A visible-near-infrared fluorescent probe for peroxynitrite with large pseudo-Stokes and emission shift via through-bond energy and charge transfers controlled by energy matching

Abstract

We reported a visible-near-infrared fluorescent probe for peroxynitrite detection with large pseudo-Stokes and emission shifts, based on through-bond energy transfer (TBET) in combination with intramolecular charge transfer (ICT).

New rhodamines with changeable π-conjugation for lengthening fluorescence wavelengths and imaging peroxynitrite

“…17 These observations are in accordance with the fact that the dibenzo [1,4]oxazepine core has some p-conjugation, whereas the spirolactam breaks the conjugation of the xanthene. On the other hand, both 1 H and 13 C NMR spectra of ON-RB showed symmetry breaking compared with those of rhodamine B hydroxylamide. 17 In the 1 H NMR spectrum (Figure S18), a proton with a weak but broad peak appeared at a rather low filed (12.65 ppm), suggesting that this greatly deshielded proton in the electron-deficient environment was possibly on the dibenzo [1,4]oxazepine core (Figure 1B).…”

“…Notably and unexpectedly, peroxynitrite (ONOO À ), an important reactive oxygen species (ROS), can selectively trigger the reconstruction of the p-conjugation of the derivatives, producing oxazine fluorophores with largely lengthened analytical wavelengths (Table S1). Although there have been a number of fluorescent probes for ONOO À assay, 12,13 our derivatives undergo a novel and more specific reaction with ONOO À (Figure 2A; Scheme S3; Figures S5D and S5H). For instance, reaction of ONOO À with ON-RB derived from rhodamine B can generate the corresponding oxazine fluorophore (oxazine 1) via the p-conjugation extension, which fluoresces even at 672 nm, approaching the near-infrared region (such a fluorophore of oxzaine 1 has been elegantly combined with nanomaterials to detect OCl À and ONOO À14 ).…”

Boronate-Based Probes for Biological Oxidants: A Novel Class of Molecular Tools for Redox Biology

“…In this review, we would be remiss to omit some examples of formylphenylboronic ester/acid usage in carbon-carbon bond formation. In those reactions, which are performed mostly in boiling anhydrous ethanol (Wang et al, 2013 ; Guo et al, 2018 ), the oxygen atom of the aldehyde group serves as a base (in some cases, DIPEA (Shu et al, 2020a , b ) or piperidine (Wu L. et al, 2019 ) is added), which abstracts an acidic proton from the reaction partner and the negatively charged carbon atom obtained attacks the protonated carbonyl group with subsequent double bond formation. For example, a single bond formation serves the reductive amination reaction in which a 2-(2-aminophenyl)benzothiazole reacts with the 4-formylphenylboronic pinacol ester in the presence of NaBH(OAc) 3 (Sedgwick et al, 2016 ).…”

A General Strategy for Through‐Bond Energy Transfer Fluorescence Probes Combining Intramolecular Charge Transfer: A Silyl Ether System for Endogenous Peroxynitrite Sensing

“…Ac ombination of TBET and ICT processes occurred upon chemicalt ransformation from phenylboronate to phenol, resulting from the strong oxidation of peroxynitrite. [27] The experimental results demonstrate that À OPh-PyO À is a good TBET system with large PSS and emission shift. In this work, a silyloxyphenylg roup was connected with ah ydroxypyrene or silyloxypyrene structure throughah ighly conjugated 1,2dimethylenehydrazine linker to give two donor-p-bridge-acceptor probes (SiOPh-PyOH and SiOPh-PyOSi)( Scheme 1).…”