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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 14: Poster
KFM 14.22: Poster
Mittwoch, 19. März 2025, 17:00–18:30, P1
Investigation of Pressure-Induced Dimerization in a Pyrene-based Dyad Crystal: Associated with Auxiliary exhibition of thermally Induced Intramolecular Charge Transfer — •Argha Barman1, Agniezska Huć2, and Krishnayan Basuroy1 — 1DESY, Hamburg, Germany — 2University of Warsaw, Poland
We present the design and photophysical properties of a D-B-A dyad with N, N-dimethylaniline (DMA) as the electron donor and pyrene (Py) as the acceptor, linked by a -CH=CH- chain. The molecule crystallizes in the triclinic space group P-1, undergoing a reversible phase transition with solvent-dependent transition temperatures (e.g., 200K in cyclohexane, 198K in toluene, 209K in dichloromethane). Structural changes include variations in bond lengths and pyramidalization at the tertiary nitrogen atom, with persistent strong π***π stacking. Photophysical analysis reveals a small HOMO-LUMO gap (3.06 eV) and temperature-dependent dual fluorescence from locally excited (LE) and intramolecular charge transfer/excimer (ICT) states, with ICT emission diminishing above 220K. Under hydrostatic pressure (0.5*2.0 GPa), the crystals exhibit piezochromic behavior with emission redshift and quenching. These multifunctional properties make Py-CH=CH-DMA crystals promising for optoelectronics and pressure sensors.
Keywords: piezochromic; ICT; excimer; optoelectronics; diamond anvil cell