In:
Physical Chemistry Chemical Physics, Royal Society of Chemistry (RSC), Vol. 23, No. 32 ( 2021), p. 17402-17407
Abstract:
The origin of the large difference of fluorescence yields between benzo[ a ] and benzo[ b ] BODIPY derivatives was investigated. The benzo[ a ]-BODIPY chromophore shows high fluorescen ce yields while the totally quenched fluorescence of benzo[ b ]-BODIPYs is observed. Quantum calculations indicated that larger spin–orbit coupling (SOC) and smaller singlet–triplet energy gaps result in non-fluorescence for benzo[ b ]-BODIPY. Benzo[ b ]-fusion makes a partial contribution to the HOMO but a full contribution to the HOMO−1, and thus the S 1 → S 0 and T 2 → S 0 transitions, involved in HOMO–LUMO and HOMO−1–LUMO, have different characteristics, which leads to spin flipping for intersystem crossing (ISC) and increases the SOC to 1.70 cm −1 . However, benzo[ a ] contributes to HOMO and HOMO−1 equally, and minimizes the SOC between S 1 and T 2 , leading to slow ISC from S 1 , thus possessing strong fluorescence. These results are useful for the rational design of heavy-atom-free triplet organic chromophores.
Type of Medium:
Online Resource
ISSN:
1463-9076
,
1463-9084
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2021
detail.hit.zdb_id:
1476283-3
detail.hit.zdb_id:
1476244-4
detail.hit.zdb_id:
1460656-2
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