Spectrophotometric Studies of Dissociation Constants of Nitroguanidines, Triazoles and Tetrazoles

DeVries, John E.; Gantz, E. St. Clair

doi:10.1021/ja01633a019

Cited by 28 publications

(9 citation statements)

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“…In addition to these competing reductions of nitro- and nitrosoguanidine is the complication of the low solubility of both the starting material and its first reduction product. Thiele describes an acid/base workup that can be used to separate nitro- and nitrosoguanidine and exploits the latter’s relative basicity with a p K b of 11.90 . The reduction of nitroguanidine with Pt/H 2 has been reported, but again the over-reduction to aminoguanidine is a significant side product. , In addition to these difficulties, the conditions for zinc reduction in water used for nitrosoguanidine cannot be generalized to other alkylnitroguanidines.…”

Section: Resultsmentioning

confidence: 99%

2,3,5-Metallotriazoles: Amphoteric Mesoionic Chelates from Nitrosoguanidines

et al. 2021

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Soluble nitrosoguanidine- and N-methylnitrosoguanidine-based metallotriazole complexes of ruthenium(II) monocarbonyls have been prepared and characterized. Both nitrosoguanidines prove to be strong chelates with the formally π-accepting nitroso nitrogen binding cis to carbon monoxide and a π-donating amide trans to the CO. The resulting ensemble consists of ruthenium examples of 1-metallo-2,3,5-triazoles. The ruthenium coordination sphere is completed by anions, either H–, Cl–, or Ph–, trans to the nitroso group as well as two mutually trans PPh3 groups. The π-donating amide group is formally sp2 hybridized with a planar nitrogen to give a strongly bound five-membered chelating anion. Together, these results illustrate the remarkable potential for the nitrosoguanidinates as a family of new metal chelates.

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Section: Resultsmentioning

confidence: 99%

2,3,5-Metallotriazoles: Amphoteric Mesoionic Chelates from Nitrosoguanidines

et al. 2021

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“…Furthermore, PA, NTO, and 2,4-DNP exist as anions at neutral pH due to their acidic nature, with pKa = 0.38, 3.76, and 4.11, respectively. Alternatively, NQ (pKa 12.2) can exist as either a nitroimine (predominant at environmental pH) or nitroamine, and at very low pH could become protonated to form a cation (De Vries and St. Clair-Gantz 1954;Kaplan, Cornell, and Kaplan 1982). DNAN is the exception of the IM compounds, with water solubility comparable to TNT (approximately 200 mg/L) (Lide 2005).…”

Section: Introductionmentioning

confidence: 99%

Preparative, extraction, and analytical methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil or sediment, and tissue matrices

Crouch¹,

Smith²,

Stromer³

et al. 2021

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No standard method exists for determining levels of insensitive munition (IM) compounds in environmental matrices. This project resulted in new methods of extraction, analytical separation and quantitation of 17 legacy and 7 IM compounds, daughter products of IM, and other munition compounds absent from USEPA Method 8330B. Extraction methods were developed for aqueous (direct-injection and solid-phase extraction [SPE]), soil, sediment, and tissue samples using laboratory-spiked samples. Aqueous methods were tested on 5 water sources, with 23 of 24 compounds recovered within DoD QSM Ver5.2 limits. New solvent extraction (SE) methods enabled recovery of all 24 compounds from 6 soils within QSM limits, and a majority of the 24 compounds were recovered at acceptable levels from 4 tissues types. A modified chromatographic treatment method removed analytical interferences from tissue extracts. Two orthogonal high-performance liquid chromatography-ultraviolet (HPLC-UV) separation methods, along with an HPLC–mass spectrometric (HPLC-MS) method, were developed. Implementing these new methods should reduce labor and supply costs by approximately 50%, requiring a single extraction and sample preparation, and 2 analyses rather than 4. These new methods will support environmental monitoring of IM and facilitate execution of risk-related studies to determine long-term effects of IM compounds.

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“…NQ is highly soluble in water (4.4 g/L at 25 °C) and has a low soil–water partition coefficient of 0.15–0.43 L/kg. , In addition, NQ is not charged between pH −0.5 and 12.2, , and as such, it is highly mobile in aqueous systems and soils. Although the reduction of NQ can yield nitrosoguanidine, which was shown to be carcinogenic in rats, it is classified by the USEPA as a group D substance, i.e., a compound that is not classifiable as a human carcinogen…”

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confidence: 99%

Sensitive Analysis of Nitroguanidine in Aqueous and Soil Matrices by LC-MS

et al. 2017

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Nitroguanidine, a widely used nitramine explosive, is an environmental contaminant that is refractory, persistent, highly mobile in soils and aquifers, and yet under-researched. Nitroguanidine determination in water and soil poses an analytical challenge due its high hydrophilicity, low volatility, charge neutrality over a wide pH range, and low proton affinity which results in low electrospray interface (ESI)-MS sensitivity. A sensitive method for the determination of nitroguanidine in aqueous and soil matrices was developed. The method is based on reduction by zinc in acidic solution, hydrophobization by derivatization, preconcentration on C18 cartridge, and LC-MS quantification. The demonstrated limit of detection (LOD) reaches 5 ng/L and 22 ng/g in water and soil, respectively. Analysis of a contaminated site demonstrates that it is possible to map a contamination plume that extends over 1 km from the source of the contamination.

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Spectrophotometric Studies of Dissociation Constants of Nitroguanidines, Triazoles and Tetrazoles

Cited by 28 publications

References 0 publications

2,3,5-Metallotriazoles: Amphoteric Mesoionic Chelates from Nitrosoguanidines

2,3,5-Metallotriazoles: Amphoteric Mesoionic Chelates from Nitrosoguanidines

Preparative, extraction, and analytical methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil or sediment, and tissue matrices

Sensitive Analysis of Nitroguanidine in Aqueous and Soil Matrices by LC-MS

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