Phys Chem Chem Phys
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
Published: August 2022
Supramolecular cavities have been traditionally used to stabilize reactive redox intermediates. Recently with the success of multiple new photoredox catalytic strategies that use supramolecular cages, there is a growing demand for photogeneration strategies of diverse reactive intermediates inside confined spaces, which will drive enzyme-like catalysis in real time. Here we report the excited state dynamics of a redox-active TTF radical cation and its corresponding dimethyl-derivative DiMeTTF inside a confined supramolecular cavity. We prepare the radical cation by spontaneous oxidation of neutral TTF upon incarceration inside a water-soluble nanocage PdL, and characterize it with a combination of resonance Raman and electron paramagnetic resonance spectroscopy. Using broadband transient absorption spectroscopy, we demonstrate that the confined native TTF radical cation and its dimethyl derivative upon photoexcitation rapidly de-excite to form the hot ground state, thereby inhibiting further oxidation to a TTF dication. We discuss our results in the context of excited state crossings of the radical cation potentials as well as modifying the cage energetics to generate a stable dication. Our work has important implications for the usage of such radical cations for photoactivated catalysis.
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http://dx.doi.org/10.1039/d2cp01916g | DOI Listing |
Metal oxides are promising catalysts for small molecule hydrogen chemistries, mediated by interfacial proton-coupled electron transfer (PCET) processes. Engineering the mechanism of PCET has been shown to control the selectivity of reduced products, providing an additional route for improving reductive catalysis with metal oxides. In this work, we present kinetic resolution of the rate determining proton-transfer step of PCET to a titanium-doped POV, TiVO(OCH) with 9,10-dihydrophenazine by monitoring the loss of the cationic radical intermediate using stopped-flow analysis.
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January 2025
School of Science and Technology, Nottingham Trent University, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK.
This paper reports the synthesis, crystal structures and conducting properties of the first BEDT-TTF radical-cation salts with symmetry tris-coordinated racemic lanthanide(III) anions. It is also the first crystallographic determination of the nine-coordinate tris(chelidonato)terbate and tris(chelidonato)dysprosate anions (chelidonic acid = clo = 4-oxo-4-pyran-2,6-dicarboxylic acid). Salt α-(BEDT-TTF)M(chelidonato)·EtOH·2HO is semimetallic for M = Tb, and semiconducting for M = Dy.
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January 2025
Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India.
The work establishes the salt of a tetra-cationic distibane, [LSb][CFSO] = [][OTf] (CFSO = OTf), stabilized by a bis(α-iminopyridine) ligand , defying the Coulombic repulsion. The synthetic approach involved a dehydrocoupling reaction when a mixture of and Sb(OTf) in a 1:1 ratio was treated with EtSiH/LiBEtH as the hydride source. Compound [][OTf] was also achieved from [LSbCl][OTf] as a precursor and using EtSiH.
View Article and Find Full Text PDFJ Am Chem Soc
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Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
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Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
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