In this work, we investigated for the first time morin in MeOH at different pH values by picosecond time-resolved fluorescence. We identified the two species responsible for the fluorescence at low and high pH. The solvated morin-solvent hydrogen-bonded complex has been experimentally observed for the first time. We give also the typical fluorescence spectra as well as the fluorescence lifetimes of the probable emitting species. In this work we put forward new insights concerning the contribution of free morin to the fluorescence. We hope that these new data improve the accuracy of the interpretation of the cation:morin complexes titration using fluorescence signal.
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http://dx.doi.org/10.1002/cphc.202000608 | DOI Listing |
Sci Adv
January 2025
Department of Chemistry, Brown University, Providence, RI, USA.
Disulfide bonds are ubiquitous molecular motifs that influence the tertiary structure and biological functions of many proteins. Yet, it is well known that the disulfide bond is photolabile when exposed to ultraviolet C (UVC) radiation. The deep-UV-induced S─S bond fragmentation kinetics on very fast timescales are especially pivotal to fully understand the photostability and photodamage repair mechanisms in proteins.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada.
The ability to manipulate excited-state decay cascades using molecular structure is essential to the application of abundant-metal photosensitizers and chromophores. Ligand design has yielded some spectacular results elongating charge-transfer excited state lifetimes of Fe(II) coordination complexes, but triplet metal-centered (MC) excited states─recently demonstrated to be critical to the photoactivity of isoelectronic Co(III) polypyridyls─have to date remained elusive, with temporally isolable examples limited to the picosecond regime. With this report, we show how strong-field donors and intramolecular π-stacking can conspire to stabilize a long-lived MC excited state for a remarkable 4.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan.
[Pt(NCN)MeCN] (NCN = 1,3-di(2-pyridyl)benzene, MeCN = acetonitrile) forms oligomers in the ground state due to metallophilic interactions, and a Pt-Pt bond is formed with photoexcitation. Ultrafast excited-state dynamics of the [Pt(NCN)MeCN] dimer in acetonitrile is investigated by femtosecond time-resolved absorption (TA) and picosecond emission spectroscopy. The femtosecond TA signals exhibit 60 cm oscillations arising from the Pt-Pt stretching motion in the S dimer.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea.
A photodetachment and photoelectron spectroscopic study by employing a cryogenically cooled ion trap combined with a velocity-map imaging setup has been carried out to unravel the vibrational structures and autodetachment dynamics of the dipole-bound states (DBSs) of -, -, and -methylphenolate anions (-, -, and -CHPhO). The electron binding energy of the DBS increases monotonically with the increase of the neutral dipole moment to give respective values of 66 ± 15, 123 ± 18, or 154 ± 14 cm for the -, -, or -isomer. The different electron-donating effects of the methyl moieties in the three geometrically different isomers seem to be reflected in the experiment.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Laser Research Center, Vilnius University, Saulėtekio av. 10, LT-10223, Lithuania.
Pyrano[2,3-]pyrazole derivatives are a class of compounds exhibiting dual solvent-dependent fluorescence. This interesting and potentially useful optical property is attributed to the excited state intramolecular proton transfer (ESIPT). We have investigated excited state dynamics of these molecules in detail using femtosecond time-resolved fluorescence and transient absorption spectroscopy.
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