Dual Emission of meso‐Phenyleneethynylene–BODIPY Oligomers: Synthesis, Photophysics, and Theoretical Optoelectronic Study

Abstract

Two series of 2,5‐di(butoxy)phenyleneethynylenes, one halogenated (nPEC4‐X; n=2, 3, or 4) and the other boron‐dipyrromethene (BODIPY) terminated (nPEC4‐By; n=3, 4, or 5; By=BODIPY), were synthesized monodirectionally by the step‐by‐step approach and the molecular structure was corroborated by NMR spectroscopy (1H, 13C‐DEPTQ‐135, COSY, HSQC, HMBC, 11B, 19F) and MALDI‐TOF mass spectrometry. The multiplicity and J‐coupling constants of 1H, 11B, and 19F/11B NMR signals revealed, in the nPEC4‐By series, that the phenyl in the meso position of BODIPY becomes electronically part of the conjugation of the phenyleneethynylene chain, whereas BODIPY is electronically isolated. The photophysical, electrochemical, and theoretical studies confirm this finding because the properties of nPEC4‐By are comparable to those of the nPEC4‐X oligomers and BODIPY, indicating negligible electron communication between BODIPY and the nPEC4 moieties. Nevertheless, energy transfer (ET) from nPEC4 to BODIPY was rationalized by spectroscopy and theoretical calculations. Its yield decreases with the nPEC4 conjugation length, according to the increase in distance between the two chromophores, resulting in dual emission for the longest oligomer in which ET is quenched.

Electron‐Donating and Electron‐Withdrawing Subunit Effects on Coumarin‐BODIPY Dyads: Optical and Electrochemical Properties and Molecular Interactions

“…Absorption, fluorescence, and 3D‐fluorescence measurements of all synthesized coumarins ( C1 ‐ C3 ) and coumarin‐BODIPYs ( B1 ‐ B3 ) were measured in dichloromethane and all data are given in Table 1. The main transition band, which represents the transition from S0 to S1 in the UV‐Vis spectrum of BODIPY compounds, is observed at 502 nm and it consistent with the literature [34] . The absorption wavelengths of B1 and B2 from the coumarin moieties are observed at 340 nm, while the absorption wavelength of B3 from the coumarin moiety is observed at 380 nm.…”

“…The main transition band, which represents the transition from S0 to S1 in the UV-Vis spectrum of BODIPY ChemPhotoChem compounds, is observed at 502 nm and it consistent with the literature. [34] The absorption wavelengths of B1 and B2 from the coumarin moieties are observed at 340 nm, while the absorption wavelength of B3 from the coumarin moiety is observed at 380 nm. This difference is due to the effect of the strong electron donor À NMe 2 group on the coumarin ring.…”

Synthesis of Polysubstituted Symmetrical BODIPYs via Fischer Carbene Complexes: Theoretical, Photophysical and Electrochemical Evaluation

“…iv) In contrast, phenols in 3,5‐position ( B ) give rise to irreversible redox process, likely because phenols stabilize the dianions and dications formed during the redox process (hydroquinones are used as radical inhibitors), this is interesting because when phenols are in meso ‐position ( C ) 6 d , the reversibility and the molecular orbitals or the E gap energies are maintained with respect to 6 b . A similar behavior is observed for a nitro‐phenyl in meso ‐position 6 e , thus supporting the statement that aryls in meso ‐position do not electronically participate in the BODIPYs core [53] . In both, 6 d and 6 e a broadening of redox waves is observed because such groups can be reduced and oxidized in a wide electrochemical window.…”

“…A similar behavior is observed for a nitrophenyl in meso-position 6 e, thus supporting the statement that aryls in meso-position do not electronically participate in the BODIPYs core. [53] In both, 6 d and 6 e a broadening of redox waves is observed because such groups can be reduced and oxidized in a wide electrochemical window. v) In view of a possible application of the series as molecular organic electrophores for the development of redox flow batteries (RFBs), [54] the energy distance (ΔE) between the two redox transitions was calculated, Table 5, Figures 9(a), S133 and S134.…”

A NIR-Fluorochrome for Live Cell Dual Emission and Lifetime Tracking from the First Plasma Membrane Interaction to Subcellular and Extracellular Locales

“…Yet a distinct limitation of off-to-on fluorophores is that data are only obtainable in the on-state as, by default, the fluorescent silent off-state yields no information. A more data-rich construct than off-to-on responsive would be the counterintuitive sounding design of on-to-on, in which a fluorophore can exist in two interconvertible, response-differing, and discernable on-states [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. In this way, data can be collected simultaneously from both on-states, doubling the number of data sources.…”