Two-photon absorption in imidazo[1,2-a]pyridine derivatives: Study of nonlinear optical response and dipolar properties

Imidazo[1,2-a]pyridine derivatives are versatile molecules with excellent emissive properties, making them interesting for various applications, from fluorescent probes to organic light-emitting diodes (OLEDs). Furthermore, such molecules enable the incorporation of different peripheral groups during the synthesis, which can improve the desired optical properties. However, there is a lack of studies that report this compounds class linear and nonlinear optical characteristics. Here, spectroscopic measure-ments were performed on seven imidazo[1,2-a]pyridine derivatives with different peripheral groups, to understand their influence on the two-photon absorption (2PA) cross-section. Results showed that the effective increase molecular conjugation, provided by the naphthalene substituent, leads to an increase of approximately seven times in the 2PA cross-section. Furthermore, it was shown that the same result is obtained when groups with a strong electron withdrawing or donating character are linked to the imidazo[1,2-a]pyridine core. Such results indicate a possible route to obtaining considerable nonlin-ear optical responses in this organic compounds class.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

In this study, spectroscopic measurements were conducted on seven imidazo[1,2-a]pyridine derivatives with different peripheral groups to investigate their influence on the two-photon absorption (2PA) cross-section. The results revealed that introducing a naphthalene substituent led to an approximately seven-fold increase in the 2PA cross-section, indicating the effective enhancement of molecular conjugation. Similarly, when groups with strong electron withdrawing or donating characteristics were linked to the imidazo[1,2-a]pyridine core, the same outcome was observed. These findings suggest a potential approach to achieving significant nonlinear optical responses in this class of organic compounds.