Semibullvalene and Diazasemibullvalene: Recent Advances in the Synthesis, Reaction Chemistry, and Synthetic Applications

Zhang, Shaoguang; Zhang, Wen‐Xiong; Xi, Zhenfeng

doi:10.1021/acs.accounts.5b00190

“…The group of Rivera-Fuentes, tried to overcome the problem of photobleaching, a phenomenon that is observed after prolonged excitation, by photo-regulation of fluxional fluorophores [267]. Fluxional molecules can undergo rapid degenerate rearrangements in the electronic ground state and exhibit stochastic switching behavior [268][269][270]. Classical photoactivatable dyes start from a dark isomer which transforms to the fluorescent state upon photoirradiation.…”

Section: Super-resolution Microscopymentioning

confidence: 99%

Recent Progress in Small Spirocyclic, Xanthene-Based Fluorescent Probes

Keller

¹

,

Kamiya

²

,

Urano

³

2020

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The use of fluorescent probes in a multitude of applications is still an expanding field. This review covers the recent progress made in small molecular, spirocyclic xanthene-based probes containing different heteroatoms (e.g., oxygen, silicon, carbon) in position 10′. After a short introduction, we will focus on applications like the interaction of probes with enzymes and targeted labeling of organelles and proteins, detection of small molecules, as well as their use in therapeutics or diagnostics and super-resolution microscopy. Furthermore, the last part will summarize recent advances in the synthesis and understanding of their structure–behavior relationship including novel computational approaches.

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“…Fluxional molecules, which undergo rapid degenerate rearrangements in the electronic ground state, exhibit stochastic switching behavior. Despite the great interest in this phenomenon in organic 7,8 , coordination 9 , main group 10 , organometallic 11,12 , and theoretical chemistry 13,14 , only a few applications of fluxional molecules are known 15,16 . We envision that the juxtaposition of photoswitching and fluxionality could bring about new functional molecules with practical applications.…”

Section: Introductionmentioning

confidence: 99%

Photoregulated fluxional fluorophores for live-cell super-resolution microscopy with no apparent photobleaching

Halabi

¹

,

Pinotsi

²

,

Rivera‐Fuentes

³

2019

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Photoswitchable molecules have multiple applications in the physical and life sciences because their properties can be modulated with light. Fluxional molecules, which undergo rapid degenerate rearrangements in the electronic ground state, also exhibit switching behavior. The stochastic nature of fluxional switching, however, has hampered its application in the development of functional molecules and materials. Here we combine photoswitching and fluxionality to develop a fluorophore that enables very long (>30 min) time-lapse single-molecule localization microscopy in living cells with minimal phototoxicity and no apparent photobleaching. These long time-lapse experiments allow us to track intracellular organelles with unprecedented spatiotemporal resolution, revealing new information of the three-dimensional compartmentalization of synaptic vesicle trafficking in live human neurons.

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“…Fluxional molecules, which undergo rapid degenerate rearrangements in the electronic ground state, exhibit stochastic switching behavior. Despite the great interest in this phenomenon in organic 7,8 , coordination 9 , main group 10 , organometallic 11,12 , and theoretical chemistry 13,14 , only a few applications of fluxional molecules are known 15,16 . We envision that the juxtaposition of photoswitching and fluxionality could bring about new functional molecules with practical applications.…”

Section: Introductionmentioning

confidence: 99%

Photoregulated Fluxional Fluorophores for Live-Cell Super-Resolution Microscopy with No Apparent Photobleaching

Halabi¹,

Pinotsi²,

Rivera‐Fuentes

³

2019

Preprint

0

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Photoswitchable molecules have multiple applications in the physical and life sciences because their properties can be modulated with light. Fluxional molecules, which undergo rapid degenerate rearrangements in the electronic ground state, also exhibit switching behavior. The stochastic nature of fluxional switching, however, has hampered its application in the development of functional molecules and materials. Here we combine photoswitching and fluxionality to develop a fluorophore that enables very long (>30 min) time-lapse single-molecule localization microscopy in living cells with minimal phototoxicity and no apparent photobleaching. These long time-lapse experiments allow us to track intracellular organelles with unprecedented spatiotemporal resolution, revealing new information of the threedimensional compartmentalization of synaptic vesicle trafficking in live human neurons. ResultsDesign, synthesis, and mechanistic studies. To create photoregulated fluxional fluorophore PFF-1 ( Fig. 2a), we grafted an acylhydrazone photoswitchable unit 30,31 onto a rhodamine B scaffold. Probe PFF-1 was synthesized in two steps and high yields from rhodamine B (Fig. 2b). As a mechanistic control compound, we also synthesized probe 2, which could be obtained from intermediate 3 (Fig. 2b). We hypothesized that prior to photoactivation, PFF-1 should exist predominantly as the E isomer of the acylhydrazone and a dark, non-fluxional, spirocyclized derivative ( Fig. 2a). This structure was confirmed by X-ray crystallography ( Supplementary Fig. 1) and electronic absorption spectroscopy ( Supplementary Fig. 2). Upon photoisomerization with light of 410 nm, the fluorescence of a solution of PFF-1 in aqueous buffer (pH = 7) increases by 12-fold, whereas photoirradiation of compound 2 gives only a 1.6-fold increase under the same conditions (Fig. 2c). Furthermore, photoactivation of PFF-1 at pH = 5 led to an even larger increase in fluorescence of 22-fold, but for compound 2 the increase was only 3-fold. 1 H NMR and HPLC analysis of PFF-1 prior to photoactivation confirmed that, in solution, virtually all molecules are present as the E isomer ( Supplementary Fig. 3).Upon irradiation in a UV photoreactor (10 min, 375 nm) a photostationary state was reached with about 17% conversion of the E isomer into the Z form, as determined by both 1 H NMR and HPLC analysis ( Supplementary Fig. 3). Photoisomerization using an LED source (410 nm, 8.5 mW cm -1 ) proceeded with a quantum yield of 0.4(2)% at pH = 5 and 0.5(5)% at pH = 7.4 ( Supplementary Figs. 4-6), confirming that the photochemical process does not depend strongly on pH. After photoirradiation, the Z isomer did not revert to the E form thermally over a period of 2 h ( Supplementary Fig. 7). 10 ms). After this initial photoactivation step, cells were either imaged using only the fluxionality of PFF-1 (single photoactivation, Fig. 4a,c) or by repeating the photoactivation pulse every 10 min to replenish the population of fluxional molecules (sequential photoactivation, Fig. 4b,c...

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Semibullvalene and Diazasemibullvalene: Recent Advances in the Synthesis, Reaction Chemistry, and Synthetic Applications

Cited by 34 publications

References 74 publications

Recent Progress in Small Spirocyclic, Xanthene-Based Fluorescent Probes

Recent Progress in Small Spirocyclic, Xanthene-Based Fluorescent Probes

Photoregulated fluxional fluorophores for live-cell super-resolution microscopy with no apparent photobleaching

Photoregulated Fluxional Fluorophores for Live-Cell Super-Resolution Microscopy with No Apparent Photobleaching

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