Herein, two new quadrupolar acceptor-π-donor-π-acceptor (A-π-D-π-A) chromophores have been prepared featuring a strongly electron-donating diborene core and strongly electron-accepting dimesitylboryl (BMes ) and bis(2,4,6-tris(trifluoromethyl)phenyl)boryl (B Mes ) end groups. Analysis of the compounds by NMR spectroscopy, X-ray crystallography, cyclic voltammetry, and UV/Vis-NIR absorption and emission spectroscopy indicated that the compounds have extended conjugated π-systems spanning their B C cores. The combination of exceptionally potent π-donor (diborene) and π-acceptor (diarylboryl) groups, both based on trigonal boron, leads to very small HOMO-LUMO gaps, resulting in strong absorption in the near-IR region with maxima in THF at 840 and 1092 nm and very high extinction coefficients of ca. 120 000 m cm . Both molecules also display weak near-IR fluorescence with small Stokes shifts.
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http://dx.doi.org/10.1002/anie.201900889 | DOI Listing |
Chem Sci
October 2024
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku Kyoto 615-8510 Japan
Since π-conjugated molecules are commonly used as a scaffold for constructing optoelectronic and functional materials, much effort has been devoted to exploring novel molecular scaffolds for obtaining superior properties. This study focuses on dinuclear hypervalent tin(iv) compounds prepared by the ladderization of Schiff bases using hypervalent tin units. The optical measurements found that introducing hypervalent tin atoms can reinforce the D-π-A system.
View Article and Find Full Text PDFChemistry
September 2024
Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33400, Talence, France.
"Tandem" uncaging systems, in which a photolabile protecting group (PPG) is sensitized by an energy-harvesting antenna, may increase the photosensitivity of PPGs by several orders of magnitude for two-photon (2P) photorelease. Yet, they remain poorly accessible because of arduous multi-step synthesis. In this work, we design efficient tandem uncaging systems by (i) using a convenient assembly of the building blocks relying on click chemistry, (ii) introducing H-bonding induced proximity thus facilitating (iii) photoinduced electron transfer (PeT) as a cooperative mechanism.
View Article and Find Full Text PDFJ Am Chem Soc
September 2023
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
More than a decade of research on the photoluminescence (PL) of classic Au(SR) and its doped nanoclusters (NCs) still leaves many fundamental questions unanswered due to the complex electron dynamics. Here, we revisit the homogold Au (ligands omitted hereafter) and doped NCs, as well as the Ag and doped ones, for a comparative study to disentangle the influencing factors and elucidate the PL mechanism. We find that the strong electron-vibration coupling in Au leads to weak PL in the near-infrared region (∼1000 nm, quantum yield QY = 1% in solution at room temperature).
View Article and Find Full Text PDFMolecules
March 2022
Départment Sciences de la Matière et du Rayonnement, Université Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33400 Talence, France.
Molecular-based Fluorescent Organic Nanoparticles (FONs) are versatile light-emitting nano-tools whose properties can be rationally addressed by bottom-up molecular engineering. A challenging property to gain control over is the interaction of the FONs' surface with biological systems. Indeed, most types of nanoparticles tend to interact with biological membranes.
View Article and Find Full Text PDFCommun Chem
October 2021
Centro de Química Estrutural (CQE) and Institute of Molecular Sciences (IMS), Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal.
Mitochondria metabolism is an emergent target for the development of novel anticancer agents. It is amply recognized that strategies that allow for modulation of mitochondrial function in specific cell populations need to be developed for the therapeutic potential of mitochondria-targeting agents to become a reality in the clinic. In this work, we report dipolar and quadrupolar quinolizinium and benzimidazolium cations that show mitochondria targeting ability and localized light-induced mitochondria damage in live animal cells.
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