A BODIPY-Based Fluorescent Probe for Detection of Subnanomolar Phosgene with Rapid Response and High Selectivity

Abstract

A new type of phosgene probe with a limit of detection down to 0.12 nM, response time of less than 1.5 s, and high selectivity over other similarly reactive toxic chemicals was developed using ethylenediamine as the recognition moiety and 8-substituted BODIPY unit as the fluorescence signaling component. The probe undergoes sequential phosgene-mediated nucleophilic substitution reaction and intramolecular cyclization reaction with high rate, yielding a product with the intramolecular charge transfer (ICT) process from amine to the BODIPY core significantly inhibited. Owing to the emission feature of 8-substituted BODIPY that is highly sensitive to the substituent's electronic nature, such inhibition on the ICT process strikingly generates strong fluorescence contrast by a factor of more than 23 300, and therefore creates the superhigh sensitivity of the probe for phosgene. Owing to the high reactivity of ethylenediamine of the probe in nucleophilic substitution reactions, the probe displays a very fast response rate to phosgene.

A BODIPY‐Based Fluorescent Probe to Visually Detect Phosgene: Toward the Development of a Handheld Phosgene Detector

“…Recent progress on the critical subject of detection has enriched current knowledge for designing molecular probes, especially for phosgene . In general, detecting phosgene with a molecular probe involves trapping the molecule using a reactive site (e.g., hydroxy and amine functional groups), which, following structural modification, generates a detectable optical signal, for example a colour change or fluorescence emission.…”

“…Scheme depicts general detection strategies, which involve trapping phosgene through a chemical reaction. Among widely used recognition units, o ‐phenylenediamine (OPA) is unique given its exceptional specificity for phosgene (Scheme c). In most cases, the OPA unit appended on the fluorophore core can efficiently quench fluorophore emission during a photo‐induced electron transfer (PET) process.…”

Blue-Emitting BODIPY Dyes

“…To date, various kinds of fluorescent probes for phosgene have been introduced [36]. In 2017, Tian and co-workers reported a phosgene probe based on 8-amino-BODIPY (8-EDAB, Figure 6) [37]. Phosgene reacts with primary amine moiety in 8-EDAB, which undergoes a fast intramolecular cyclization reaction (phosgene-mediated acidylation) to afford a urea-containing 8-amino-BODIPY.…”

Rhodamine‐based Colorimetric and Fluorescent Chemosensors for the Detection of Cu2+ Ions and its Application to Bioimaging

“…Unfortunately, these methods involve high-priced equipment and include inefficient and arduous procedures that can only be performed by experienced experts. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] Rhodamine 6G and B constitute another very significant class of metal sensors. As such, there has been a significant amount of resources devoted to design and development of novel fluorescence chemosensors to detect presence of metal ions.…”