A5042151375- Photochemistry and Electron Transfer Studies
- Photochromic and Fluorescence Chemistry
- Radical Photochemical Reactions
- bioluminescence and chemiluminescence research
- Spectroscopy and Chemometric Analyses
- Photodynamic Therapy Research Studies
- Advanced Chemical Sensor Technologies
- Porphyrin and Phthalocyanine Chemistry
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Edible Oils Quality and Analysis
- Luminescence and Fluorescent Materials
- Light effects on plants
- Cultural Heritage Materials Analysis
- Fermentation and Sensory Analysis
- TiO2 Photocatalysis and Solar Cells
- Analytical Chemistry and Chromatography
- Spectroscopy and Quantum Chemical Studies
- Analytical Chemistry and Sensors
- Nanoplatforms for cancer theranostics
- Oxidative Organic Chemistry Reactions
- Advanced Photocatalysis Techniques
- Lignin and Wood Chemistry
- Botanical Research and Applications
- Chemical Synthesis and Reactions
Adam Mickiewicz University in Poznań
2015-2024
Northwest Normal University
2023
Faculty (United Kingdom)
2015-2018
University of Algarve
2004-2007
Instituto Superior Técnico
2005-2006
BioInfoBank Institute
2005-2006
Loughborough University
1997-2004
University of Notre Dame
1999
University of Saskatchewan
1998
Photostability studies of drugs and drug products are an integral part the product development process in pharmaceutical industry. These carried out to ensure quality, efficacy, safety formulated during manufacture, storage, use. This review deals with concept photostability related aspects literature available field. It highlights role photochemistry studies, describes functional groups important for photoreactivity drugs, explains photophysical processes, kinetics photochemical reactions....
Abstract We have developed a metal‐free process for the aerobic photooxygenation of sulfides to sulfoxides mediated by riboflavin tetraacetate or (vitamin B 2 ) photocatalysts and visible light (450 nm) in an acetonitrile‐water (85:15 v/v) mixture. The optimised solvent system leads both singlet‐oxygen electron‐transfer pathways photooxygenation, thus allowing oxidation electron‐poor electron‐rich thioanisoles, dialkyl sterically hindered sulfides. Besides having broad substrate scope,...
Chemoselective photooxidation: Tetra-O-acetylriboflavin and blue light mediate the selective oxidation of sulfides to sulfoxides without overoxidation sulfones. Reaction is very effective in ethanol/water (95:5,v/v) mixture reaching a quantum yield Φ=0.60. The photooxidation reaction scope includes aliphatic aromatic including sterically hindered substrates. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not...
We report a system with ethylene-bridged flavinium salt 2b which catalyzes the aerobic oxidation of toluenes and benzyl alcohols high potential (Eox > +2.5 V vs SCE) to give corresponding benzoic acids under visible light irradiation. This is caused by oxidizing power excited (E(2b*) = +2.67 involved in photooxidation accompanying dark organocatalytic oxygenation provided situ formed flavin hydroperoxide 2b-OOH.
Solvent effects on the spectroscopic properties of lumichromes and lumiflavins are presented. Fluorescence yields for an order magnitude larger than those lumichromes, due to their lower nonradiative rate constants. absorption emission band positions explained basis hydrogen-bonding interactions. TD-DFT calculations predicted that lowest energy states n,π* in case but π,π* lumiflavins. The overall consistency singlet−singlet triplet−triplet transitions obtained various compounds studied,...
To study luminescence, reflectance, and color stability of dental composites ceramics.IPS e.max, IPS Classic, Gradia, Sinfony materials were tested, both unpolished (as-cast) polished specimens. Coffee, tea, red wine, distilled water (control) used as staining drinks. Disk-shaped specimens soaked in the drinks for up to 5 days. Color was measured by a colorimeter. Fluorescence recorded using spectrofluorometer, front-face geometry. Time-resolved fluorescence spectra laser nanosecond...
Summary The present study demonstrates the use of fluorescence spectroscopy for monitoring changes in virgin olive oil during storage. Total luminescence and synchronous scanning techniques were tested with purpose to check their ability monitor occurring storage different conditions: clear green glass bottles exposed light, darkness. spectra initial samples n ‐hexane solutions exhibited intense peaks, one a maximum appearing at 320 nm emission 290 excitation, attributed tocopherols, another...
Low-charged tungsten ions are essential for edge plasma diagnostics in large fusion devices, but their study has been limited due to the complex electronic structure associated with open 4f orbitals. In this work, we investigate visible spectrum emission of W9+ion obtained by electron beam ion trap (EBIT) device, energy set below ionization threshold W8+ ions. Transition wavelengths and partial levels W9+ were calculated using Dirac-Fock-Slater (DFS) method, showing strong agreement...
Transient UV-vis-NIR absorption of betanin in water.
Some spectroscopic properties of alloxazines and the lifetimes their singlet triplet states in acetonitrile are reported. In addition, efficiencies oxygen production by energy transfer from excited a range substituted lumiflavine have been determined aerated solution. Triplet state quantum yields also measured it has shown that efficiency is equal to unity within experimental error all cases.
The study demonstrates the application of front face and right angle synchronous fluorescence spectroscopy for characterization edible oils. method enables monitoring tocopherols, pheophytins, other fluorescent components in Principal component analysis spectra revealed sample clustering according to type oil. Partial least-squares regression was utilized develop calibration models between total tocopherol content determined by HPLC. showed a good ability predict content. best fitting...
Light-induced degradation of the riboflavin derivatives is reported, including 5-deaza-riboflavin, iso-6,7-riboflavin, 3-methyl-tetra-acetyl-riboflavin (3MeTARF), and 3-benzyl-lumiflavin. The studied compounds undergo photolytic processes with considerable quantum yields in methanolic solutions (φ ≈ 10–3–10–4 mol einst–1). Photolysis anaerobic conditions more efficient than that presence oxygen. Experiments show triplet excited state flavin molecules involved reactions. main photoproducts...
Lumichrome photophysical properties at different pH were characterized by UV-vis spectroscopy and steady-state time-resolved fluorescence techniques, in four forms of protonation/deprotonation: neutral form, two monoanions, dianion. The excited-state lifetimes these lumichrome measured discussed. results compared to those obtained for similar alloxazine and/or isoalloxazine, also 1-methyl- 3-methyllumichrome 1,3-dimethyllumichrome. absorption, emission, synchronous spectra lumichrome,...