Published : 2022-09-19

Spectroscopic probes. Influence of polymeric chain on photophysical properties of molecules exhibiting the presence of the tict state. Part II. The kinetics

Abstract

Fluorescence from the initially excited singlet state (LE) and the twisted intramolecular charge transfer (TICT) state of 4-(N,N-dimethylamino)benzoate (DMAB), 4-(N,iV-diethylammo)benzoate (DEAB), 4-(N-pyrrolidine)benzoate (PYR), 4-(N-piperidino)benzoate (PIP), 4-(N-morpholine)benzoate (MOR) and 4-(N-2,6-dimethylmorpholine)benzo-ate (26DMM) were compared with the free and polystyrene bound chromo-phores. Adaptation of Grabowski's TICT hypothesis allows to calculate the activation energy for TICT state formation, the back-reaction TICT <=>LE, and the thermally activated TICT fluorescence. The polymeric chain essentially does not change the activation energy (E1) for TICT state formation, indicating that the polymeric chain does not change the microscopic viscosity in the range affecting measurable changes in the TICT<=>LE equilibrium. Experimental results suggest that the polymer chain affects only the vibrational relaxation of the tested molecules without any significant effect on the thermodynamics of the TICT and LE states equilibrium. The fluorescence lifetime and fluorescence anisotropy measurements additionally support these conclusions.


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Bajorek, A., & Pączkowski, J. (2022). Spectroscopic probes. Influence of polymeric chain on photophysical properties of molecules exhibiting the presence of the tict state. Part II. The kinetics. Polimery, 46(1), 29–39. Retrieved from https://polimery.ichp.vot.pl/index.php/p/article/view/2046