Triptycenes have general applicability for increasing the alignment of fluorescent and dichroic dyes in LC hosts. Dyes containing varying numbers of triptycenes were synthesized to study the effect of free-volume alignment of triptycenes on the alignment of dyes. These dyes were designed such that multiple triptycenes could be incorporated and the triptycene-free volume is coincident to the aspect ratio of the dye, allowing a cooperative effect to increase their overall average alignment. With increasing triptycene incorporation, a stepwise increase in the alignment parameters of each dye was seen. It was also found that the attachment of one triptycene group has a negligible effect on the optical switching response times of the dyes. This can be a powerful tool for designing dyes with higher alignments for a variety of applications including guest-host reflective LCDs and holographic data storage.
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http://dx.doi.org/10.1021/ja017499x | DOI Listing |
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November 2024
Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, 462066, India.
Chem Sci
July 2024
Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8501 Japan
Controlling the rotation of carbon-carbon bonds, which is ubiquitous in organic molecules, to create functionality has been a subject of interest for a long time. In this context, it would be interesting to explore whether cooperative and collective rotation could occur if dipolar molecular rotors were aligned close together while leaving adequate space for rotation. However, it is difficult to realize such structures as bulk molecular assemblies, since molecules generally tend to assemble into the closest packing structure to maximize intermolecular forces.
View Article and Find Full Text PDFJ Phys Chem A
March 2024
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China.
Thermally activated delayed fluorescence (TADF) emitters based on the triptycene skeleton demonstrate exceptional performance, superior stability, and low efficiency roll-off. Understanding the interplay between the luminescent properties of triptycene-TADF molecules and their assembly environments, along with their excited-state characteristics, necessitates a comprehensive theoretical exploration. Herein, we predict the photophysical properties of triptycene-TADF molecules in a thin film environment using the quantum mechanics/molecular mechanics method and quantify their substantial dependency on the heavy atom effects and reorganization energies using the Marcus-Levich theory.
View Article and Find Full Text PDFDalton Trans
August 2023
College of Chemistry, Green Catalysis Center, International Phosphorus Laboratory, International Joint Research Laboratory for Functional Organophosphorus Materials of Henan Province, Zhengzhou University, Zhengzhou 450001, P. R. China.
A new class of phosphorus-doped triptycenes was designed and synthesized a Diels-Alder reaction between alkynylphosphonates and anthracene, followed by oxidative cyclization. The packing interaction and molecular alignment in the single crystals revealed that the weak C-H⋯π (2.825 Å) interaction guides the self-assembly of phosphindole oxide iptycenes.
View Article and Find Full Text PDFChem Sci
June 2022
Institute of Theoretical and Computational Chemistry, Heinrich-Heine-University Düsseldorf D-40204 Düsseldorf Germany
Quantum chemical studies employing combined density functional and multireference configuration interaction methods suggest five excited electronic states to be involved in the prompt and delayed fluorescence emission of TpAT-tFFO. Three of them, a pair of singlet and triplet charge transfer (CT) states (S and T) and a locally excited (LE) triplet state (T), can be associated with the (Me → N) conformer, the other two CT-type states (S and T) form the lowest excited singlet and triplet states of the (Me → Ph) conformer. The two conformers, which differ in essence by the shearing angle of the face-to-face aligned donor and acceptor moieties, are easily interconverted in the electronic ground state whereas the reorganization energy is substantial in the excited singlet state, thus explaining the two experimentally observed time constants of prompt fluorescence emission.
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