Prof. Ray erforscht die Katalyse von Oxidationsreaktionen durch Metallkomplexe, insbesondere die Kontrolle von Sauerstoff-Reduktion und Wasser-Oxidation mittels Übergangsmetallen (Eisen, Kobalt, Kupfer, Iridium). Seine aktuelle Arbeit konzentriert sich auf die Aufklärung von Reaktionsmechanismen auf molekularer Ebene — etwa wie man durch gezielte Liganden-Design steuert, ob Sauerstoff zu Wasserstoffperoxid oder Wasser reduziert wird, oder wie man Aldehyde oxidativ abbaut. Diese Erkenntnisse ermöglichen die Entwicklung effizienterer Katalysatoren für Energieumwandlung (Brennstoffzellen, Wasserspaltung) und Syntheseprozesse in der chemischen Industrie. Die Forschung ist relevant für Anwendungen in Energiespeicherung, Elektrokatalyse und nachhaltige Chemie-Synthesen.
🔒 Das System hat 631 mögliche Industrie-Partner gefunden — Firmen, Scores und Begründungen sind nur für eingeloggte Nutzer:innen sichtbar. Anmelden
Prof. Dr. Kallol Ray
HU-FIS-Profil ↗EXC 2008: Unifying Systems in Catalysis (UniSysCat)
university
EXC 2008: Unifying Systems in Catalysis (UniSysCat)
university
EXC 2008: Unifying Systems in Catalysis (UniSysCat)
other
Förderer: DFG Exzellenzinitiative Cluster Zeitraum: 11/2007 - 10/2012 Projektleitung: Prof. Dr. Kallol Ray
Förderer: DFG Exzellenzinitiative Cluster Zeitraum: 11/2012 - 10/2017 Projektleitung: Prof. Dr. Kallol Ray
Förderer: DFG Sachbeihilfe Zeitraum: 07/2015 - 06/2018 Projektleitung: Prof. Dr. Kallol Ray
Nature Communications · DOI
Journal of the American Chemical Society · DOI
Selective functionalization of unactivated C-H bonds, water oxidation, and dioxygen reduction are extremely important reactions in the context of finding energy carriers and conversion processes that are alternatives to the current fossil-based oil for energy. A range of metalloenzymes achieve these challenging tasks in biology by using cheap and abundant transition metals, such as iron, copper, and manganese. High-valent metal-oxo and metal-dioxygen (superoxo, peroxo, and hydroperoxo) cores act as active intermediates in many of these processes. The generation of well-described model compounds can provide vital insights into the mechanisms of such enzymatic reactions. This perspective provides a focused rather than comprehensive review of the recent advances in the chemistry of biomimetic high-valent metal-oxo and metal-dioxygen complexes, which can be related to our understanding of the biological systems.
Proceedings of the National Academy of Sciences
The reactivities of mononuclear nonheme iron(IV)-oxo complexes bearing different axial ligands, [Fe(IV)(O)(TMC)(X)](n+) [where TMC is 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane and X is NCCH(3) (1-NCCH(3)), CF(3)COO(-) (1-OOCCF(3)), or N(3)(-) (1-N(3))], and [Fe(IV)(O)(TMCS)](+) (1'-SR) (where TMCS is 1-mercaptoethyl-4,8,11-trimethyl-1,4,8,11-tetraazacyclotetradecane), have been investigated with respect to oxo-transfer to PPh(3) and hydrogen atom abstraction from phenol O H and alkylaromatic C H bonds. These reactivities were significantly affected by the identity of the axial ligands, but the reactivity trends differed markedly. In the oxidation of PPh(3), the reactivity order of 1-NCCH(3) > 1-OOCCF(3) > 1-N(3) > 1'-SR was observed, reflecting a decrease in the electrophilicity of iron(IV)-oxo unit upon replacement of CH(3)CN with an anionic axial ligand. Surprisingly, the reactivity order was inverted in the oxidation of alkylaromatic C H and phenol O H bonds, i.e., 1'-SR > 1-N(3) > 1-OOCCF(3) > 1-NCCH(3). Furthermore, a good correlation was observed between the reactivities of iron(IV)-oxo species in H atom abstraction reactions and their reduction potentials, E(p,c), with the most reactive 1'-SR complex exhibiting the lowest potential. In other words, the more electron-donating the axial ligand is, the more reactive the iron(IV)-oxo species becomes in H atom abstraction. Quantum mechanical calculations show that a two-state reactivity model applies to this series of complexes, in which a triplet ground state and a nearby quintet excited-state both contribute to the reactivity of the complexes. The inverted reactivity order in H atom abstraction can be rationalized by a decreased triplet-quintet gap with the more electron-donating axial ligand, which increases the contribution of the much more reactive quintet state and enhances the overall reactivity.