Chemistry. 2021 Apr 20. doi: 10.1002/chem.202100922. Online ahead of print.
ABSTRACT
Heavy-atom-free sensitizers forming long-living triplet excited states via the spin-orbit charge transfer intersystem crossing (SOCT-ISC) process have potential to replace transition metal complexes in photonic applications. The efficiency of SOCT-ISC in BODIPY donor-acceptor dyads can be tuned by structural modification. Predicting the triplet state yields and reactive oxygen species generation quantum yields in a particular solvent is challenging due to a lack of quantitative structure-property relationship (QSPR) models. We analyzed data on 1 O 2 generation quantum yields (Φ Δ ) for >70 heavy-atom-free BODIPY in toluene, acetonitrile, and THF. To build reliable QSPR models, we synthesized new BODIPYs containing different electron donating groups, studied their optical and structural properties and the solvent dependence of 1 O2 , which confirmed the formation of triplet states via SOCT-ISC. More than 5000 quantum-chemical descriptors were calculated including descriptors using DFT, namely M06-2X functional. QSPR models predicting ΦΔ values were developed using multiple linear regression (MLR), which perform significantly better than other machine learning methods and show sufficient statistical parameters (R = 0.88 ̶ 0.91 and q 2 = 0.62 ̶ 0.69) for all three solvents. A small root mean squared error of 8.2% was obtained for ΦΔ values predicted using MLR model in toluene. QSPR and machine learning techniques can be useful for predicting ΦΔ values in different media and virtual screening of new heavy-atom-free BODIPYs with improved photosensitizing ability.
PMID:33876842 | DOI:10.1002/chem.202100922
