Phosphoric Triamide Research Articles

Effects of inhibitors and slit incorporation on NH3 and N2O emission processes after urea application

The use of urea fertilizers in agriculture is associated with many negative environmental impacts and is a source of ammonia (NH3) and nitrous oxide (N2O) emissions. Such losses from urea fertilizer can be avoided by different mitigation techniques. Three different mitigation principles, urease inhibitor (N-(2-Nitrophenyl) phosphoric triamide, 2-NPT) (UI) alone and urease inhibitor in combination with nitrification inhibitors (N-[3(5)-methyl-1 H-pyrazol-1-yl) methyl] acetamide, MPA) (NI) and closed slit incorporation of urea fertilizer into the soil, were compared on a sandy loam soil at a soil water level of 70 % water-holding capacity. An in vitro microcosm approach with open dynamic incubation chambers was used to monitor NH3 emissions over two weeks with NH3 sampling by washing bottles. N2O emissions were studied over ten weeks in slow throughflow mesocosms with continuous gas chromatographic (GC) measurements. To get insights into N2O production and consumption processes, gas samples were taken after six weeks and N2O isotopocules were analyzed by isotope ratio mass spectrometry (IRMS). Slit injection showed the greatest effect on NH3 emission reduction by 79.6 % (40.6 % by UI, and 46.7 % by UINI) compared to surface applied urea. Minor pollution swapping to N2O was observed at the beginning of the trial due to incorporation but not in the cumulative emissions over the entire incubation time. The reduction effect of UINI on N2O emissions decreased over time with no cumulative emission reduction at the end of experimentation. N2O isotopocules confirmed the high contribution of nitrification to N2O production. In contrast and bacterial denitrification, nitrifier denitrification and fungal denitrification were involved on a much lower level and N2O reduction to N2 was not pronounced. All NH3 mitigation measurements where effective to decrease NH3 emissions while their effects on N2O emission varied over time. Factors as crop N uptake and rainfall would further modify the overall effect on N2O emissions and need to be considered for final pollution swapping assessment. Further research on the impact of NI on non-target microbial communities is warranted to elucidate potential environmental consequences and long-term efficacy of inhibitor compounds.

Field efficacy of urease inhibitors for mitigation of ammonia emissions in agricultural field settings: a systematic review

Globally, ammonia (NH3) is one of the key air pollutants and reducing NH3 emissions and the associated indirect emission of the greenhouse gas nitrous oxide remains challenging for the agricultural sector. During the past three decades, a number of urease inhibitors have been placed on the market with the goal of reducing NH3 loss from urea containing fertilisers. N–(n-butyl) thiophosphoric triamide (NBPT), N–(2-nitrophenyl) phosphoric triamide (2-NPT), a 3:1 ratio of NBPT + N-(n-propyl) thiophosphoric triamide (NPPT) and the maleic and itaconic acid co-polymer (MIP) are registered urease inhibitors under the European Commission Fertilising Products Regulation (FPR). However, the availability of several inhibitor options has raised questions from farmers, policymakers and emissions inventory compiling authorities regarding the field efficacy of the different options available for reducing NH3 loss. Despite many disparate NH3 field studies existing for NBPT, 2-NPT, NBPT + NPPT and MIP there is presently no review that brings these results together, a significant and important knowledge gap. This review addresses the gap by summarising the published field trial literature on NH3 volatilisation mitigation offered by NBPT, 2-NPT, NBPT + NPPT and MIP. Our review identified 48 peer reviewed studies where NH3 loss mitigation was measured in a field setting, giving 256 replicated comparisons. The synthesised literature results revealed that NBPT + NPPT reduced NH3 loss by 75% (95% CI = 58–82% n = 32), 2-NPT reduced NH3 loss by 70% (95% CI = 63–76% n = 19) and NBPT reduced NH3 loss by 61% (95% CI = 57–64% n = 165), giving on average a 69% reduction by these three urease inhibitors. In contrast, MIP increased NH3 loss by 0.3% on average (95% CI = −8–9% n = 40). The results presented in this review broaden the understanding of urease inhibitor efficacy in field conditions and demonstrate that not all products behave the same in terms of field NH3 reduction efficacy. This review is important for farmers, policymakers, emission inventory compilers and other stakeholders.

Supramolecular assembly mediated through NH···OX (X = C, N, P) hydrogen bonds and Y···π (Y = Br, π) contacts: Structural/computational studies of the P(O)(NHC(O)C6H4-3-NO2)(NHC6H4-3-Br)2 phosphoric triamide

Supramolecular assembly is studied in the structure of N,N'-bis(3‑bromo-phenyl)-N"-(3-nitro-benzoyl)phosphoric triamide, P(O)(NHC(O)C6H4-3-NO2)(NHC6H4-3-Br)2, I, by X-ray crystallography combined with quantum chemical calculations. The asymmetric unit of I is composed of two symmetry-independent molecules that show differences in some torsion angles, especially the ones related to the rotation of amine moieties. The conformations of amine moieties in two molecules are considered based on the resembling P—N—C—C/OP—N—C torsion angles, which associate with the ±sp/+sc conformations in one molecule and –sc/+sp and –sp/–sc conformations in the other molecule (sp = synperiplanar and sc = synclinal). In the crystal structure, the molecules are connected through N—H···OX (X = P, C, N) hydrogen bonds, forming a two-dimensional architecture along the bc plane. The C—H···O/π···π interactions do not change the dimensionality made by N—H···O hydrogen bonds, while the participation of Br···π interactions creates a three-dimensional network. The title structure represents the first observation of Br···π interaction in the C(O)NHP(O)-based family. The methods of Atoms in Molecules (AIM), Natural Bond Orbital (NBO) and Reduced Density Gradient (RDG) are used for the study of noncovalent interactions.

N-Triflyl Phosphoric Triamide (N-TPT) as an Efficient Activator for ‘On-Water’ Accelerated Aquacatalytic Polar Substrate Allylation

AbstractThe development of sustainable, functional-group-tolerant catalysis is highly significant from the perspectives of safety, user-friendliness, and cost-effectiveness. We report herein the triple hydrogen-bonding donor activator N-triflyl phosphoric triamide ( N-TPT) for the synergistic Brønsted acid aquacatalysis of multicomponent allylation ‘on-water’. The reaction demonstrated remarkable efficiency in converting polar diol substrate, such as 1,3-dihydroxyacetone, into α-tertiary amine derivative incorporating homoallylic amine functionalities using bulk water as the reaction medium. The single crystal X-ray structure and control experiments highlighted the crucial role of multiple hydrogen bonds in enabling this aqueous reaction.

Structural and photoluminescence properties of lanthanide (III) complexes with carbacylamidophosphate ligand and α,α′-bipyridine

Two series of lanthanide coordination compounds, [Ln(NO3)(L)2(bipy)] and [Ln(L)3(bipy)], where Ln3+ = Eu, Gd, Tb, with the carbacylamidophosphate CAPh ligand N,N,N′,N′-tetraethyl-N″-(trichloroacetyl) phosphoric triamide HL = Cl3CC(O)N(H)P(O)(NEt2)2 and α,α’-bipyridine, were synthesized. The complexes were characterized using infrared, ultraviolet diffuse reflection, and luminescence spectroscopy, as well as elemental and X-ray analyses. The bidentate coordination of the deprotonated CAPh ligand was confirmed through the analysis of the complexes' IR spectra and by X-ray analysis of the bis-CAPh Eu(III) and Tb(III) complexes. The emission and excitation solid-state spectra of the Eu(III) and Tb(III) complexes, as well as the f → f luminescence decay times, were measured at room temperature. Phosphorescence spectra of the Gd(III) complexes were measured at 77 K. The lowest ligands’ triplet state energy depends on the number of coordinated CAPh ligands in the complexes. The Eu(III) and Tb(III) compounds exhibited a strong metal-centered emission with decay times ranging from 1.72 ms to 2.3 ms. Intrinsic quantum yields (QLnLn) equal 82 % for [Eu(NO3)(L)2(bipy)] and 70 % for [Eu(L)3(bipy)]. The Tb(III) complexes revealed a very efficient ligand-to-metal energy transfer at room temperature.

Structural, Hirshfeld surface and molecular docking studies of a new organotin(IV)-phosphoric triamide complex and an amidophosphoric acid ester proposed as possible SARS-CoV-2 and Monkeypox inhibitors

Phosphoramides and their complexes are attractive compounds due to their significant inhibiting functionality in biological medicine. In this paper, a novel organotin(IV)-phosphoramide complex (Sn(CH3)2Cl2{[(3-Cl)C6H4NH]P(O)[NC4H8O]2}2, 1), derived from a reaction between phosphoric triamide ligand with dimethyltin dichloride, and a new amidophosphoric acid ester ([OCH2C(CH3)2CH2O]P(O)[N(CH3)CH2C6H5], 2), prepared from the condensation of a cyclic chlorophosphate reagent with N-methylbenzylamine, are structurally characterized and in silico investigated as potential SARS-CoV-2 and Monkeypox inhibitors by molecular docking simulation. Both compounds crystallize in the monoclinic crystal system with space group P21/c. The asymmetric unit of the complex 1 consists of one-half molecule, where SnIV is located on an inversion center, while the asymmetric part of 2 consists of one whole molecule. In the complex 1, the tin atom adopts a six-coordinate octahedral geometry with trans groups of (Cl)2, (CH3)2 and (PO)2 (PO = phosphoric triamide ligand). The molecular architecture consists of the N–H⋯Cl hydrogen bonds stretching as a 1D linear arrangement along the b axis with intermediate R22(12) ring motifs, whereas in the case of 2, the crystal packing is devoid of any classical hydrogen bond interaction. Furthermore, a graphical analysis by using Hirshfeld surface method identifies the most important intermolecular interactions being of the type H⋯Cl/Cl⋯H (for 1) and H⋯O/O⋯H (for 1 and 2), covering the hydrogen bond interactions N–H⋯Cl and C–H⋯O═P, respectively, which turn out to be favoured. A biological molecular docking simulation on the studied compounds provides evidence to suggest a significant inhibitory potential against SARS-COV-2 (6LU7) and Monkeypox (4QWO) especially for 6LU7 with a binding energy around −6 kcal/mol competing with current effective drugs against this virus (with a binding energy around −5 and −7 kcal/mol). It is worth noting that this report is the first case of an inhibitory potential evaluation of phosphoramide compounds on Monkeypox.

The fate of nitrification and urease inhibitors in simulated bank filtration

The application of nitrification and urease inhibitors (NUI) in conjunction with nitrogen (N) fertilizers improves the efficiency of N fertilizers. However, NUI are frequently found in surface waters through leaching or surface runoff. Bank filtration (BF) is considered as a low-cost water treatment system providing high quality water by efficiently removing large amounts of organic micropollutants from surface water. The fate of NUI in managed aquifer recharge systems such as BF is poorly known. The aim of this work was to investigate sorption and degradation of NUI in simulated BF under near-natural conditions. Besides, the effect of NUI on the microbial biomass of slowly growing microorganisms and the role of microbial biomass on NUI removal was investigated. Duplicate sand columns (length 1.7 m) fed with surface water were spiked with a pulse consisting of four nitrification (1,2,4-triazole, dicyanodiamide, 3,4-dimethylpyrazole and 3-methylpyrazole) and two urease inhibitors (n-butyl-thiophosphoric acid triamide and n-(2-nitrophenyl) phosphoric triamide). The average spiking concentration of each NUI was 5 μg/L. Experimental and modeled breakthrough curves of NUI indicated no retardation for any of the inhibitors. Therefore, biodegradation was identified as the main elimination pathway for all substances and was highest in zones of high microbial biomass. Removal of 1,2,4-triazole was 50% and n-butyl-thiophosphoric acid triamide proved to be highly degradable and was completely removed after a hydraulic retention time (HRT) of 24 h. 50% of the mass recovery for nitrification inhibitors except for 3,4-dimethylpyrazole was observed at the effluent (4 days HRT). In addition, a mild effect of NUI on microbial biomass was noted. This study highlights that the degradation of NUI in BF depends on HRT and microbial biomass.

Targeting yield and reducing nitrous oxide emission by use of single and double inhibitor treated urea during winter wheat season in Northern Germany

Nitrous oxide (N2O) is a powerful greenhouse gas and has an adverse effect on stratospheric ozone. Field application of synthetic N fertilizers is the largest source of global N2O emission and different N forms (nitrate vs. ammoniacal N) may play a significant role. In addition, the use of nitrification inhibitor (NI) is considered as a reliable way to mitigate agricultural N2O emission, whereas this effect is still debated for urease inhibitors (UI). However, the efficacy of NI or UI is still variable among different inhibitor products and environmental conditions. This study was conducted to test the efficacy of N form (calcium ammonium nitrate CAN vs. urea) and the almost unstudied UI, N-(2-nitrophenyl) phosphoric triamide (2-NPT), as well as an NI, mixture of dicyandiamide and 1H-1,2,4-triazol (DCD/TZ) and the combination of both inhibitors on N2O emission and crop yield. The measurements were carried out in winter wheat growth season in the subsequent years of 2012–2013 in the North of Germany. No difference in cumulated N2O emissions were observed between urea and CAN. The results confirmed the positive effect of NI (DCD/TZ) on reducing N2O emission. Compared with untreated urea, NI addition caused ∼75 % reduction of fertilizer derived N2O emissions within the vegetation period. The combination of UI and NI did not result in a further reduction of relative or yield-scaled N2O emission, although it resulted in higher grain yield and nitrogen recovery. Addition of UI showed no consistent effect on N2O emission compared to untreated urea, however in year 2013 a significant reduction of fertilizer derived emissions by ∼50 % was observed. Higher yields were observed for CAN fertilization compared to urea, though not significant. For both treatments including UI the yield effects, in particular N use efficiency, were stronger than for untreated urea and urea solely treated with NI. Therefore, the combined treatment with UI and NI was the most advantageous fertilizer solution for concomitantly achieving high yield, high nitrogen utilization efficiency and N2O emission reduction.

Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study

Urea granule dissolution in soil and soil urease activity are essential parameters for the accurate prediction of nitrogen dynamics after urea application, but both are scarcely studied. The response of urease activity to temperature is unclear under the addition of urease or nitrification inhibitors. In this study, we conducted laboratory incubation trials using glass jars with 100 g soil to quantify urea granule dissolution. Urease activity after urease and nitrification inhibitor addition were investigated in plastic bottles (5 g soil) under different temperatures. Inhibitor N-(2-nitrophenyl) phosphoric triamide (2-NPT), and a mixture of dicyandiamide and 1 H-1,2,4-triazol (DCD/HZ) were tested as urease and nitrification inhibitors separately and in combination. The dynamics of urease activity was fitted with Michaelis–Menten kinetics combined with the Van’t Hoff equation. At low soil moisture contents close to air-dry conditions (4–8% w/w water content), soil moisture was the dominant factor, but at higher soil moisture contents (28% and 48% w/w), temperature controlled the dissolution process. Dissolution could take several days or even longer at very dry soil conditions, while it was completed between a few hours and 24 h at high soil moisture levels. Urea with urease inhibitor formulation dissolved significantly slower at a moisture level of 28% (w/w). In the studied soil, urease activity varied between 2.9 and 54.4 mg NH4+-N kg−1 h−1. Across all urea concentrations, the addition of urease inhibitor 2-NPT significantly reduced urease activity. The relationship between urease activity and urea addition rate could be accurately described with Michaelis–Menten kinetics, and urease inhibitor addition reduced the temperature sensitivity of urease activity by 7%, while the nitrification inhibitor increased it by 4%. Parameter estimates and process characterization for urea granule dissolution and urea hydrolysis in this study are meaningful for and helpful in agricultural practice and the model simulation of soil nitrogen dynamics.

Different phosphoric triamide [HN]3-nP(O)[N]n (n = 1, 2) skeletons lead to identical non-covalent interactions assemblies: X-ray crystallography investigation, Hirshfeld surface analysis and molecular docking study against SARS-CoV-2

In this work, we describe the crystal structures of two new phosphoramides containing the same [(3-Cl)C6H4NH]P(O) = Y segment (Y[N(CH3)CH2C6H5]2 (1) and Y[NC4H8O]2 (2)) and an improved model of [C6H11(CH3)N]P(O)[NHC(CH3)3]2 (compound 3). The structures are experimentally investigated by single crystal X-ray diffraction using two types of refinements with spherical (S) and aspherical (AS) [Hirshfeld atomic refinements (HARs)] form factors, FT-IR and 1H, 13C, 31P NMR spectroscopy. A biological molecular docking investigation gives hints to suggest an appropriate inhibitory activity against MPro of SARS-COV-2 (6M03 and 6LU7) especially for 1 with a binding energy around −6 (6M03)/−7 (6LU7) kcal/mol. In the present work, the docking simulations are carried out for the first time for three series of ligand (L)-protein (P) complexes: L (with S form)-P (6M03), L (with AS form)-P (6M03) and L (AS)-P (6M03-N, with hydrogen atoms at their theoretical neutron values), where the binding energies are approximately proved to be 0.8 kcal/mol lower for simulations with 6M03-N than those for 6M03. Moreover, the structural study illustrates that the hydrogen bond patterns of all three structures consist of one-dimensional zigzag chains formed by classical NH…O hydrogen bond interactions. Further stabilization is provided by weak interactions such as CH…Cl (for 1 and 2), Cl…π (for 1 and 2) and CH…O (for 2 and 3). Furthermore, the intermolecular interactions are analyzed by three-dimensional (3D) Hirshfeld surfaces, 2D fingerprint plots and enrichment ratios. The favored contacts identified by Hirshfeld surface analysis are H…O/O…H interactions covering the NH…O hydrogen bonds for all three structures. For 1 and 2, Cl…C/C…Cl contacts covering Cl…π interactions are recognized as the most enriched contacts.

Major metabolites of NBPT degradation pathways contribute to urease inhibition in soil.

Urea is the most commonly used nitrogen fertilizer worldwide. However, depending on soil and environmental conditions, high nitrogen losses can occur due to gaseous ammonia emissions. Urease inhibitors like N-(n-butyl)thiophosphoric triamide (NBPT) reduce these losses by blocking the urease enzyme, which catalyzes urea hydrolysis. With the increasing use of NBPT its environmental fate and features of urease inhibition become increasingly important. This study aimed to further elucidate major NBPT degradation pathways and related urease inhibition in soil. This was investigated in a 14-d incubation experiment using practice-relevant application rates of NBPT and four of its metabolites N-(n-butyl)phosphoric triamide (NBPTO), diamido phosphoric acid (DAP), diamido thiophosphoric acid (DATP) and rac-N-(n-butyl)thiophosphoric diamide (NBPD), covering three postulated degradation pathways. Additionally, the urease inhibition by these compounds was determined and further investigated in 2-h tests. The latter provided dose-response curves, showing that all substances inhibited urease, with NBPTO being the most effective. Inhibition of urease in NBPT-spiked soil was also largely, but not completely, attributed to NBPTO formed within the test period. In 14-d incubation tests, all investigated compounds dissipated quickly by >90% within 6d (NBPTO), 3d (NBPT) and ≤1d (DAP, DATP and NBPD). Extensive oxidation of NBPT to NBPTO and subsequent minor formation of DAP was identified as the preferred degradation pathway. Abiotic degradation processes in sterile soil corresponded to 65-90% of total degradation in microbial active soil. Furthermore, pseudo-first order dissipation kinetics were retarded in sterile soil. Urease activity, calculated as a percentage of activity in the urea-fertilized control, was lowest after about 2d when NBPTO was spiked to soil (17.9%), followed by NBPT (35.7%), DATP (51.3%), NBPD (54.0%), and DAP (54.4%). This shows that urease inhibition depends on the interplay of NBPT and its degradation products.

Effect of SBA-15-based immobilization of a new phosphoric triamide Ag (I) complex on its catalytic activity: Synthesis, characterization, crystallography and catalytic investigation

A new Ag (Ⅰ) complex (C) containing phosphoric triamide ligand (L) with a formula of [Ag ((C5H4NC (O) NHP (O) (NC6H12)2)2NO3] 2 was synthesized by the reaction of AgNO3 with N-nicotinyl –N′, N″-bis (hexamethylenyl) phosphoric triamide. The complex (C) was characterized by Fourier transform infrared spectroscopy (FT-IR), molar conductivity, thermal gravimetric analysis (TGA), and X-ray crystallography techniques. Results showed that complexation occurred via the nitrogen atom of the pyridine ring. The molecular structure of C, refined from single-crystal X-ray diffraction, is triclinic with a P-1 space group. The complex was immobilized on SBA-15 and the produced compound (C@SBA-15) was identified by BET, AAS, FT-IR, XRD, and TGA methods. Successful loading of the complex on SBA-15 was determined by the BET method. According to AAS findings, the amount of silver in the C@SBA-15 composition was 18%. FT-IR and XRD results showed that the complex was absorbed on the support physically and the hexagonal structure of the support was retained after immobilization. Thermal stability of C@SBA-15 was confirmed by TGA analysis. The homogeneous complex (C) and heterogeneous C@SBA-15 were used as catalysts in the oxidation reaction of aromatic aldehydes and sulfides and their catalytic properties compared. H2O2 was used as a green oxidant, some effective parameters (reaction temperature, substrate to oxidant molar ratio, catalyst amount, and solvent type) were optimized, and the conversion percentages of 70% (for C catalyst) and 50% (for C@SBA-15 catalyst) obtained. The reusability of C@SBA-15 and the generality of both catalysts were evaluated and confirmed. The results showed that when the complex was immobilized on SBA-15, its catalytic efficiency decreased, and its recoverability increased. A comparison with other published reports showed that the catalytic efficiency of the catalysts in the oxidation reaction of aldehydes and sulfides was within acceptable limits.

Energy frameworks and Hirshfeld surface analysis of supramolecular features in three new phosphoric triamides: tuning the intermolecular interactions via the substituent effect

Supramolecular features observed in the crystal structures of phosphoric triamides are mostly influenced by strong hydrogen bond interaction N—H...OP. With the aid of substituent groups a scenario can be created where the crucial role of weak interactions towards the stabilization of the overall molecular packing, in the absence of any strong interaction can be evaluated more reliably. In this context, we have studied the supramolecular features of three new phosphoric triamides 1 – 3, with [NH]P(O)[N]2, [C(O)N]2P(O)[N] and [C(O)N]2P(O)[NH] segments, respectively. The compounds crystallize in the monoclinic space groups P21/c for 1 and 2 with one phosphoric triamide molecule and in P21 for 3 with two molecules in the asymmetric unit. The intermolecular interactions and their energies are evaluated using Hirshfeld surface and energy framework analyses revealing that the presence or absence of substituent groups such as 2-oxo-3-oxazolidinyl may serve as a crucial cohesive factor in the supramolecular assembly. The substituent alters the intermolecular interaction contributions, with subsequent changes in the formation of different weak interactions and molecular assemblies. The structure of 2 bearing this substituent displays the highest energy interaction without any strong interaction. The crystal packing is stabilized by a variety of interactions involving the weak hydrogen bonds with the PO and CO acceptor sites. The effects of substituent groups on the molecular frameworks formed by various intermolecular interactions are analyzed in detail via energy framework diagrams. Finally, a biological study by the molecular docking method indicates that the studied here compounds could be appropriate candidates as SARS-CoV-2 inhibitors.

Experimental and theoretical study of novel amino-functionalized P(V) coordination compounds suggested as inhibitor of MPro of SARS-COV-2 by molecular docking study.

Amino‐functionalized P(V) derivatives providing both N‐ and O‐donor modes have attracted interest owing to their potential to form interesting coordination assemblies with applications such as biological drugs. Novel coordination modes of two‐ and four‐dentate tris (pyridin‐2‐yl)phosphoric triamide OP[NH‐2Py]3 as ([Co(II){[O][NH‐2Py]P(O)[Ph]}2(DMF)2], 1) and ([Cu(II)Cl{[NH‐2Py]2P(O)[N‐2Py]}].DMF, 2) have been synthesized and structurally studied. The metal center environment is distorted octahedral for 1 and distorted square pyramidal for 2. The crystal structure of a new complex of Cu(II) with a Cu[N]4[Cl]2 environment ([Cu(II)Cl2(Pyrazole)4], 3) is also investigated. An evaluation of the inhibitory effect against the coronavirus (Main Protease [MPro] of SARS‐CoV‐2) was carried out by a molecular docking study and illustrates that these compounds have a good interaction tendency with CoV‐2, where 1 has the best binding affinity with the biological target comparable with other SARS‐CoV‐2 drugs. Moreover, theoretical QTAIM and natural bond orbital (NBO) calculations are used to evaluate the metal‐oxygen/‐nitrogen bonds suggesting that they are mainly electrostatic in nature with a slight covalent contribution. A molecular packing analysis using Hirshfeld surface (HS) analysis shows that N—H … O (in 1 and 2) and N—H … Cl (in 3) hydrogen bonds are the dominant interactions that contribute to the crystal packing cohesion. The semi‐empirical PIXEL method indicates that the electrostatic and repulsion energy components in the structures of 1 and 2 and the dispersion and electrostatic components in that of 3 are the major contributors to the total lattice energy.

N-Triflyl Phosphoric Triamide: A High-Performance Purely Organic Trifurcate Quartz Crystal Microbalance Sensor for Chemical Warfare Agent.

G-, V-, and A-series nerve agents are extremely toxic organophosphorus chemical warfare agents (CWAs) that incorporate P═O functional groups. Their colorless, tasteless, and odorless nature makes rapid and efficient detection challenging. Here, we report an unprecedented N-triflyl phosphoric triamide (N-TPT) receptor, which is a new class of triple hydrogen bonding donor molecular sensors for CWA recognition via noncovalent host-guest-type interactions. The highly robust trifurcate structures were designed based on density functional theory (DFT) computations and synthesized from N-triflyl phosphorimidoyl trichloride by simple stepwise processes. Quartz crystal microbalance (QCM) analysis allowed robust detection of typical CWA simulants, such as dimethyl methylphosphonate. The concentration-dependent QCM profiles were fitted with the Sips isotherm model, revealing that the thermodynamic parameters of the binding behaviors are roughly correlated with the calculated results. Developed N-TPT receptors show higher binding abilities than previously reported receptors and reasonable selectivity over other volatile compounds.

Synthesis and structural study of five new phosphoric triamides: interplay between classical and non-classical intermolecular interactions

Abstract Phosphoric triamides are attractive to investigate because of their extensive applications in various fields, especially in medicine. Five new phosphoric triamides with the main parts [N]P(O)[NH]2 and [C(O)NH]P(O)[N]2 have been structurally analyzed by single crystal MoKα/synchrotron-based X-ray diffraction and characterized by spectroscopic methods (FT-IR and 1H, 13C, 31P NMR). Compounds crystallize in orthorhombic (1 with space group Pnma) and monoclinic (2 (P21/a), 3 (C2/c), 4 (P21/n) and 5 (P21/c)) crystal systems. The asymmetric unit of all structures consists of one phosphoric triamide molecule, except for 1 with one half of molecule. X-ray crystallography data reveal that the molecular architectures constructed by classical N—H … O hydrogen bonds are as 1D linear (building the R 2 1 ( 6 ) ${R}_{2}^{1}\left(6\right)$ , C(4) and R 2 2 ( 10 ) / R 2 1 ( 6 ) ${R}_{2}^{2}\left(10\right)/{R}_{2}^{1}\left(6\right)$ motifs, respectively, for 1–3) or dimeric (the R 2 2 ( 8 ) ${R}_{2}^{2}\left(8\right)$ ring motif for 4 and 5). A detailed investigation of the intermolecular interactions using Hirshfeld surface (HS) analysis illustrates that the H … H, O … H/H … O and C … H/H … C contacts for all compounds, and Cl … H/H … Cl and F … H/H … F contacts for 3–5, are the most significant contributors to the crystal packing. Moreover, based on the calculated enrichment ratios (E), the O … H/H … O contacts including the classical N—H … O hydrogen bonds for all structures are considered as favoured contacts.

Synthesis of phosphoric triamide nanostructures, characterization, X-ray crystallography, and preparation of P2O5-RGO nanocomposites by solvothermal method

Rod-shaped and hexagon-like nanostructures of a phosphoric triamide 4-NO2C6H4C(O)NHP(O)(NHC(CH3)3)2 have been prepared by a sonochemical method and a microwave process, respectively. The new nano-structures were characterized by SEM, XRD, UV–vis, infrared spectroscopy, and elemental analyses. The crystal structure of compound showed a distorted tetrahedral geometry for phosphorus with anti-configuration for the P(O) and C(O) groups respect to each other. Non-covalent interactions, that is, hydrogen bonding, stacking, and CH…HC contacts connected the chains into a 3D framework. Thermal stability in single crystalline and nano-scale was carried out by TGA and DSC. Further, P2O5 nanosphericals have been prepared from a precursor nano-rod phosphoric triamide at 750 °C with a diameter of 30–40 nm. P2O5 nanoparticles have been decorated from a single source precursor phosphoramide, 4-NO2C6H4C(O)NHP(O)(NHC(CH3)3)2, onto reduced graphen oxide surfaces by a solvothermal approach. Decorated nanoparticles have an orthorhombic phase with a sphere-like morphology and average size of 10–20 nm.

HMPA-Free Generation of Trialkylsilyllithium Reagents and Its Applications to the Synthesis of Silylboronic Esters

AbstractTrialkylsilyllithium species have turned out to be facilely generated by treating hexaalkyldisilanes with methyllithium in the presence of tris(N,N-tetramethylene)phosphoric triamide (TPPA) as an activator, which can be trapped by boron electrophiles to afford silylboronic esters including long-awaited Me3Si–B(pin).

Development of One-Step Non-Solvent Extraction and Sensitive UHPLC-MS/MS Method for Assessment of N-(n-Butyl) Thiophosphoric Triamide (NBPT) and N-(n-Butyl) Phosphoric Triamide (NBPTo) in Milk.

N-(n-butyl) thiophosphoric triamide (NBPT) is a urease inhibitor utilised in urea-based fertilizers. In Ireland, fertilizer treated with NBPT is applied to pasture to mitigate both ammonia and nitrous oxide emissions, but concerns arise as to the potential for residues in milk products. A quick ultrafiltration extraction and ultra-high performance liquid chromatography coupled with mass spectrometry triple quadrupole (UHPLC-MS/MS) quantitation method was developed and validated in this study. The method was applied in the analysis of samples collected from a field study investigating potential transfer of NBPT residues into milk. NBPT and NBPTo residues, were extracted from fortified milk samples and analysed on a UHPLC-MS/MS with recoveries ranging from 74 to 114%. Validation of the UHPLC-MS/MS method at low (0.0020 mg kg−1) and high (0.0250 mg kg−1) concentration levels in line with SANTE/12682/2019 showed overall trueness in the range of 99 to 104% and precision between 1 and 10%, RSD for both compounds. The limit of quantitation (LOQ) was 0.0020 mg kg−1 and other tested parameters (linearity, sensitivity, specificity, matrix effect, robustness, etc.) satisfied acceptance criteria. Stability assessment using spiked samples revealed the compounds were stable in raw and pasteurised milk for 4 weeks at –80 °C storage temperature. Maintaining samples at pH 8.5–9.0 further improved stability. Analysis of 516 milk samples from the field study found that NBPT and NBPTo concentrations were below the LOQ of 0.0020 mg kg−1, thus suggesting very low risk of residues occurring in the milk. The method developed is quick, robust, and sensitive. The method is deemed fit-for-purpose for the simultaneous determination of NBPT and NBPTo in milk.

Structural differences/similarities of diastereotopic groups in three new chiral phosphoramides.

The crystal structures of two single-enantiomer amidophosphoesters with an (O)2P(O)(N) skeleton and one single-enantiomer phosphoric triamide with an (N)2P(O)(N) skeleton were studied. The compounds are diphenyl [(R)-(+)-α-4-dimethylbenzylamido]phosphate, (I), and diphenyl [(S)-(-)-α-4-dimethylbenzylamido]phosphate, (II), both C21H22NO3P, and N-(2,6-difluorobenzoyl)-N',N''-bis[(R)-(+)-α-ethylbenzyl]phosphoric triamide, C25H28F2N3O2P, (III). The asymmetric units contain two amidophosphoester molecules for (I) and (II), and one phosphoric triamide molecule for (III). In the crystal structures of (I) and (II), molecules are assembled in a similar one-dimensional chiral ribbon architecture, but with almost a mirror-image relationship with respect to each other through N-H...O(P) and C-H...O(P) hydrogen bonds along [010]. In the crystal structure of (III), the chiral tape architecture along [100] is mediated by N-H...O(P) and N-H...O(C) hydrogen bonds, and the tapes are connected into slabs by C-H...O interactions (along the ab plane). The differences/similarities of the two diastereotopic phenoxy groups in (I)/(II) and the two chiral amine fragments in (III) were studied on the grounds of geometry, conformation and contribution to the crystal packing, as well as 1H and 13C signals in a solution NMR study.