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Updated: Dec 30, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Photoinduced Intramolecular Charge Transfer and Hyperpolarizability Coefficient in Push-Pull Pyridinium Salts with
Alessio Cesaretti1, Carmela Bonaccorso2, Fausto Elisei1
1Department of Chemistry Biology and Biotechnology, and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), University of Perugia, via Elce di Sotto 8, 06123, Perugia, Italy.
Abstract:
The synthesis of three push-pull cationic dyes is reported here together with a photophysical study carried out by stationary and ultrafast spectroscopies. The hyperpolarizability (β) values of the three molecules have been estimated through a simple solvatochromic method based on conventional, low-cost equipment, which had been tested previously with success in our laboratory. The investigated pyridinium salts showing strong negative solvatochromism bear the same piperidine ring as a strong electron-donor group and the same thiophenes as electron-rich π-linkers, but differ in terms of the N-substituent on the electron-acceptor pyridinium unit, namely N-methyl in compound A, N-pyrimidin-2yl in B and N-2,4-dinitrophenyl in C. The derived β values were found to increase (in the order A
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