A new analysis of the optical properties of the molecular rotor 1,4-diphenyl-1,3-butadiyne (diphenyl-diacetylene, DPDA) is presented, taking account of the conformational dynamics. The absorption spectra are interpreted in terms of simultaneous contributions from planar as well as non-planar rotamers, characterized by a temperature dependent equilibrium distribution. The investigation is based on IR Linear Dichroism and UV Synchrotron Radiation Linear Dichroism (SRLD) spectroscopy on oriented samples in stretched polyethylene (PE), and on variable temperature UV spectroscopy. The study is supported by the results of detailed quantum chemical Time Dependent Density Functional Theory (TD-DFT) calculations. The resulting analysis has profound implications for the understanding of the optical, photochemical, and photophysical characteristics of this and related chromophores, of importance in a variety of applications.
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http://dx.doi.org/10.1039/c0cp02914a | DOI Listing |
Molecules
January 2025
Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Effectively regulating the rotary motions of molecular rotors through external stimuli poses a tremendous challenge. Herein, a new type of molecular rotor based on azobenzene-strapped mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complex is reported. Electronic absorption and H NMR spectra manifested the reversible isomerization of the rotor between the configuration and the configuration.
View Article and Find Full Text PDFBioconjug Chem
January 2025
Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1,Canada.
The ability to label synthetic oligonucleotides with fluorescent probes has greatly expanded their nanotechnological applications. To continue this expansion, it is essential to develop approachable, modular, and tunable fluorescent platforms. In this study, we present the synthesis and incorporation of an amino-formyl-thieno[3,2-]thiophene (AFTh) handle at the 5'-position of DNA oligonucleotides.
View Article and Find Full Text PDFSoft Matter
January 2025
INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, Université de Strasbourg, F-67000 Strasbourg, France.
Characterization of nanoscale formulations is a continuous challenge. Size, morphology and surface properties are the most common characterizations. However, physicochemical properties inside the nanoparticles, like viscosity, cannot be directly measured.
View Article and Find Full Text PDFMolecular rotor-based fluorophores (RBFs) that are target-selective and sensitive to both polarity and viscosity are valuable for diverse biological applications. Here, we have designed next-generation RBFs based on the underexplored bimane fluorophore through either changing in aryl substitution or varying π-linkages between the rotatable electron donors and acceptors to produce red-shifted fluorescence emissions with large Stokes shifts. RBFs exhibit a twisted intramolecular charge transfer mechanism that enables control of polarity and viscosity sensitivity, as well as target selectivity.
View Article and Find Full Text PDFNature
January 2025
Department of Chemistry, University of Manchester, Manchester, UK.
Cells display a range of mechanical activities generated by motor proteins powered through catalysis. This raises the fundamental question of how the acceleration of a chemical reaction can enable the energy released from that reaction to be transduced (and, consequently, work to be done) by a molecular catalyst. Here we demonstrate the molecular-level transduction of chemical energy to mechanical force in the form of the powered contraction and powered re-expansion of a cross-linked polymer gel driven by the directional rotation of artificial catalysis-driven molecular motors.
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