The binuclear complex [RuII(NH3)5(pz)RuII(bpy)2(NO)](PF6)5 was prepared and characterized by elemental analysis, UV-vis, and IR spectroscopy. The complex UV-vis spectrum has presented bands at 242, 286, and 530 nm in acetate buffer solution at pH 4.5. The photochemical study by laser flash-photolysis at 532 nm showed the NO release account from the NO measured by a NO sensor. The quantum yield for NO release (0.025 +/- 0.004 mol einsten-1) was determined with a laser flash-photolysis apparatus (Continuum Q-switched Nd:YAG laser). The major irradiation product of the [RuII(NH3)5(pz)RuII(bpy)2(NO)]5+ complex besides nitric oxide is [RuIII(NH3)5(pz)RuII(bpy)2(H2O)]5+.
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http://dx.doi.org/10.1021/ja0376801 | DOI Listing |
J Phys Chem B
January 2025
Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland.
In the course of 266 nm nanosecond laser flash photolysis of carbazole (CBL) in acetonitrile, we discovered a new transient absorption band centered at 360 nm that has been heretofore unreported despite numerous reports on similar topics. To put some limits on possible transients responsible for this absorption band and thus to solve the mechanism of CBL photolysis, we employed the strategy of selectively blocking the CBL active sites by various modifications in the structure. This strategy was supported by the use of the solvent effect and triplet quenching by molecular oxygen.
View Article and Find Full Text PDFChemphyschem
January 2025
Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue-Straße 7, 60438, Frankfurt, Germany.
The light-sensing activity of phytochromes is based on the reversible light-induced switching between two isomerization states of the bilin chromophore. These photo-transformations may not necessarily be only unidirectional, but could potentially branch back to the initial ground state in a thermally driven process termed shunt. Such shunts have been rarely reported, and thus our understanding of this process and its governing factors are limited.
View Article and Find Full Text PDFMacromol Rapid Commun
December 2024
Paris-Est Creteil University, CNRS, ICMPE, UMR 7182, Thiais, 94320, France.
The design of a new visible-light methacrylated-based kraft lignin photosensitizer (MAcL) of iodonium salt (Iod) for the free-radical polymerization (FRP) of polyethylene glycol dimethacrylate (PEGDMA) under LEDs@405, 455, 470, 505, and 530 nm is reported. As demonstrated by laser flash photolysis (LFP) and electron paramagnetic resonance spin-trapping (EPR ST) experiments, the combination of MAcL with an electron acceptor (Iod) and trimethylolpropane tris(3-mercaptopropionate) (TT) used as a crosslinker, leads to the formation of highly efficient initiating radicals, i.e.
View Article and Find Full Text PDFPhotochem Photobiol Sci
December 2024
Instituto Universitario Mixto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Avda de los Naranjos s/n, 46022, Valencia, Spain.
Photophysical and photochemical studies were carried out to examine the photoreactivity of etheno adducts, 1,N-ethenoadenine (εdA) and 1,N-ethenoguanine (εdG), in the presence of two well-known photosensitizers acting by Type I and/or Type II mechanisms such as 4-carboxybenzophenone (CBP) and rose Bengal (RB), respectively. Steady-state photolysis experiments combined with HPLC and mass spectroscopy measurements lead to photoproducts that correspond to the repaired nucleosides. To determine the mechanism of this photooxidation processes, phosphorescence spectroscopy, direct detection of singlet oxygen luminescence and laser flash photolysis were carried out.
View Article and Find Full Text PDFChemistry
December 2024
Instituto de Tecnología Química, Universitat Politècnica de València - Agencia Estatal Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, 46022, Valencia, Spain.
An intrinsic metal cluster NIR-II emission of the {TaBr} aqua/hydroxocomplexes was determined in aqueous solutions under inert atmosphere. The photoluminescence (PL) is enhanced in DO, and the lifetime scale expands from nanoseconds to microseconds. Possible cluster emission transitions have been assigned and analyzed from a computational perspective.
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