Fluorescent detection of nerve agent simulants

Abstract

Chapter 2.2 Detection of nerve agent-related molecules based on BODIPY-salicylaldehyde oxime con-jugation was studied. Fluorescence intensity of the B-Sal-oxime species increases in the presence of diethyl cy-anophosphonate (DECP) whereas it decreases with of diethyl chlorophosphate (DCP) and diethyl methylphosphonate (DEMP). Benzonitrile formation in novel fluorescent B-sal-oxime system was elucidated using model substrates. Chapter 2.3 A new 1,8-naphthalimide fluorescent probe for the detection of diethyl cyanophosphonate, a very common nerve agent simulant, was synthesized and characterized fully. The probe showed ~50-fold en-hancement of fluorescence intensity over diethyl methylphosphonate. Importantly, the probe operates under aqueous conditions and neutral pH. The substitution reaction with the oxime group is fast

the resulting time-response of fluorescent enhancement was observed within ~30 s. It is also confirmed that the probe is able to detect diethyl cyanophosphonate in both gas and liquid phases through dual emissions available by silica plate assays. Chapter 3.1 A new fluorescent probe based on coumarin system for the detection of nerve agent simu-lants was developed. The probe showed the fluorescence enhancement with diethyl chlorophosphate over di-ethyl cyanophosphonate and diethyl methylphosphonate. This probe showed the fluorescence changes by in-tramolecular cyclization reaction. Chapter 3.2 Fluorescein as a reversible fluorescent sensor for nerve agent simulants diethyl chlorophos-phate (DCP), diethyl methylphosphonate (DEMP), and diethyl cyanophosphonate (DECP) was studied. Super-oxide allows for a “off-on” mechanism to regenerate fluorescein. The order of decrease in fluorescence inten-sity for nerve agents stimulants is DCP > DEMP >> DECP. Chapter 3.3 Chromogenic and fluorescent detection for nerve agents and simulants was studied with a meso-pyridyl-BODIPY system that showed selective chromogenic and fluorescent changes for Soman (GD) selectively. DFT calculations aided in determining the nature of the fluorescence “turn-off” signal and $\lambda_{abs,max} red-shifting$. Chapter 4.1 Two phenyl selenyl-based BODIPY turn-on fluorescent probes for detection of hypo-chlorous acid (HOCl) were synthesized whose emission intensity modulated by photo-induced electron transfer (PET) process. The probe 2 is intrinsically shows no background signal, however, after reaction with HOCl, oxidation of selenium foreclose PET process, which evoke a significant increase in fluorescence intensity. The fluorescence intensity of the probe 1 and 2 with HOCl shows a ~18 and ~50-fold fluorescent enhancement compared with that signal generated for other ROS.