Optical and Spectroscopic Studies of 4- [(5-Amino-1-phenylindolizin-3-yl) carbonyl] benzonitrile and Its Conjugates with Silver Nanoparticles
Published 2026-06-11
Keywords
- 4-5APCB dye,
- Dipole moment,
- Silver nanoparticles (AgNPs),
- Fluorescence quenching,
- Photophysical properties
- DFT analysis,
- Solvent effects ...More
Copyright (c) 2026

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Abstract
The present study investigates the spectroscopic behaviour of 4-[(5-amino-1-phenylindolizin-3-yl) carbonyl] benzonitrile (4-5APCB) in various solvents of differing polarity. The absorption and fluorescence spectra were recorded to evaluate the solvent effect on the electronic transitions of the molecule. Ground- and excited-state dipole moments were estimated using solvatochromic correlation methods, while the theoretical ground-state dipole moment was calculated using the Gaussian 09 computational package. The dipole moment was found to increase from 0.473 D in the ground state to 14.8 D in the excited singlet state, indicating that 4-5APCB exhibits higher polarity in the excited state across all solvents studied. Furthermore, green-synthesized silver nanoparticles (AgNPs) were conjugated with 4-5APCB to explore their interactive and photophysical properties. Quenching of fluorescence intensity was observed in DMSO and ethanol solvents, showing the occurrence of a strong interaction between the dye and nanoparticles. This highlights that the conjugation of AgNPs with 4-5APCB enhances their potential as functional photonic and sensing materials, demonstrating their significance in nanomaterial-based optical applications.
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