Photophysical properties of a boron analogue of coumarin†
Huayi Wang,Briana R. Schrage,Kana Takematsu,Christopher J. Ziegler
Physical Chemistry Chemical Physics Pub Date : 08/12/2021 00:00:00 , DOI:10.1039/D1CP02386A
Abstract

In this report, we present a study into the structure and electronic properties of difluoroboronsalicylaldoxime (DFBS), a boron-based structural analog of coumarin. The modification of the heterocyclic ring of coumarin with boron results in a compound with similar structural parameters and molecular orbitals to coumarin. DFT and TDDFT calculations reveal a significant stabilization of the LUMO in DFBS; this is supported by a ∼40 nm red shift of the lowest electronic transition in the absorption spectrum. Interestingly, DFBS is emissive, while unmodified coumarin is effectively non-radiative. Comparisons between DFBS, emissive coumarin variants, and unmodified coumarin suggest that the charge transfer character of the transition contributes to the fluorescence.

Graphical abstract: Photophysical properties of a boron analogue of coumarin