Photoinduced Charge Separation in Porphyrin Ion Pairs

Ion pairs between porphyrin-type compounds have been successfully employed for spectral sensitization of semiconductor surfaces and for the preparation of collective binary ionic materials for photonic and (photo)catalytic applications. The understanding of the photophysical processes occurring within ion-paired porphyrin dimers is thus of remarkable importance for the optimization and improvement of such systems. Herein the ion-pair species formed between ZnTMePyP4+ (Zn1) or H2TMePyP4+ (H21) and ZnTPPS4- (Zn2) or H2TPPS4- (H22) in a variety of solvent mixtures are characterized and their photophysics thoroughly investigated by time-resolved techniques. In all the systems studied, very fast and efficient photoinduced charge separation is observed, with the cationic porphyrin being reduced and the anionic one oxidized. Interestingly, despite the very short charge separation distance, the lifetime for charge recombination, depending on the energy gap, can extend into the nanosecond time domain, showing great potential for the utilization of this molecular design within energy conversion schemes.Ion pairs between porphyrin-type compounds have been successfully employed for spectral sensitization of semiconductor surfaces and for the preparation of collective binary ionic materials for photonic and (photo)catalytic applications. The understanding of the photophysical processes occurring within ion-paired porphyrin dimers is thus of remarkable importance for the optimization and improvement of such systems. Herein the ion-pair species formed between ZnTMePyP4+ (Zn1) or H2TMePyP4+ (H(2)1) and ZnTPPS4- (Zn2) or H2TPPS4-(H(2)2) in a variety of solvent mixtures are characterized and their photophysics thoroughly investigated by time-resolved techniques. In all the systems studied, very fast and efficient photoinduced charge separation is observed, with the cationic porphyrin being reduced and the anionic one oxidized. Interestingly, despite the very short charge separation distance, the lifetime for charge recombination, depending on the energy gap, can extend into the nanosecond time domain, showing great potential for the utilization of this molecular design within energy conversion schemes

Remarks on the Free Energy Correlation of Rate Constants for Electron Transfer Quenching of Electronically Excited States

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Excited-State Absorption of Tris(phenanthroline)rhodium(III). A Handle on the Excited-State Behavior of a Powerful Photochemical Oxidant

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METHOD OF PREPARATION OF MONONUCLEAR RUTHENIUM COMPLEXES

The invention refers to a process for the preparation of inorganic dyes, useful as spectral sensitizers for semiconductors, wherein the intermediate [Ru(dcb)2(C2O4)]4- is used

Verso la fotosintesi artificiale: competenze, strutture e progetti di ricerca nel settore

La fotosintesi artificiale, ovvero la conversione diretta di energia solare in energia chimica attraverso la sintesi fotoindotta di specie chimiche ad alta energia, quali idrogeno e altri combustibili, a partire da specie a bassa energia come acqua e anidride carbonica, un processo ispirato alla fotosintesi naturale, \ue8 stato per lungo tempo un sogno inseguito dalla comunit\ue0 scientifica internazionale. Gli sviluppi degli ultimi anni permettono adesso di affrontare il problema con buone speranze di successo. L\u2019articolo presenta una breve panoramica delle problematiche relative alla fotosintesi artificiale, delle strutture e dei progetti di ricerca nel settore attualmente presenti nei vari Paesi, con particolare attenzione per gli studi che vengono portati avanti dai ricercatori del SOLAR-CHEM, centro interuniversitario italiano per la conversione chimica dell\u2019energia solare

Tetrametallic molecular catalysts for photochemical water oxidation

Among molecular water oxidation catalysts (WOCs), those featuring a reactive set of four multi-redox transition metals can leverage an extraordinary interplay of electronic and structural properties. These are of particular interest, owing to their close structural, and possibly functional, relationship to the oxygen evolving complex of natural photosynthesis. In this review, special attention is given to two classes of tetrametallic molecular WOCs: (i) M4O4 cubane-type structures stabilized by simple organic ligands, and (ii) systems in which a tetranuclear metal core is stabilized by coordination of two polyoxometalate (POM) ligands. Recent work in this rapidly evolving field is reviewed, with particular emphasis on photocatalytic aspects. Special attention is given to studies addressing the mechanistic complexity of these systems, sometimes overlooked in the rush for oxygen evolving performance. The complementary role of molecular WOCs and their relationship with bulk oxides and heterogeneous catalysis are discusse