Improving the quantum yields of fluorophores by inhibiting twisted intramolecular charge transfer using electron-withdrawing group-functionalized piperidine auxochromes

Abstract

Using sulfone-functionalized piperdine as an auxochrome, the quantum yields of rhodamine and its red to NIR derivatives in aqueous solution have substantially been improved.

A Systematic Study of Coumarin–Tetrazine Light‐Up Probes for Bioorthogonal Fluorescence Imaging

“…The prevailing explanation of the quantum‐yield enhancement is based on the expectation that the azetidine or dimethylpiperazinium substituents suppress the formation of twisted intramolecular charge transfer (TICT) upon photoexcitation . The TICT form relaxes without emission of a photon, which leads to non‐radiative decay of the photoexcited state and lower Φ .…”

Cyclooctatetraene-conjugated cyanine mitochondrial probes minimize phototoxicity in fluorescence and nanoscopic imaging

“…In superresolution imaging where uorophore brightness is of pivotal importance and in primary-cell analysis where genetic manipulations are cumbersome (if not impossible), organic dyes are indispensable reagents. In recent years, innovation in bioimaging dyes has mainly focused on brightness, 27,40,41 uorogenicity, 42,43 photostability, 7,44,45 and photo-switching. 5 Despite similarities in their mechanism, the distinctions between phototoxicity and photobleaching are important in uorophore design.…”

Extremely bright, near-IR emitting spontaneously blinking fluorophores enable ratiometric multicolor nanoscopy in live cells

“…For example, an EWG-containing fluorophore reported by Lv et al possesses an exceptional quantum yield (0.66) but is blue-shifted by ~20 nm relative to HMSiR (ƛ abs /ƛ em = 631/654 nm). 41 We hypothesized that combining the effects of restricted aryl-N bond rotation with an EWG would simultaneously reduce p K cycl and increase quantum yield by inhibiting TICT. If these changes were introduced into the HMSiR THQ scaffold, even a moderate decrease in excitation and emission maxima would not jeopardize the emission shift needed to remain orthogonal to HMSiR.…”

“…Despite these blue-shifts, Cal664sb displays a comparable quantum yield to a previously reported and exceptionally bright Si-rhodamine fluorophore (compound 9 in reference 41), but with a >30 nm longer emission maximum. 41…”