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A Noble-Metal-Free Heterogeneous Photosensitizer-Relay-Catalyst Triad Catalyzes Water Oxidation under Visible Light
摘要： An entirely earth abundant chromophore-relay-water oxidation catalyst triad system, which is robust and efficient at neutral pH, is presented. The synthesis involves the coordination of a porphyrin derivative to a bridging Fe(CN)5 group, which is then reacted with Co ions to prepare a covalently linked chromophore-Prussian blue analogue assembly. Light driven water oxidation studies in the presence of an electron scavenger indicate that the triad is active and it maintains a steady activity for at least 3 hours. Transient absorption experiments and computational studies reveal that the Fe(CN)5 group is more than a linker as it takes part in electron-transfer and co-operates with porphyrin in the charge separation process.
关键词： water splitting,triad,dye-sensitized,water oxidation,Prussian blue,porphyrin
更新于2025-09-23 15:21:01
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Synthesis and properties of a novel porphyrin–fullerene triad assembled through donor–acceptor bonding
摘要： Complexation of (hydroxy)(oxo)(5,10,15,20-tetraphenylporphyrinato) molybdenum(v) with 2',5'-di(2-pyridyl)-1'-(3-pyridyl methyl)pyrrolidino[70]fullerene leading to a new donor–acceptor triad is characterized by quantitative description of the equilibrium and the reaction rate. The prospects of the triad as a photosynthetic antenna imitator and an active layer in solar energy conversion devices are substantiated.
关键词： solar energy conversion,porphyrin–fullerene triad,donor–acceptor bonding,photosynthesis
更新于2025-09-16 10:30:52
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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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Surface triads with optical properties
摘要： A geometric model of formation of surfaces comprising an interconnected triple of emitter, reflector and receiver is presented in the paper. The model is based on cyclographic mapping of a spatial curve to the plane. In such map any given point (x, y, z) of the curve corresponds to a cycle with center (x, y) and radius equal to z applicate. The entire curve corresponds to a directed envelope of cycles consisting, in the general case, of two branches. It is shown that the triad of curves consisting of two branches of the envelope and the orthogonal projection of the original curve within the plane (xy) corresponds to a triad of developable surfaces. The triad of curves in the plane (xy) and the original curve together form a triad of ruled surfaces. Both triads have an optical property. Any ray of light emerging from the point of the emitter surface along the normal to it and falling on the surface of the reflector afterwards is directed along the normal vector to the surface of the receiver. The direct and inverse problems of formation of the triad of surfaces are solved. In the first case, a one-parameter set of triads of surfaces is defined from a given spatial curve. In the second case, a single triad of surfaces is defined from a pair of curves "emitter-receiver" defined on the plane (xy). Numerical examples of solutions of the direct and inverse problems are considered and the corresponding visualizations are given. The results of the work can be used in the design of reflector antennas in radar systems and systems for converting solar energy into electric and thermal energy.
关键词： triad of surfaces,optical property,cyclographic mapping,geometric model
更新于2025-09-10 09:29:36
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High-Energy Charge-Separated States by Reductive Electron Transfer Followed by Electron Shift in Tetraphenylethylene – Aluminum(III) Porphyrin – Fullerene Triad
摘要： A high potential supramolecular triad (TPE-AlPor?Im-C60) composed of aluminum(III) porphyrin (AlPor), fullerene (C60), and tetraphenylethylene (TPE) has been constructed. The fullerene and tetraphenylethylene units are bound axially to opposite faces of the porphyrin plane via coordination and covalent bonds, respectively. The ground and excited-state properties of the triad and reference dyads are studied using steady-state and time-resolved spectroscopic techniques. The transient data show that photoexcitation results in charge separation (CS) from tetraphenylethylene to the excited singlet state of the porphyrin (1AlPor*), generating high-energy (2.14 eV) charge-separated state, (TPE)?+-(AlPor)?? in toluene. A subsequent electron migration from the AlPor?? to fullerene generates a second high-energy (1.78 eV) charge-separated state (TPE)?+-AlPor?Im-(C60)??. The lifetime of the charge separation persists about 25 ns. The high energy stored in the form of charge-separated states along with its reasonable lifetimes makes these donor-acceptor systems potential electron-transporting catalysts to carry out energy-demanding photochemical reactions, especially in artificial photosynthesis for conversion of solar energy into chemical energy.
关键词： high-energy charge-separated states,aluminum(III) porphyrin,tetraphenylethylene,fullerene,reductive electron transfer,electron shift,triad
更新于2025-09-09 09:28:46