Porphyrin cyclophane , consisting of two rigidly fixed but still movable cofacial porphyrins and exposing acetate-masked thiols in opposed directions of the macrocycle, is designed, synthesized, and characterized. The functional cyclophane , as pioneer of mechanosensitive 3D materials, forms stable single-molecule junctions in a mechanically controlled break-junction setup. Its reliable integration in a single-molecule junction is a fundamental prerequisite to explore the potential of these structures as mechanically triggered functional units and devices.
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http://dx.doi.org/10.1021/acs.joc.0c01957 | DOI Listing |
Angew Chem Int Ed Engl
October 2024
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore.
J Phys Chem Lett
April 2024
Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States.
Solvent reorganization energies, free energies, and entropies are obtained for photoexcitation of three molecules that exhibit strong solvatochromism [Nile red, 5-(dimethylamino)-5'-nitro-2,2-bisthiophene, and Reichardt's dye B30] by measuring their optical absorption spectra at temperatures between 150 and 300 K in solvents with a range of polarities. Energies, free energies, and entropies of solvent reorganization are also obtained from computer simulations of three intramolecular electron-transfer reactions (charge separation and recombination in Zn-porphyrin-quinone cyclophane and charge transfer in a bis-biphenylandrostane radical anion). Entropy-enthalpy compensation in the solvent reorganization free energy for photoexcitation or electron transfer is found to be essentially complete (having nearly equal and opposite contributions from entropic and enthalpic effects) for all of the processes with solvent reorganization energies less than about 0.
View Article and Find Full Text PDFJ Am Chem Soc
April 2023
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
Near-infrared (NIR) light is known to have outstanding optical penetration in biological tissues and to be non-invasive to cells compared with visible light. These characteristics make NIR-specific light optimal for numerous biological applications, such as the sensing of biomolecules or in theranostics. Over the years, significant progress has been achieved in the synthesis of fluorescent cyclophanes for sensing, bioimaging, and making optoelectronic materials.
View Article and Find Full Text PDFRSC Med Chem
March 2023
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University 2205 Songhu Road Shanghai 200438 China
Chem Sci
July 2022
Kavli Institute of Nanoscience, Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands
Intra- and intermolecular interactions are dominating chemical processes, and their concerted interplay enables complex nonequilibrium states like life. While the responsible basic forces are typically investigated spectroscopically, a conductance measurement to probe and control these interactions in a single molecule far out of equilibrium is reported here. Specifically, by separating macroscopic metal electrodes, two π-conjugated, bridge-connected porphyrin decks are peeled off on one side, but compressed on the other side due to the covalent mechanical fixation.
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