TY - JOUR TI - Design of Two-Photon-Excited Fluorescent Dyes Containing Fluoroborylene Groups AU - Zaleśny, Robert AU - Szczotka, Nina AU - Grabarz, Anna AU - Ośmiałowski, Borys AU - Jacquemin, Denis T2 - ChemPhotoChem AB - Abstract 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 ( and ) using TD-DFT and CC2 methods. BF- and BF2-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/BF2 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, NMe2 and NPh2). 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. DA - 2019/09/01/ PY - 2019 DO - 10.1002/cptc.201900084 DP - chemistry-europe.onlinelibrary.wiley.com (Atypon) VL - 3 IS - 9 SP - 719 EP - 726 J2 - ChemPhotoChem SN - 2367-0932 UR - https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cptc.201900084 Y2 - 2020/06/30/16:36:12 KW - density functional theory KW - fluorescent dyes KW - fluoroborylene groups KW - two-photon absorption ER -