The influence of an electron donating substituent on the photophysical properties of 1-azathioxanthone dyes has been investigated using optical spectroscopy and theoretical models. The motivation behind the study is based on the fact that thioxanthones are efficient triplet sensitizers, and thus promising sensitizers for lanthanide centered emission. By adding an aza group to one of the phenyl ring systems, direct coordination to a lanthanide center becomes possible, which makes azathoixanthones great candidates as antenna chromophores in lanthanide(III) based dyes. Here, three 1-azathioxanthone derivatives have been synthesized targeting efficient triplet formation following absorption in the visible range of the spectrum. This is achieved by adding methoxy groups to the 1-azathioxanthone core. The derivatives were characterized using absorption, emission, and time-gated emission spectroscopy, where fluorescent quantum yields, singlet and triplet excited states lifetimes were determined. The experimentally determined photophysical properties of the three 1-azathioxanthone compounds are contrasted to those of the parent thioxanthone and is rationalized using the Strickler-Berg equation, Hückel MO theory, and Dewar's rules in combination with computational chemistry. We find that the transition energies follow predictions, but that the overall photophysical properties are determined by the relative energies as well as the nature of the involved states in both the singlet and the triplet excited state manifolds.
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http://dx.doi.org/10.1088/2050-6120/aa9c16 | DOI Listing |
J Biomol Struct Dyn
January 2025
Department of Chemistry, National Institute of Technology Silchar, Silchar, Assam, India.
A series of 2,6-di(pyrazine-2-yl)pyridine (dppy) ligands - of varying substituents of different electronic nature (-NMe, -OMe,-Me, and -Cl) in the 4-position of the pyridine moiety has been designed and synthesized to study the binding behavior of the dppy ligands towards Bovine Serum Albumin (BSA), a low-cost serum albumin protein. The interaction between ligands and BSA has been studied using UV-Visible and fluorescence spectroscopy and molecular docking studies. The fluorescence of BSA was found to be quenched in the presence of all the ligands , in which ligand , having the most electron donating group NMe exhibits the maximum binding affinity towards BSA.
View Article and Find Full Text PDFChemistry
January 2025
The Hong Kong Polytechnic University, Department of Applied Biology and Chemical Technology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Hom, Hong Kong (P.R. China), 000000, Hong Kong, HONG KONG.
A series of new (donor)₂-donor-π-acceptor (D2-D-π-A) and (acceptor)₂-donor-π-acceptor (A2-D-π-A) organic photosensitizers based on the framework of (Z)-2-cyano-3-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)acrylic acid have been synthesized and characterized. By incorporating groups with different electron-donating or withdrawing abilities, such as dibenzothiophene (DBT), dibenzofuran (DBF), and triazine (TA), into the triphenylamine segment, their photophysical properties have been regulated. Theoretical calculations were used to explore how various donor-acceptor combinations influence their hydrogen production performance.
View Article and Find Full Text PDFBioorg Med Chem
January 2025
School of Pharmacy, Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Guizhou International Science & Technology Cooperation Base of Medical Optical Theranostics Research, Zunyi Medical University, Zunyi, Guizhou 563003, PR China. Electronic address:
A series of aggregation-induced emission luminogens (AIEgens) with donor-π-acceptor (D-π-A) architecture were rationally designed and synthesized through π-bridge engineering for dual-modal photodynamic and photothermal therapy. The AIEgens (TPT, TFT, and TTT) were constructed using methoxy-substituted tetraphenylene as the electron donor and tricyanofuran as the electron acceptor, connected via different π-bridges (phenyl, furan, or thiophene). These compounds exhibited red-shifted absorption (460-545 nm) and emission (712-720 nm) with remarkable aggregation-induced emission characteristics.
View Article and Find Full Text PDFBiomater Sci
January 2025
School of Chemistry and Life Sciences, Hanoi University of Science and Technology, 1 Dai Co Viet Road, Ha Noi, Vietnam.
With the advancement of photodynamic therapy, various photosensitizers have been developed to enhance the efficacy of cancer treatment while minimizing side effects. Recently, near-infrared organic fluorophores have gained significant attention as promising photodynamic agents for cancer therapy due to their tunable photophysical properties, structural versatility, good biocompatibility, high biosafety, and synthetic flexibility. In particular, near-infrared organic photosensitizers offer several notable advantages, including deep tissue penetration, a low fluorescence background for bioimaging, and reduced damage to biological tissues compared to traditional visible-spectrum photosensitizers.
View Article and Find Full Text PDFChemistry
January 2025
Institute of Chemical Technology, Mumbai, Department of Dyestuff Technology, Nathelal parekh Marg, 400019, India, 400019, Matunga, 2010, INDIA.
Mechanochromic materials, known for their ability to change color in response to mechanical stimuli such as pressure, stretching, grinding, or rubbing, hold significant importance due to their diverse applications. In this study, we synthesized and characterized two novel pyridine-tethered imidazo[1,2-a]pyridine mechanoresponsive luminogens with appended tetraphenylethene, named GBY-10 and GBY-11. GBY-10 exhibited reversible mechanofluorochromism, while GBY-11 did not revert to its original color after solvent fuming.
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