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Facile Construction of Defect-rich Rhenium Disulfide/Graphite Carbon Nitride Heterojunction via Electrostatic Assembly for fast Charge Separation and Photoactivity Enhancement
摘要： Graphite carbon nitride (CN) is one of the most researched visible light photocatalysts, but it still cannot be used practically because of its low photoactivity resulting mainly from rapid photogenerated charge recombination. To accelerate charge separation, CN was herein electrostatically assembled with ReS2, a two-dimensional semiconductor to construct heterojunction for the first time. The electrostatic and coordination interactions between CN and defect-rich ReS2 make them close contact to form heterojunctions. The ReS2/CN heterojunction exhibits higher photocatalytic performance in pollutant degradation owing to faster generation of reactive oxygen species than CN, as well as increased visible and near-infrared light absorption because of strong photoabsorption of defect-rich ReS2. The accelerated reactive oxygen species generation for the heterojunction arises from accelerated charge separation, especially fast transfer of holes from CN to ReS2 in assistance of interfacial electric field and great valance-band edge difference. This work provides a novel CN-based heterojunction for photoactivity improvement and illustrates significance of electrostatic attraction in fabricating heterojunctions.
关键词： electrostatic interaction,photocatalytic,rhenium disulfide,graphite carbon nitride,charge separation
更新于2025-11-21 11:03:13
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Sensitized photochemical CO2 reduction by hetero-Pacman compounds linking a Re(I) tricarbonyl with a porphyrin unit
摘要： The hetero-Pacman architecture places two different metal coordination sites in close proximity, which can support efficient energy and/or electron transfer and allow for cooperative activation of small molecules. Herein, we present the synthesis of dyads consisting of a porphyrin unit as photosensitizer and a rhenium unit as catalytically active site, which are held together by the rigid xanthene backbone. Mononuclear [(NN)Re(CO)3(Cl)] complexes for CO2 reduction where NN represents a bidentate diimine ligand (e.g. bipyridine or phenanthroline) lack light absorption in the visible region, resulting in poor photocatalysis upon illumination with visible light. In order to improve their visible light absorption, we have focused on the incorporation of a strongly absorbing free base or zinc porphyrin unit. Resulting photocatalytic experiments showed a strong dependence of catalytic performance on both the type of photosensitizer and also the excitation wavelengths. Most notably, the intramolecular hetero-Pacman system containing a zinc porphyrin unit showed much better catalytic activity in the visible region (excitation wavelengths >450 nm) than the free base version, the corresponding mononuclear rhenium compound or an intermolecular system comprised of a 1:1 mixture of the mononuclear analogues.
关键词： photocatalysis,CO2 reduction,electron transfer,porphyrin,rhenium
更新于2025-11-19 16:56:35
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Luminescent rhenium(I) carbonyl complex with redox noninnocent ONS donor azo-phenol ligand: Synthesis, X-ray structure, photophysical properties and live cell imaging
摘要： Herein, we have synthesized a new fluorescent rhenium(I) carbonyl complex 1, bearing {Re(CO)3}+ core with ONS donor thioether containing azo-phenol redox noninnocent ligand. The distorted octahedral geometry of the complex is confirmed by single crystal X-ray diffraction method. Cyclic voltammogram in acetonitrile exhibits irreversible oxidation peak (Epa = 1.36 V) along with quasi-reversible reduction peak at E1/2 = -0.92 V (ΔE = 210 mV). The complex exhibits low energy emission band at 525 nm with high emission quantum yield (Φ = 0.115). Cytotoxicity of the complex is studied by MTT method with human breast cancer cell lines (MCF-7) and IC50 value is found to be 23.6 μM. In presence of the complex (10 μM) a bright green fluorescence image of MCF-7 cell lines is observed under fluorescence microscope.
关键词： Electrochemistry,ONS donor ligand,MTT assay,Rhenium(I) carbonyl complex,Live cell imaging
更新于2025-11-19 16:46:39
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Surface-Immobilized Conjugated Polymers Incorporating Rhenium Bipyridine Motifs for Electrocatalytic and Photocatalytic CO <sub/>2</sub> Reduction
摘要： The solar-driven conversion of CO2 to value-added products provides a promising route for solar energy storage and atmospheric CO2 remediation. In this report, a variety of supporting electrode materials were successfully modified with a [2,2′-bipyridine]-5,5′-bis(diazonium) rhenium complex through a surface-localized electropolymerization method. Physical characterization of the resulting multilayer films confirms that the coordination environments of the rhenium bipyridine tricarbonyl sites are preserved upon immobilization and that the polymerized catalyst moieties exhibit long-range structural order with uniform film growth. UV?vis studies reveal additional absorption bands in the visible region for the polymeric films that are not present in the analogous rhenium bipyridine complexes. Electrochemical studies with modified graphite rod electrodes show that the electrocatalytic activity of these films increases with catalyst loading up to an optimal value, beyond which electron and mass transport through the material become rate-limiting. Electrocatalytic studies performed at ?2.25 V vs Fc/Fc+ for 2 h reveal CO production with faradaic efficiencies and turnover numbers up to 99% and 3606, respectively. Photocatalytic studies of the modified TiO2 devices demonstrate enhanced activity at low catalyst loadings, with turnover numbers up to 70 during 5 h of irradiation.
关键词： metallopolymers,surface modification,photocatalysis,rhenium bipyridine,solar energy conversion,electrocatalysis
更新于2025-09-23 15:23:52
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Rhenium and technetium-complexed silicon rhodamines as near-infrared imaging probes for bimodal SPECT- and optical imaging
摘要： Fluorescent Si-rhodamines were modified to enable complexation with the Re(I)- and 99mTc(I)-tricarbonyl core. The corresponding complexes exhibit suitable properties as bimodal imaging probes for SPECT- and optical imaging in vitro. Importantly, the novel in aqueous solution stable, functionalized Si-rhodamines retain favourable optical properties after complexation (QY=0.09, λabs=654 nm, λem=669 nm in PBS) and show promising near-infrared optical properties for potential in vivo applications enabling bimodal scintigraphic imaging and optical imaging, e.g. used in radio- and fluorescence-guided tumor resection.
关键词： SPECT,Optical imaging,Near-infrared imaging,Technetium,Rhenium,Silicon rhodamines
更新于2025-09-23 15:21:01
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Van der Waals broken-gap p-n heterojunction tunnel diode based on black phosphorus and rhenium disulfide
摘要： The broken-gap type-III van der Waals (vdW) heterojunction is of particular interest as there is no overlap between the energy bands of its two stacked materials. Despite several studies on straddling-gap (type-I) and staggered-gap (type-II) vdW heterojunctions, a comprehensive understanding of the current-transport and optoelectronic effects in a type-III broken-gap heterojunction remains elusive. Here, we report gate-tunable current rectifying characteristics in a black phosphorus (BP)/rhenium disulfide (ReS2) broken-gap p-n heterojunction diode. Current-transport in this heterojunction was modeled by using the Simmons approximation through direct tunneling and Fowler?Nordheim tunneling in low- and higher-bias regimes, respectively. We showed that a p-n diode based on a type-III heterojunction is mainly governed by tunneling-mediated transport, but that transport in a type-I p-n heterojunction is dominated by majority carrier diffusion in the higher-bias regime. Upon illumination with a 532-nm-wavelength laser, the BP/ReS2 broken-gap p-n heterojunction showed a photo responsivity of 8 mA/W at a laser power as high as 100 μW and photovoltaic energy conversion with an external peak quantum efficiency of 0.3%. Finally, we demonstrated a binary inverter consisting of BP p-channel and ReS2 n-channel thin film transistors for logic applications.
关键词： Rhenium disulfide,photovoltaics,quantum tunneling,broken-gap heterojunction,logic circuitry,Black phosphorous
更新于2025-09-19 17:15:36
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Light-Driven Redox Activation of CO <sub/>2</sub> - and H <sub/>2</sub> -Activating Complexes in a Self-Assembled Triad
摘要： We report a self-assembled triad for artificial photosynthesis comprised of a chromophore, carbon-dioxide reduction catalyst, and hydrogen-oxidation complex, which is designed to operate without conventional sacrificial redox equivalents. Excitation of the zinc–tetraphenylporphyrin chromophore of the triad results in ultrafast charge transfer between a tungsten–alkylidyne donor and a rhenium diimine tricarbonyl acceptor, producing a charge-separated state that persists on the timescale of tens of nanoseconds and is thermodynamically capable of the primary dihydrogen and carbon dioxide binding steps for initiating the reverse water-gas shift reaction. The charge-transfer behavior of this system was probed using time-resolved fluorescence and transient absorption spectroscopy in the visible, near-infrared, and mid-infrared spectral regions. The behavior of the triad was compared to that of the zinc porphyrin–rhenium diimide dyad; the triad was found to have a significantly longer charge-separated lifetime than other previously reported porphyrin–rhenium diimine compounds.
关键词： artificial photosynthesis,zinc–tetraphenylporphyrin,charge transfer,reverse water-gas shift reaction,rhenium diimine tricarbonyl,self-assembled triad
更新于2025-09-12 10:27:22
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Dinitrogen Reduction to Ammonium at Rhenium Utilizing Light and Proton-Coupled Electron Transfer
摘要： The direct scission of the triple bond of dinitrogen (N2) by a metal complex is an alluring entry point into the transformation of N2 to ammonia (NH3) in molecular catalysis. Reported herein is a pincer-ligated rhenium system that reduces N2 to NH3 via a well-defined reaction sequence involving reductive formation of a bridging N2 complex, photolytic N2 splitting, and proton-coupled electron transfer (PCET) reduction of the metal-nitride bond. The new complex (PONOP)ReCl3 (PONOP = 2,6-bis(diisopropylphosphinito)pyridine) is reduced under N2 to afford the trans,trans-isomer of the bimetallic complex [(PONOP)ReCl2]2(μ-N2) as an isolable kinetic product that isomerizes sequentially upon heating into the trans,cis and cis,cis isomers. All isomers are inert to thermal N2 scission, and the trans,trans-isomer is also inert to photolytic N2 cleavage. In striking contrast, illumination of the trans,cis and cis,cis-isomers with blue light (405 nm) affords the octahedral nitride complex cis-(PONOP)Re(N)Cl2 in 47% spectroscopic yield and 11% quantum yield. The photon energy drives an N2 splitting reaction that is thermodynamically unfavorable under standard conditions, producing a nitrido complex that reacts with SmI2/H2O to produce a rhenium tetrahydride complex (38% yield) and furnish ammonia in 74% yield.
关键词： light,dinitrogen reduction,ammonium,proton-coupled electron transfer,rhenium
更新于2025-09-11 14:15:04
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Metal-Ligand Cooperative Synthesis of Benzonitrile via Electrochemical Reduction and Photolytic Splitting of Dinitrogen
摘要： Thermal nitrogen fixation relies on strong reductants to overcome the extraordinarily large N–N bond energy. Photochemical strategies that drive N2 fixation are scarcely developed. Here, the synthesis of a dinuclear N2-bridged complex is presented upon reduction of a rhenium(III) pincer platform. Photochemical splitting into terminal nitride complexes is triggered by visible light. Clean N-transfer with benzoyl chloride to free benzamide and benzonitrile is enabled by cooperative 2H+/2e– transfer of the pincer ligand. A three-step cycle is demonstrated for N2 to nitrile fixation that relies on electrochemical reduction, photochemical N2-splitting and thermal N-transfer.
关键词： Rhenium,Photochemistry,Electrochemistry,Nitrogen Fixation,Pincer Ligand
更新于2025-09-09 09:28:46
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Synthesis and Photophysical Properties of Rhenium(I)-Alkynyl Molecular Rectangles
摘要： A series of highly conjugated, rigid Re(I)-based molecular rectangles {[fac-Re(CO)3Br]2(μ-bpy) (μ-L)}2 (1, L = 1,4-bis(42 -pyridylethynyl)benzene, bpeb; 2, L = 1,4-bis(42 -pyridylethynyl)naphthalene, bpen; 3, L = 1,4-bis(42 -pyridylethynyl)anthracene, bpea; and bpy = 4,42 -bipyridine) containing two different types of pyridyl ligands were synthesized, characterized and their photophysical properties studied. Successful emission color tuning was achieved by incorporating rigid alkynyl ligands into the Re(I) rectangles. Complexes 1-3 exhibited an intense absorption bands with a high e value at > 340 nm in THF solution, which is attributed to mixed two metal-to-ligand charge transfer dp(Re) → p*(bpy) and dp(Re) → p*(alkynyl)) along with ligand-to-ligand charge transfer (1LLCT)/ and intraligand charge transfer (1ILCT) transitions. Compound 1 featured a broad and structureless emission band at 619 nm, which was attributed to the emission of 3MLCT dp(Re) → p*(bpy) and/or [dp(Re) → p*(alkynyl)] characteristics with an additional luminescence at 431 nm. Whereas complexes 2 and 3 displayed an intraligand (IL) emission at 445 and 489(sh), 521 nm. These compounds represent a new class of visible light-harvesting materials that exhibit greatly enhanced emission decay lifetimes as a result of intervening ligand triplet states (3LLCT/3ILCT) present on the alkynyl appended naphthalene and anthracene chromophores, as evidenced by transient absorption spectra.
关键词： rhenium,quenching,Rectangles,alkynyl ligands,luminescence
更新于2025-09-09 09:28:46