# Solvent Effects on the Photophysical Properties of Unexplored Imidazo[1,2‑a]pyridine Derivatives

## TL;DR

This paper explores how different solvents affect the light-emitting properties of newly synthesized imidazo[1,2-a]pyridine compounds.

## Contribution

The study reports the first investigation of photophysical properties of imidazo[1,2-a]pyridine derivatives and their solvent-dependent behavior.

## Key findings

- Bromo- and nitro-substituted derivatives showed a blue shift in absorption spectra.
- Cyano-substituted derivatives exhibited a red shift in absorption.
- Solvent polarity caused red or blue shifts in fluorescence spectra, indicating solvent effects on ICT mechanisms.

## Abstract

Simple imidazo­[1,2-a]­pyridine derivatives
were
synthesized via the GBB reaction, and their photophysical properties
were studied for the first time. Fluorescence quantum yields confirmed
a push–pull design, and absorption spectra showed a blue shift
for bromo- and nitro-substituted derivatives at the ortho position (4b, 4d), whereas the cyano-substituted
analogs at the para position (4f, 4p) exhibited a red shift. Solvent polarity significantly
affected the fluorescence spectra, causing a red shift in polar solvents
(4p, 4r) and a blue shift in nonpolar solvents
(4i, 4m). A significant Stokes shift supported
the involvement of an ICT mechanism in most cases. Some of the compounds
demonstrated promising properties for use in fluorescent materials.