Dicyanostilbene-based two-photon thermo-solvatochromic fluorescence probes with large two-photon absorption cross sections: Detection of solvent polarities, viscosities, and temperature

Solvent tuned single molecule dual emission in protic solvents: effect of polarity and H-bonding

“…Stabilisation of the ground state results in a blue shift as compared to emission observed in strong polar aprotic solvents. 14,17 In our case, the same behaviour is obtained, and the ICT band maxima in protic solvent is blue shifted comparing acetonitrile (17 762 cm -1 ) and DMSO (17 271 cm -1 ) to 1butanol (19 305 cm -1 ) and methanol (18 149 cm -1 ), see Table S2 and S3 in the ESI.…”

“…In the present study, we assess the effect of protic solvents on the dual emission of Phen-PENMe 2 ( Figure 1). Such studies have been made on ICT molecules displaying pyrene, 13 stilbene, 14 9aminoacridine, 15,16 and imidazole 17 motifs as well as the 5-(4dimethylamino-phenyl)-penta-2,4-dienoic acid ethyl ester DMAPPDE compound. 18 In some of these cases, the contribution of a tautomerization (with an equilibrium being struck between ketoamine and enol-imine species) and an intramolecular H-bond render the problem more complex.…”

Indole-based Cyanine as a Nuclear RNA-Selective Two-Photon Fluorescent Probe for Live Cell Imaging

“…Upon excitation at their absorption maxima, these cyanines exhibit relatively strong fluorescence in the range of 536-546 nm in DMSO but very weak emission and low fluorescence quantum yield in aqueous medium which is attributed to the very rapid non-radiative decay caused by the strong and dynamic adhesive interactions with water molecules. 24 Nevertheless, upon binding to nucleic acid such as calf thymus DNA (ct-DNA) or 16S and 23S ribosomal RNA (rRNA), these cyanines would exhibit a significant spectral shift and strong fluorescence enhancement, particularly for the binding of MPI with rRNA showing more than 26-fold fluorescence enhancement (Supplementary Figure S3a) and 32-fold increase in fluorescence quantum yield (Table 1). This property is especially beneficial to the application of imaging of RNA distribution in a cellular environment.…”

A Dicyanocarbazolylstilbene‐Derived Two‐Photon Fluorescence Probe for Lipid Raft with a Large Two‐Photon Action Cross Section

“…We recently reported two solvatochromic probes (D-π-A, C=C) derived from TP fluorophore DCS (4-methyl-2,5-dicyano-4'-amino stilbene). Our probe exhibits a wide range of solvatochromism and a large δΦ, [19] therefore, becoming the preferred candidate for lipid raft imaging. Based on the molecular simulation calculation, Ai-Min Ren had theoretically proved that, as a fluorophore, DCS was able to lead to a significant increase in δΦ.…”

“…[20] On this basis, we modified the molecular structure of the probe by introducing a lipophilic long carbon chain (C 8 H 17 ), which is similar to that of eight carbon atoms in cholesterol with the purpose of augmenting the compatibility of the probe with the cytoplasmic membrane (biliphytic molecular layer), and improving the matching between probe molecule and lipid raft. In addition, the benzene ring was replaced by the fused-ring carbazole moiety to enhance the rigidity of molecular plane: one was to improve the two-photon absorption cross-section (δ TPA ) of the probe molecule to emit stronger fluorescence, which greatly heighten the sensitivity; the other was to reduce the effect of water solution polarity (or cell fluid polarity) upon the fluorescence of the probe, [19,21] and to focus the probe on the response to viscosity, namely lipid raft, so as to enhance the accuracy of the detection; another was to boost the affinity and efficacy of the probe with lipid raft rooting from the comparability between the rigidity of molecular plane for the probe and the rigid lipid raft with rich glycosphingolipids and cholesterol. The matching and similarity in the structure of probe molecule and cholesterol which both have four carbon rings (one five-membered ring and three six-membered rings) contributed to their highly specific recognition.…”