# Boron-Centered Compounds: Exploring the Optical Properties of Spiro Derivatives with Imidazo[1,5-a]Pyridines

**Authors:** Anita Cinco, G. Attilio Ardizzoia, Stefano Brenna, Bruno Therrien, Gioele Colombo

PMC · DOI: 10.3390/molecules30122552 · Molecules · 2025-06-11

## TL;DR

This paper explores the optical behavior of boron-based spiro compounds with imidazo ligands, showing different colors in solution and solid states.

## Contribution

The study introduces new boron-centered spiro compounds and reveals their unique fluorescence properties.

## Key findings

- The compounds emit blue light in solution, depending on ligand substituents.
- They show orange-red emission in the solid state.
- TD-DFT calculations explain the nature of the optical transitions.

## Abstract

Five boron-centered spiro compounds with imidazo[1,5-a]pyridin-3-yl phenols as ligands were synthesized and thoroughly characterized through 1H-NMR, 13C-NMR, infrared spectroscopy, and X-ray single crystal analysis. The fluorescence properties of these compounds in solution and in the solid state were investigated, revealing blue emission with wavelengths maxima dependent on the electronic properties of the substituents on the ligands in solution, and an orange-red emission in the solid state. Time-Dependent Density Functional Theory (TD-DFT) calculations were performed to describe the nature of the transitions

## Full-text entities

- **Chemicals:** Imidazo[1,5-a]Pyridines (MESH:C554655), 1H (-), 13C (MESH:C000615229), Boron (MESH:D001895), spiro compounds (MESH:D013141)

## Full text

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## Figures

10 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12195987/full.md

## References

69 references — full list in the complete paper: https://tomesphere.com/paper/PMC12195987/full.md

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Source: https://tomesphere.com/paper/PMC12195987