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Design of Two‐Photon‐Excited Fluorescent Dyes Containing Fluoroborylene Groups
Author(s) -
Zaleśny Robert,
Szczotka Nina,
Grabarz Anna,
Ośmiałowski Borys,
Jacquemin Denis
Publication year - 2019
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.201900084
Subject(s) - substituent , fluorescence , conjugated system , excited state , chemistry , singlet state , molecule , two photon excitation microscopy , two photon absorption , absorption (acoustics) , phenylene , photochemistry , computational chemistry , materials science , stereochemistry , atomic physics , polymer , organic chemistry , physics , quantum mechanics , composite material , laser
Aiming at establishing structure‐property relationships for two‐photon absorption, we present the results of an in silico investigation of dyes containing fluoroborylene (BF) groups. More specifically, we analyze the electronic properties corresponding to the one‐ and two‐photon excitation to two lowest‐lying singlet states ( S 1 and S 2 ) using TD‐DFT and CC2 methods. BF‐ and BF 2 ‐containing fluorescent dyes are in the limelight, but it remains challenging to reach the larger electronic two‐photon transition strengths needed in bioimaging applications. Hence, we put an emphasis on maximizing those strengths through structural variations. To this end, we consider 138 unique molecules deriving from five different structural cores presenting BF/BF 2 groups. This molecular set encompasses representatives of three architectures, built with different arrangements of electron‐donating (D) and electron‐withdrawing (A) moieties: D‐A, D‐A‐D and D‐A‐A‐D. In addition, we consider several π‐conjugated linkers of different lengths, composed of ethylene (en) and 1,4‐phenylene (PH) units (up to ‐enPHenPH‐), and a panel of substituents (R=H, OMe, NMe 2 and NPh 2 ). For the two‐photon transitions, it is shown that not only the linker extension and the strength of the electron‐donating substituent are crucial for maximizing the two‐photon activity but also the central core possessing fluoroborylene unit. The results have been rationalized by using a generalized three‐level model.