Work

Investigating XC-functionals towards describing experimentally relevant excited-state properties of NIR-BODIPY derivatives

Year: 2025

Type: article

Abstract: The predictive and analytical power of time-dependent density functional theory (TD-DFT) has been instrumental in the design and mechanistic understanding of numerous organic chromophores. Yet, the widely popular boron-dipyrromethene (BODIPY) dye class suffers from notorious TD-DFT accuracy issues, undermining the serviceability of the technique. Highly correlated wave function approaches are much better at reproducing photophysical properties but become computationally unviable when making the push towards larger near-infrared (NIR) active structures. In an effort to find the protocol most capable of helping experimentalists design and analyze novel NIR BODIPYs, we have benchmarked 11 global or range-separated hybrid exchange-correlation functionals (XCFs) with different amounts of Hartree-Fock exchange. By relating both transition energies and oscillator strengths, first through a set of resolution-of-the-identity second-order coupled cluster (riCC2) calculations and then directly to experimental data, it is revealed that M06-2X and M06-HF behave most consistently for singlet and triplet excitations. To optimize accuracy across states, we recommend a hybrid approach where singlets are obtained through full TD-DFT and triplets are treated using the Tamm-Dancoff approximation.

Source: Physical Chemistry Chemical Physics

DOI: 10.1039/d5cp01830g

Authors: Mathias Fraiponts, Wouter Maes, Benoît Champagne

Institutions: University of Namur, IMEC, Namur Institute of Structured Matter, Hasselt University

Language: English

Topic: Advanced Chemical Physics Studies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green