) alkynyl clusters with intense circularly polarized luminescence (CPL) responses have not been reported. A pair of chiral ...alkynyl ligands, (R/S)‐2‐diphenyl‐2‐hydroxylmethylpyrrolidine‐1‐propyne (abbreviated as R/S‐DPM) we successfully prepared and single crystals were characterized of optically pure enantiomeric pair of atomically‐precise copper(I) clusters, Cu14(R/S‐DPM)8(PF6)6 (denoted as R/S‐Cu14), which feature bright red luminescence and CPL with a high luminescence anisotropy factor (glum). A dilute solution containing R/S‐Cu14 was nonluminescent and CPL inactive at room temperature. Crystallization‐ and aggregation‐induced emission (CIE and AIE, respectively) contribute to the triggering of the CPL of R/S‐Cu14 in the crystalline and aggregated states. Their AIE behavior and good biocompatibility indicated applications of these copper(I) clusters in cell imaging in HeLa and NG108‐15 cells.
Atomically precise chiral CuI alkynyl nanoclusters R/S‐Cu14 with inherent chirality were synthesized for the first time. Crystallization‐ and aggregation‐induced emission (CIE and AIE, respectively) trigger circularly polarized luminescence (CPL) with an unprecedented luminescence anisotropy factor (glum).
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An efficient and readily scalable thioetherification between 1,1‐diphenylethene (DPE) and sodium arylsulfinate was developed for the synthesis of 1,1‐diphenylvinylsulfide (DPVS) with the yield up to ...99 %. The photophysical properties of DPVS show that the introduction of arylsulfenyl groups onto the parent molecule DPE makes DPVS a novel type of aggregation‐induced emission (AIE) luminogen (AIEgen) with large Stoke's shift (up to 188 nm). These DPVS possess AIE properties due to restriction of intramolecular motions (RIM), as demonstrated by crystal structure analysis. Importantly, the AIE performance of DPVS can be applied to sense the nitroaromatic explosive picric acid in aqueous systems through a “turn‐off” response.
A simple thioetherification between 1,1‐diphenylethene as an aggregation‐induced emission (AIE)‐imparting unit and sodium sulfinates provides a new route for the conversion of compounds with aggregation‐caused quenching (ACQ) properties into AIE luminogens. This reaction delivers up to 99 % yield under mild conditions without additional oxidant, and gives access to novel trisubstituted‐ethene‐type AIEgens with potential for use in sensing applications.
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Subtle tailoring of gold nanoclusters (NCs) could significantly change their physicochemical properties. However, direct comparison of the catalytic performance of gold NCs with identical metal cores ...but distinct ligand shells is rarely elucidated. In this work, a novel gold NC, Au28(C2B10H11S)12(tht)4Cl4 (Au28‐S), was isolated by a facile self‐reducing synthesis. Au28‐S adopts an identical Au28 metal framework to that of the reported alkynyl‐protected Au28‐C. The different protective layers lead to distinctions in their electronic structure and optical properties. Furthermore, Au28‐S shows better catalytic activity for the electrochemical reduction of CO2 to CO. Theoretical calculations identified the active sites and shed light on the catalytic mechanism to elucidate the different catalytic performances. This work provides an ideal platform to study the protective layer‐activity relationship of gold NCs, and may also provide guidance in the design of metal NC‐based catalysts.
A carboranethiolate‐protected gold nanocluster Au28‐S was fabricated by a facile self‐reducing synthesis. Au28‐S has an identical metal core to the reported Au28‐C but different peripheral ligands. This ligand‐shell tailoring led to obvious differences in their electronic structures and optical properties. Compared to Au28‐C, Au28‐S shows superior catalytic activity and selectivity for the electrocatalytic CO2 reduction reaction.
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Abstract
Ratiometric luminescent oxygen sensing based on dual fluorescence and phosphorescence emission in a single matrix is highly desirable, yet the designed synthesis remains challenging. ...Silver-chalcogenolate-cluster-based metal-organic frameworks that combine the advantages of silver clusters and metal-organic frameworks have displayed unique luminescent properties. Herein, we rationally introduce −NH
2
groups on the linkers of a silver-chalcogenolate-cluster-based metal-organic framework (Ag
12
bpy-NH
2
) to tune the intersystem crossing, achieving a dual fluorescence-phosphorescence emission from the same linker chromophore. The blue fluorescence component has a 100-nm gap in wavelength and 8,500,000-fold difference in lifetime relative to a yellow phosphorescence component. Ag
12
bpy-NH
2
quantifies oxygen during hypoxia with the limit of detection of as low as 0.1 ppm and 0.3 s response time, which is visualized by the naked eye. Our work shows that metal cluster-based MOFs have great potential in luminescent sensing, and the longer-lived charge-separated states could find more photofunctional applications in solar energy transformation and photocatalysis.
Structure evolution has become an effective way to assemble novel monolayer‐protected metal nanomolecules. However, evolution with alkynyl‐stabilized metal clusters still remains rarely explored. ...Herein, we present a carboranealkynyl‐protected gold nanocluster Au28(C4B10H11)12(tht)83+ (Au28, tht=tetrahydrothiophene) possessing an open‐shell electronic structure with 13 free electrons, which was isolated by a facile self‐reduction method with 9‐HC≡C‐closo‐1,2‐C2B10H11 as the two‐in‐one reducing and protecting agent. Notably, Au28 undergoes a complete transformation in methanol into a stable and smaller‐sized nanocluster Au23(C4B10H11)9(tht)62+ (Au23) bearing 12 valence electrons and crystal‐field‐like split superatomic 1D orbitals. The transformation process was systematically monitored with ESI‐MS and UV/Vis absorption spectra. Au28 and Au23 both display optical absorption covering the UV/Vis–NIR range and NIR emission, which facilitates their potential application in the biomedical and photocatalytic fields.
A carboranealkynyl‐protected gold nanocluster Au28 possessing an open‐shell electronic structure with 13 valence electrons was isolated through a facile self‐reduction method in which it undergoes a complete transformation in methanol into a smaller‐sized cluster Au23 bearing 12 valence electrons and crystal‐field‐like split superatomic 1D orbitals. Au28 and Au23 both display optical absorption covering the UV/Vis–NIR range and NIR emission.
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Convenient generation of stable superatomic silver clusters and their systematic site-specific tailoring and directional assembly present an enduring and significant challenge. In this work, we ...prepared a face-centered cubic (fcc) array of Ag14 superatoms protected by face-capping 1,2-dithiolate-o-carborane (C2B10H10S2) ligands, each produced from 1-thiol-o-carborane in crystallization with simultaneous reduction of Ag+ to Ag0. We find that the corner N-donor ligands contribute predominately to the stability and luminescence of the Ag14 superatom. As the first-formed nanocluster Ag14(C2B10H10S2)6(CH3CN)8·4CH3CN (NC-1) with labile vertex-coordinated CH3CN ligands is highly unstable, monodendate pyridine ligands were used to replace these CH3CN species site-specifically, giving Ag14(C2B10H10S2)6(pyridine/p-methylpyridine)8 (NCs-2,3) in gram scale with its core structure intact, which features ultrastability up to 150 °C in air. Moreover, using bidentate N-containing ligands to bridge the superatomic Ag14 building blocks, we constructed an unprecedented hierarchical series of 1D-to-3D superatomic silver cluster-assembled materials (SCAM-1,2,3,4), and SCAM-4 is air-stable up to 220 °C. Furthermore, this series of stable solid-state superatomic-nanocluster materials exhibit tunable dual emission with wide-range thermochromism. The present study constitutes a major step toward the development of ligand-modulation of the structure, stability, assembly, and functionality of superatomic silver nanoclusters.
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Silver cluster-assembled materials (SCAMs), by virtue of their tunable structure, accessible surface area and excellent stability, hold great promise as highly efficient catalysts. Herein, we report ...a new SCAM Ag12(S t Bu)6(CF3COO)3(TPyP) n (denoted as Ag12TPyP) composed of a Ag12 chalcogenolate cluster core stabilized by porphyrinic ligands. Ag12TPyP showed superior sulfur mustard simulant (2-chloroethyl ethyl sulfide, CEES) degradation efficiency and achieved a half lifetime (t 1/2) of 1.5 min with 100% selectivity. The experimental results demonstrated that synergistic effects between the silver cluster and photosensitizer ligand promote the efficiency of the generation of singlet oxygen (1O2), which accelerates the decontamination rate. Additionally, benefiting from strong affinity between the silver cluster and CEES, Ag12TPyP exhibits a CEES uptake of 74.2 mg g–1. This work demonstrates that SCAMs offer a new route to the rational design of novel materials for the detoxification of mustard gas.
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Alloying is an efficient chemistry to tailor the properties of metal clusters. As a class of promising radiosensitizers, most previously reported metal clusters exhibit unitary function and cannot ...overcome radioresistance of hypoxic tumors. Here, atomically precise alloy clusters Pt2M4 (M = Au, Ag, Cu) are synthesized with bright luminescence and adequate biocompatibility, and their composition‐dependent enzyme mimicking activity and radiosensitizing effect is explored. Specifically, only the Pt2Au4 cluster displays catalase‐like activity, while the others do not have clusterzyme properties, and its radiosensitizing effect is the highest among all the alloy clusters tested. By taking advantage of the sustainable production of O2 via the decomposition of endogenous H2O2, the Pt2Au4 cluster modulates tumor hypoxia as well as increases the efficacy of radiotherapy. This work thus advances the cluster alloying strategy to produce multifunctional therapeutic agents for improving hypoxic tumor therapy.
Atomically precise alloy clusters Pt2M4 (M = Au, Ag, Cu) are synthesized with bright luminescence and adequate biocompatibility. The experimental results reveal that the Pt2Au4 cluster displays catalase‐like activity and its radiosensitizing effect is the highest. By taking advantage of the sustainable production of O2 via decomposition of endogenous H2O2, the Pt2Au4 cluster modulates tumor hypoxia as well as increases the efficacy of radiotherapy.
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Six novel benzimidazole‐based D‐π‐A compounds 4 a–4 f were concisely synthesized by attaching different donor/acceptor units to the skeleton of 1,3‐bis(1H‐benzimidazol‐2‐yl)benzene on its 5‐position ...through an ethynyl link. Due to the twisted conformation and effective conjugation structure, these dual‐state emission (DSE) molecules show intense and multifarious photoluminescence, and their fluorescence quantum yields in solution and solid state can be up to 96.16 and 69.82 %, respectively. Especially, for excellent photostability, obvious solvatofluorochromic and extraordinary wide range of solvent compatibility, DSE molecule 4 a is a multifunctional fluorescent probe for the visual detection of nitroaromatic compounds (NACs) with the limit of detection as low as 10−7 M. The quenching mechanism has been proved as the results of photoinduced electron transfer and fluorescence resonance energy transfer processes. Importantly, probe 4 a can sensitively detect NACs not only in real water samples, but also on 4 a‐coated strips and 4 a@PBAT thin films.
Novel benzimidazole‐based D‐π‐A fluorophores are rationally designed and concisely synthesized. Six compounds 4 a–4 f, as dual‐state emission (DSE) materials, exhibit excellent photostability, solvatofluorochromic and extraordinary wide range of solvent compatibility. Among them, the DSE material 4 a is not only reasonably developed as a multifunctional fluorescent probe for sensitive detection of nitroaromatic compounds (NACs) in aqueous system, but also processed into test strips and thin films for visual detection of NACs.
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