A Small Push–Pull Fluorophore for Turn-on Fluorescence

Abstract

A new class of push-pull dyes is reported based on the structures of benzoxa- and benzothiadiazole heterocycles. This new class of dyes displays red-shifted wavelengths of emission and greater sensitivity to polarity and hydrogen bonding solvents relative to previously known derivatives.

Highly selective staining and quantification of intracellular lipid droplets with a compact push–pull fluorophore based on benzothiadiazole

“…CBD-Fluor, however, displayed a stronger bias in this turn-on behavior relative to other LD-specific dyes (Fig. 3B), 13,14,23,26 with a limit of detection in dioxane that was less than 200 pM (Fig. S1 †).…”

“…Thus, we hypothesized that CBD-Fluor would be ideal for applications in lipid staining to address current shortcomings in standard LD analysis with Nile Red. 26 versus Nile Red 27 demonstrated by an unchanged absorption spectrum for CBD-Fluor versus photodecomposition of Nile Red. Solutions of each dye were prepared in air saturated THF with identical optical density (0.12 absorbance units) at 455 nm and were continuously irradiated using an LED source with an irradiance of 370 mW cm −2 .…”

“…In the context of benzothiadiazoles, push-pull substitution patterns (such as the one exhibited by CBD-Fluor) can red-shift spectral features while maintaining a small size. 26,[28][29][30][31] Spectral characteristics of CBD-Fluor are ideal for LD imaging The compact and polar structure of CBD-Fluor compared to other polycyclic aromatic dyes has the potential to improve solubility in water in order to diminish non-specific staining and disruption of native interactions. Despite this compact structure, however, CBD-Fluor emits similarly to larger cellimaging dyes such as Nile Red, BODIPY, and fluorescein (>400 nm, Fig.…”

“…Herein, we report the use of a compact and more polar fluorophore, CBD-Fluor ( Fig. 1), 26 that leads to more red-shifted wavelengths of emission, higher photostability, higher turn-on fluorescence response, and excellent contrast with background for the selective staining of lipid droplets.…”

Identification of the Irreversible Redox Behavior of Highly Fluorescent Benzothiadiazoles

“…Subsequent coupling reactions like Sonogashira, Suzuki, and Buchwald-Hartwig coupling give access to a plethora of symmetrical and unsymmetrical derivatives. [1][2][3][4] BTDs can be applied in organic light-emitting diode (OLED) materials, [5][6][7] polymers with defined electronic and optical properties, [8][9][10] in sensory metal-organic frameworks, [11] solar cells [12] or in field-effect transistors (FET). [13] Furthermore, BTDs can act as ortho-diamine protecting groups and can thus be used as precursors for other molecular compounds, e. g. diaminodicyanoquinones and quinoxalines.…”