Diethyl Chlorophosphate Research Articles

Highly emissive salicylidene Schiff bases (SASBs) in solution and their application in the detection of the chemical warfare agent mimic diethyl chlorophosphate

Salicylidene Schiff bases (SASBs) have attracted significant attention because they have unique properties and can be simply synthesized by the condensation reactions; however, their poor fluorescence in solution makes them unable to be used as a fluorescent turn-off probe and limits their application fields.

Metallic versus Semiconducting SWCNT Chemiresistors: A Case for Separated SWCNTs Wrapped by a Metallosupramolecular Polymer.

As-synthesized single-walled carbon nanotubes (SWCNTs) are a mixture of metallic and semiconducting tubes, and separation is essential to improve the performances of SWCNT-based electric devices. Our chemical sensor monitors the conductivity of an SWCNT network, wherein each tube is wrapped by an insulating metallosupramolecular polymer (MSP). Vapors of strong electrophiles such as diethyl chlorophosphate (DECP), a nerve agent simulant, can trigger the disassembly of MSPs, resulting in conductive SWCNT pathways. Herein, we report that separated SWCNTs have a large impact on the sensitivity and selectivity of chemical sensors. Semiconducting SWCNT (S-SWCNT) sensors are the most sensitive to DECP (up to 10000% increase in conductivity). By contrast, the responses of metallic SWCNT (M-SWCNT) sensors were smaller but less susceptible to interfering signals. For saturated water vapor, increasing and decreasing conductivities were observed for S- and M-SWCNT sensors, respectively. Mixtures of M- and S-SWCNTs revealed reduced responses to saturated water vapor as a result of canceling effects. Our results reveal that S- and M-SWCNTs compensate sensitivity and selectivity, and the combined use of separated SWCNTs, either in arrays or in single sensors, offers advantages in sensing systems.

Efficient one‐pot synthesis of 1‐chlorovinyl p‐tolyl sulfoxides from aldehydes and ketones by the Horner‐Wadsworth‐Emmons reaction

AbstractA variety of 2‐monosubstituted and 2,2‐disubstituted 1‐chlorovinyl p‐tolyl sulfoxides was synthesized through a one‐pot procedure by the Horner‐Wadsworth‐Emmons reaction of carbonyl compounds with [chloro(diethoxyphosphoryl)(p‐tolylsulfinyl)methyl]lithium, which was generated from diethyl chlorophosphate, chloromethyl p‐tolyl sulfoxide, and lithium diisopropylamide in advance. The in situ‐prepared sulfoxides were directly converted into alkynes via the sulfoxide/magnesium exchange reaction with i‐PrMgCl and the subsequent Fritsch‐Buttenberg‐Wiechell rearrangement of the resulting magnesium alkylidene carbenoids.

Sensitive fluorescence on-off probes for the fast detection of a chemical warfare agent mimic

Two highly sensitive probes bearing a nucleophilic imine moiety have been utilized for the selective detection of chemical warfare agent (CWA) mimics. Diethyl chlorophosphate (DCP) was used as mimic CWAs. Both iminocoumarin-benzothiazole-based probes not only demonstrated a remarkable fluorescence ON-OFF response and good recognition, but also exhibited fast response times (10s) along with color changes upon addition of DCP. Limits of detection for the two sensors 1 and 2 were calculated as 0.065μM and 0.21μM, respectively, which are much lower than most other reported probes. These two probes not only show high sensitivity and selectivity in solution, but can also be applied for the recognition of DCP in the gas state, with significant color changes easily observed by the naked eye.

Fluorescent Chemosensors with Varying Degrees of Intramolecular Charge Transfer for Detection of a Nerve Agent Mimic in Solutions and in Vapor.

Nerve agents are highly toxic organophosphorus compounds, and their possible use in terrorist attacks has led to increasing interest in the development of reliable and accurate methods to detect these lethal chemicals. In this paper, we have prepared six 6-aminoquinolines with various N-substituents as chemosensors for a nerve-agent mimic diethylchlorophosphate (DCP). The chemosensors with the nucleophilic pyridine-N atom as the active site detect DCP via a catalytic hydrolysis approach to form the protonated sensor. The nucleophilicity of the pyridine-N atom depends on the donating ability of the 6-amine group, which affects the intramolecular charge-transfer (ICT) character of sensors and the protonated sensors, leading to different fluorescence-response modes. The effects of the ICT character on the sensing property have been clarified. Among these charge transfer sensors, the sensor 3 displays ratiometric fluorescence response to DCP and a low limit of detection (8 nM). Furthermore, a facile testing strip with 3 has been fabricated with poly(ethylene oxide) for real-time selective monitoring of DCP vapor.

Unexpected Side Product Formed during LDA-induced Phosphonylation of Uridine

The LDA-induced coupling of 2′,3′,5′-O-protected uridine with diethyl chlorophosphate, during the synthesis of 6-phosphonouridine, is accompanied by the formation of an unexpected side product. LDA adds slowly to the C4 position of the 2′,3′,5′-O-protected uridine after the initial reaction with diethyl chlorophosphate. The presence of the phosphorochloridate facilitates the side reaction. This observation accounts for the previously reported low yield when conducting the coupling reaction for longer durations and suggests a new route for the synthesis of N-alkylated 6-phosphonocytidine analogues.

Chemical warfare simulant‐responsive polymer nanocomposites: Synthesis and evaluation

ABSTRACTNanomaterials that undergo a physical change upon chemical warfare agent (CWA) exposure can potentially be used in detectors to warn soldiers of their presence or in fabrics to provide on‐demand protection. In this study, hybrid nanoparticles (NPs) were prepared by grafting a CWA‐responsive polymer from a silicon dioxide (SiO2) surface using ring opening metathesis polymerization; the covalent functionalization of the polymers on the NP surface was confirmed by gel permeation chromatography, dynamic light scattering, and transmission electron microscopy analysis. The polymer‐grafted SiO2 NPs were found to undergo a pronounced decrease (approximately 200 nm) in their hydrodynamic radius upon exposure to CWA simulants trifluoroacetic acid and diethyl chlorophosphate in toluene. This decrease in hydrodynamic radius is attributed to the electrophile‐mediated ionization of the triarylmethanol responsive unit and represents a rare example of polycation formation leading to polymer chain collapse. We have ascribed this ionization‐induced collapse to the formation of a favorable stacking interaction between the planar triarylcations. These studies have important implications for the development of breathable fabrics that can provide on‐demand protection for soldiers in combat situations. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3034–3040

Determination of the chemical warfare agents Sarin, Soman and Tabun in natural waters employing fluorescent hybrid silica materials

A novel mesoporous silica material containing boron–dipyrromethene (BODIPY) moieties (I) is employed for the detection of nerve agent simulants (NASs) and the organophosphate nerve or chemical warfare agents (CWAs) Sarin (GB), Soman (GD), and Tabun (GA) in aqueous environments. The reactive BODIPY dye with an optimum positioned hydroxyl group undergoes acylation reactions with phosph(on)ate substrates, yielding a bicyclic ring. Due to aggregation of the dyes in water, the sensitivity of the free dye in solution is very low. Only after immobilization of the BODIPY moieties into the silica substrates is aggregation inhibited and a sensitive determination of the NASs diethyl cyanophosphonate (DCNP), diethyl chlorophosphate (DCP) and diisopropyl fluorophosphate (DFP) possible. The signaling mode is a strong quenching of the fluorescence, reaching LODs in the pM range. The best performing hybrid material was singled out from a library of hybrid silicas varying in morphology and surface functionalization. The response to actual CWAs such as GB, GD, and GA has also been tested, offering similar behavior as for the simulants. The proposed reaction mechanism has been verified by investigation of other model materials, containing for instance BODIPY moieties without an optimum hydroxyl group (III) or a BODIPY dye with an all-aliphatic counterpart (IV). The latter can only form a monocyclic reaction product, showing much less reactivity as I. Assays with other possible competitors have been additionally carried out, showing favorably low cross-reactivities. Finally, the determination of NASs in several natural waters has been demonstrated.

A chromogenic and ratiometric fluorogenic probe for rapid detection of a nerve agent simulant DCP based on a hybrid hydroxynaphthalene-hemicyanine dye.

A new cyanine dye (CYD) based on hybrid hydroxynaphthalene-hemicyanine has been synthesized and characterized. The chromogenic and ratiometric fluorogenic probe (CYD) enables a fast and highly sensitive response to an OP nerve agent mimic diethyl chlorophosphate (DCP) through tandem phosphorylation and intramolecular cyclization reaction within 1 min and with the detection limit as low as 18.86 nM. To our knowledge this is the first report of a hydroxyl assisted bathochromic shift in a selective chemodosimeter for DCP exhibiting a ratiometric response. TDDFT calculations were performed in order to demonstrate the electronic properties of the probe and the cyclized product. Moreover, the utility of the probe CYD for the detection of DCP in live cells, in the gas phase and in a spiked soil sample has also been demonstrated.

Nerve agent simulant diethyl chlorophosphate detection using a cyclization reaction approach with high stokes shift system

A intramolecular cyclization reaction-based “turn-on” fluorescent probe (CoumNMe2) for selective detection of diethyl chlorophosphate (DCP) over close competitors diethyl cyanophosphonate (DECP), and diethyl methylphosphonate (DEMP) was developed.

Potassium carbonate supported efficient synthesis of new diethyl arylphosphoramidates

A series of some new diethyl arylphosphoramidates have been synthesized from the reaction of diethyl chlorophosphate with different amines in the presence of 5mol% of potassium carbonate catalyst. This reaction is operationally simple and efficient to afford the products with high yields in short reaction times. All the compounds synthesized were characterized by spectroscopic and elemental analysis. Summarizing our catalyst and solvent optimization studies we are reporting that potassium carbonate and DMSO is a best catalyst system for the synthesis of phosphoramidates.

Discrimination of tabun mimic diethyl cyanophosphonate from sarin mimic diethyl chlorophosphate via Zn(ii)-triggered photoinduced electron transfer-decoupled excited state intramolecular proton transfer processes

PET-coupled ESIPT platform and its Zn2+ complex are used for the discrimination of the nerve agent mimics DCNP and DCP.

Hyperbranched polymer based fluorescent probes for ppt level nerve agent simulant vapor detection

A terpyridine end capped hyperbranched polymer for the sensitive detection of sarin mimic diethyl chlorophosphate.

Smart hydrogel sensor for detection of organophosphorus chemical warfare nerve agents

ABSTRACTA novel “turn-off” fluorescence, smart hydrogel sensor for detection of a nerve agent simulant has been developed and tested. The smart hydrogel chemosensor has demonstrated an extremely fast and select fluorescence quenching detection response to the Sarin simulant diethylchlorophosphate (DCP) in the aqueous and vapor phases. The fluorogenic sensor utilizes 6,7-dihydroxycoumarin embedded in an polyacrylamide hydrogel matrix as the fluorescent sensing material. The rapid fluorescence quenching of the smart hydrogel films could easily be observed with the naked eye using a hand-held UV light at λ = 365 nm which demonstrates their practical application in real-time on-site monitoring.

A dual responsive molecular probe for the efficient and selective detection of nerve agent mimics and copper (II) ions with controllable detection time

The bifunctional azoaniline-based colorimetric and fluorometric molecular probe [(E)-4-((2,4-diaminophenyl)diazenyl)phenol] (Azo) was synthesized in this study for the sensing of diethylchlorophosphate (DCP), a nerve agent mimic, whereby a tunable detection time was concurrently obtained. Azo exhibited an excellent sensitivity and selectivity toward DCP through a formation of the electron-deficient NH-PO(OEt)2 group in acetonitrile (Azo-N). The probe showed a 63nm red shift in its absorption maximum upon the addition of DCP that was accompanied by a change in the color of the solution from pale yellow to dark red. In addition to the detection of DCP, Azo also showed colorimetric and turn-on fluorometric responses, also with a high selectivity and sensitivity, toward Cu2+ ions via a Cu2+-ion-catalyzed cyclization reaction that forms a benzotriazole ring (Azo-Cu); moreover, the consecutive sensing was achieved through a sequential process, whereby the addition of the Cu2+ ions was followed by the addition of DCP (Azo-Cu-N). Interestingly, the detection time of the Azo-Cu toward DCP after the sensing of the Cu2+ ions is much slower than that of Azo, indicating that the detection time toward DCP could be controlled by the cyclization extent through a changing of the amount of Cu2+ ions that is added.

Aggregation State Reactivity Activation of Intramolecular Charge Transfer Type Fluorescent Probe and Application in Trace Vapor Detection of Sarin Mimics

The reactivity of most Intramolecular Charge Transfer (ICT) based probes in the film state is much poorer than that in solution, due to the serious solid state aggregation of the large polarity molecules. In this contribution, an efficient method for activating the aggregation state reactivity of ICT based probes has been developed. Multiple hydrogen bonds formed by the oxime group, together with the phenol anion, could activate the aggregation state reactivity of the oxime group. By enhancing frontier orbital energy level, and constructing porous film structure, the probe becomes more compatible for highly efficient vapor phase reaction. In application, the TOP-I film can distinguish different organic phosphates with significant fluorescence change. The detection limit for diethyl chloro phosphate (DCP) is 1.2 ppb, lower than the Immediately Dangerous to Life and Health (IDLH) level of Sarin. Such a reactivity activating strategy can be extended to detect other harmful vapors by inducing suitable functio...

A Fluorescent Sensor for Dual-Channel Discrimination between Phosgene and a Nerve-Gas Mimic.

The ability to analyze highly toxic chemical warfare agents (CWAs) and related chemicals in a rapid and precise manner is essential in order to alleviate serious threats to humankind and public security caused by unexpected terrorist attacks and industrial accidents. In this investigation, we designed a o-phenylenediamine-pyronin linked dye that is capable of both fluorogenic and colorimetric discrimination between phosgene and the prototypical nerve-agent mimic, diethyl chlorophosphate (DCP) in the solution or gas phase. Moreover, this dye has been used to construct a portable kit that can be employed for real-time monitoring of DCP and phosgene in the field, both in a discriminatory manner, and in a simple and safe way.

A Fluorescent Sensor for Dual‐Channel Discrimination between Phosgene and a Nerve‐Gas Mimic

AbstractThe ability to analyze highly toxic chemical warfare agents (CWAs) and related chemicals in a rapid and precise manner is essential in order to alleviate serious threats to humankind and public security caused by unexpected terrorist attacks and industrial accidents. In this investigation, we designed a o‐phenylenediamine‐pyronin linked dye that is capable of both fluorogenic and colorimetric discrimination between phosgene and the prototypical nerve‐agent mimic, diethyl chlorophosphate (DCP) in the solution or gas phase. Moreover, this dye has been used to construct a portable kit that can be employed for real‐time monitoring of DCP and phosgene in the field, both in a discriminatory manner, and in a simple and safe way.

Phosphorylation of betti base with diethyl chlorophosphate

Phosphoric acid derivatives containing chiral Betti base fragment were synthesized by reacting racemic and enantiopure N-Boc-protected 1-(α-aminobenzyl)-2-naphthols with diethyl chlorophosphate followed by deprotection.

Relay recognition of F−and a nerve-agent mimic diethyl cyano-phosphonate in mixed aqueous media: discrimination of diethyl cyanophosphonate and diethyl chlorophosphate by cyclization induced fluorescence enhancement

F−to DCNP detection by relay recognition has been designed and realized for the first time with sequence specificity (F−→ DCNP)viaa fluorescence “off–on–on” mechanism.