[reaction: see text] We have synthesized novel spiro-bridged chromophores incorporating a 4,5-diazafluorene unit as the electron acceptor (A) and aryl amino groups as donor (D) moieties. The orthogonal D-A configuration limits ground-state D-A interactions but allows efficient PET reactions. The PET efficiency was modulated by the electronic characteristics of the donor and by the D-A distance. Preliminary studies showed that the PET process can be manipulated through metal ion complexation of the 4,5-diazafluorene moiety.
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http://dx.doi.org/10.1021/ol061227n | DOI Listing |
Nanoscale
January 2025
Centre for Nano Science and Nano Technology, S 'O' A (Deemed to be University), Bhubaneswar-751 030, Odisha, India.
Titanium (Ti)-based MOFs are promising materials known for their porosity, stability, diverse valence states, and a lower conduction band (CB) than Zr-MOFs. These features support stable ligand-to-metal charge transfer (LMCT) transitions under photoirradiation, enhancing photocatalytic performance. However, Ti-MOF structures remain a challenge owing to the highly volatile and hydrophilic nature of ionic Ti precursors.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
Chromophores incorporated into rigid polymer matrices may exhibit novel photophysical properties distinct from those in liquid solutions. In this work, we explored the decay path of the second ππ* state (2ππ*) of riboflavin in poly(vinyl alcohol) (PVA) solutions and films with various acidities. Highly efficient internal conversion from 2ππ* to the lowest ππ* state (1ππ*) induced by slight in-plane motion is demonstrated in all PVA solutions and films, irrespective of environmental acidity and rigidification.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States.
Green fluorescent protein (GFP) chromophores are widely studied as fluorescent moieties for sensing and imaging applications. Herein, we present a straightforward synthetic strategy that involves the reaction of glycine amides with 1,3-diketones to form imidazolones through an unusual molecular fragmentation and recombination pathway. Mechanistic investigations, including crossover experiments, inspired a competing strategy that incorporates exogenous ketones into the products, yielding fluorescent GFP chromophore analogues.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Departament de Farmàcia i Tecnologia Farmacèutica, i Fisicoquímica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), 08028 Barcelona, Spain.
Incorporation of environment and vibronic effects in simulations of optical spectra and excited state dynamics is commonly done by combining molecular dynamics with excited state calculations, which allows to estimate the spectral density describing the frequency-dependent system-bath coupling strength. The need for efficient sampling, however, usually leads to the adoption of classical force fields despite well-known inaccuracies due to the mismatch with the excited state method. Here, we present a multiscale strategy that overcomes this limitation by combining EMLE simulations based on electrostatically embedded ML potentials with the QM/MMPol polarizable embedding model to compute the excited states and spectral density of 3-methyl-indole, the chromophoric moiety of tryptophan that mediates a variety of important biological functions, in the gas phase, in water solution, and in the human serum albumin protein.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
MOE Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, China.
Immobilizing organic chromophores within the rigid framework of metal-organic frameworks (MOFs) augments fluorescence by effectively curtailing molecular motions. Yet, the substantial interspaces and free volumes inherent to MOFs can undermine photoluminescence efficiency, as they partially constrain intramolecular dynamics. In this study, we achieved optimization of both one- and two-photon excited fluorescence by incorporating linkers into an interpenetrated tetraphenylethene-based MOF (TPE-MOF).
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