This work assessed solvent isotope effects on the photoracemization rate and emission lifetime for [Ru(bpy)3]2+ (bpy = 2,2'-bipyridine) in water. An analysis of the effects of temperature on photoracemization rate and emission lifetime demonstrated that the transition from one enantiomer to the other is unaffected by the isotopic composition of the solvent. The results also showed that deactivation from the metal-to-ligand charge-transfer (3MLCT) excited state to the ground state is responsible for the solvent isotope effect on the photoracemization rate. The photoracemization reaction was found to proceed via a bond-breaking mechanism. In this process, a five-coordinated species produced through breaking of the Ru-N bond in the 3d-d* state undergoes a structural change to produce an achiral five-coordinated species. An analysis of the effect of temperature on emission lifetime, excluding the activation to the 3d-d* state that leads to the structural change, showed that the solvent isotopic composition affects deactivation from the 4th MLCT state.
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http://dx.doi.org/10.1039/c9cp06758b | DOI Listing |
Nat Commun
January 2025
University of St Andrews, School of Biology, North Haugh, Biomolecular Sciences Building, St Andrews, UK.
Cyclic dipeptides are produced by organisms across all domains of life, with many exhibiting anticancer and antimicrobial properties. Oxidations are often key to their biological activities, particularly C-C bond oxidation catalysed by tailoring enzymes including cyclodipeptide oxidases. These flavin-dependent enzymes are underexplored due to their intricate three-dimensional arrangement involving multiple copies of two distinct small subunits, and mechanistic details underlying substrate selection and catalysis are lacking.
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January 2025
State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University 800 Dongchuan Road, Shanghai, P. R. China.
Reactive oxygen species with evoked immunotherapy holds tremendous promise for cancer treatment but has limitations due to its dependence on exogenous excitation and/or endogenous HO and O. Here we report a versatile oxidizing pentavalent bismuth(V) nanoplatform (NaBiO-PEG) can generate reactive oxygen species in an excitation-free and HO- and O-independent manner. Upon exposure to the tumor microenvironment, NaBiO-PEG undergoes continuous H-accelerated hydrolysis with •OH and O generation through electron transfer-mediated Bi-to-Bi conversion and lattice oxygen transformation.
View Article and Find Full Text PDFChemistry
January 2025
Indian Institute of Science Education and Research Bhopal Department of Chemistry, Chemistry, Room No. 226, Academic Block - 2, Indore By-pass Road, Bhauri, 462066, Bhopal, INDIA.
Unraveling the electronic structure of metal complexes can bring various catalytic possibilities for hydrogen evolution reaction (HER). However, the electronic effect of metal and ligands modulating and switching the reaction center for HER has yet to be comprehensively analyzed. Herein, we report nickel selenoether electrocatalysts which show tunable reaction centers (nickel or ligand) for HER using mild weak acetic acid in less deprotonating DMF solvent.
View Article and Find Full Text PDFSci Rep
January 2025
Institute for Breath Research, University of Innsbruck, Innrain 80/82, Innsbruck, 6020, Austria.
Cytochrome P450 (CYP) 3A4 plays a major role in drug metabolism. Its activity could be determined by non-invasive and cost-effective assays, such as breath analysis, for the personalised monitoring of drug response. For the first time, we identify an isotopically unlabelled CYP3A4 substrate, tolterodine that leads to the formation of a non-toxic volatile metabolite, acetone, which could potentially be applied to monitor CYP3A4 activity in humans.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Universitat Bern, Department of Chemistry and Biochemistry, Freiestrasse 3, 3012, Bern, SWITZERLAND.
Isotope Exchange processes are becoming the preferred way to prepare isotopically labelled molecules, avoiding the redesign of multistep synthetic protocols. In the case of deuterium incorporation, the most used strategy has employed transition metals, that offer high reactivity under mild reaction conditions. Despite their success, the trade-off is that these metals are precious, and often exhibit high toxicity.
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