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The extraction and separation of Mo and V from sulphate media were investigated with phosphorus-based extractants such as D2EHPA, PC88A and Cyanex 272. The extraction was maximum within pH 1–3 and decreased after that pH. After pH 6.0, there was no extraction of Mo and V with the above extractants. The FTIR spectra indicated the bonding of hydroxyl group attached to phosphorus atom in each case which is due to the reaction of the cationic form of Mo ( $${\text{H}}_{3} {\text{MoO}}_{4}^{ + }$$ ) and V ( $${\text{VO}}_{2}^{ + }$$ ) with the extractants. The highest separation factor was obtained with PC 88A. Hence, PC 88A was used for the separation of Mo and V from sulphate leach liquor of hydrodesulphurization spent catalyst. The McCabe–Thiele plot with 0.5 M PC 88A indicated three stages at A/O ratio of 2:1. Vanadium was selectively stripped with 0.5% H2SO4 followed by Mo stripping with NH4OH + (NH4)2CO3.

A common feature of fluorescent sensing materials for detecting chemical warfare agents (CWAs) and simulants is the presence of nitrogen-based groups designed to nucleophilically displace a phosphorus atom substituent, with the reaction causing a measurable fluorescence change. However, such groups are also basic and so sensitive to acid. In this study we show it is critical to disentangle the response of a candidate sensing material to acid and CWA simulant. We report that pyridyl-containing sensing materials designed to react with a CWA gave a strong and rapid increase in fluorescence when exposed to Sarin, which is known to contain hydrofluoric acid. However, when tested against acid-free diethylchlorophosphate and di-iso-propylfluorophosphate, simulants typically used for evaluating novel G-series CWA sensors, there was no change in the fluorescence. In contrast, simulants that had been stored or tested under a standard laboratory conditions all led to strong changes in fluorescence, due to acid impurities. Thus the results provide strong evidence that care needs to be taken when interpreting the results of fluorescence-based solid-state sensing studies of G-series CWAs and their simulants. There are also implications for the application of these pyridyl-based fluorescence and other nucleophilic/basic sensing systems to real-world CWA detection. Chemical warfare agents and simulants are commonly detected with fluorescent sensing materials containing nitrogen-based groups, however these groups’ basicity can cause false positives in the presence of acids. Here, the authors disentangle the response of pyridyl-containing sensing materials to acid-containing and acid-free Sarin and simulants.

A phosphaguanidine [Me2NC(PPh2)=N i Pr], the analogous guanidine [Me2NC(NPh2)=N i Pr], and their hydrochloride (HCl) salts were prepared to study the influence of substituting a phosphorus atom for a nitrogen atom on the basicity of the two compounds and the bonding in their conjugate acids. The pK a values of both HCl salts were measured in acetonitrile by NMR titration. Surprisingly, the substitution of P for N has essentially no effect on basicity even though the geometry at that atom is changed. The presence of phenyl substituents in the protonated guanidine reduces the resonance in the CN3 core, whereas poor orbital overlap between P and C reduces the resonance in the N2CP core of the protonated phosphaguanidine. The neutral phosphaguanidine binds to a Cu(I) halide through both the Nimine and the P, which suggested that the basic N atom on the bound ligand may have little utility as a Brønsted base. Fortunately, however, a Cu(I) halide complex of the protonated phosphaguanidine is stable. Thus, the tendency of the basic N to bind to metals does not proscribe it serving as a metal-proximate Brønsted base.

Phosphines have played an important role in the rapid rise of transition metal-catalysed processes and with the possibility of fine-tuning the electronic and steric properties of these ligands, several synthesis challenges have been overcome in the past decades leading to their application in academia and industry. Caged phosphines are one such class of phosphines with the phosphorus atom at the bridgehead of a cyclic cage and have exhibited excellent control of the steric and electronic properties leading to their applications as ligands in a vast number of catalytic processes. This review provides an overview of the origin of this area of research, as well as the developments that have taken place and how the unique properties of these ligand systems could help to fine-tune the reactivity. A critical analysis of the area reveals some lacunae that will also be highlighted to promote further developments in this area of research.

The yet unknown 2-amino-substituted λ3 ,σ2 -phosphinines are phosphorus-containing aniline derivatives. Calculations show that the strong interaction of the π-donating NR2 group with the aromatic system results in a high π-density at the phosphorus atom. We could now synthesize 2-N(CH3 )2 -functionalized phosphinines, starting from a 3-N(CH3 )2 -substituted 2-pyrone and (CH3 )3 Si-C≡P. Their reaction with CuBr⋅S(CH3 )2 affords CuI complexes with the first example of a neutral phosphinine acting as a rare bridging μ2 -P-4e donor-ligand between two CuI centers. Our experimental and theoretical investigations show that 2-aminophosphinines are missing links in the series of known 2-donor-functionalized phosphinines.

Conformational analysis of tris(4-methylphenyl)phosphine and its oxide, sulfide, and selenide has been performed by the dipole moment method and DFT quantum chemical calculations at the B3PW91/ 6-311++G(df,p) level of theory. The title compounds have been found to exist in solution as a single symmetrical conformer with gauche,gauche,gauche orientation of the substituents on the phosphorus atom with respect to the P=X bond (X = LEP, O, S, Se).

Despite diamondoid phosphines have found many synthetic applications and are even available commercially the chemistry of chiral diamondoid phosphines remains largely unexplored. Aim . To develop the convenient preparative method for the preparation of sterically-congested P-stereogenic secondary diamodoidyl phosphines as potential organocatalysts and ligands in the asymmetric synthesis. Results and discussion . A convenient method for the synthesis of P-stereogenic diamondoid phosphines with high yields through the phosphorylation of hydroxydiamondoids in trifluoroacetic acid followed by the reduction of the corresponding asymmetric chlorophosphonates has been proposed. The secondary phosphines obtained form stable complexes with borane that can be used to separate diamondoid phosphines into enantiomers. Experimental part . The experimental procedures for the preparation of 1- and 4-diamantyl-1-adamantyl- and phenylphosphines were developed; the structures of new compounds were confirmed by NMR and HRMS spectral data. Conclusions . A number of P-stereogenic mixed diamondoidylaryl phosphines and the secondary phosphines containing exclusively diamondoid substituents has been prepared. A degree of steric bulkiness is determined by the combination of diamondoid substituents around a phosphorus atom where 1-diamantyl derivatives are the most sterically-congested. The compounds obtained are potential ligands in asymmetric catalysis. Received: 31.03.2020 Revised: 24.06.2020 Accepted: 27.08.2020

Thiophosphorus acids R1R2P(S)OH constitute an important class of organophosphorus compounds, in which the phosphorus atom is intrinsically chiral if R1 ≠ R2. In connection with a project aimed at the preparation of chiral thiophosphorus acids, various available literature methods were considered, but few fit the requirement of odorless reagents. Herein, the results of our studies on the synthesis of thiophosphinic acids are reported. Ultimately, two major approaches were selected: (1) the Stec reaction of phosphorus amides with carbon disulfide; and (2) the one-pot synthesis of thiophosphorus acids from H-phosphinates, an organometallic nucleophile, and quenching with elemental sulfur. An application to the preparation of a potential chiral phosphorus organocatalyst is also reported.

The phosphino groups in 1,3-diphosphacyclobutane-2,4-diyl in the singlet biradicaloid play important roles in determining the physicochemical characteristics of the particular open-shell phosphorus heterocycles. Herein, we demonstrate that the introduction of para-substituted phenyl groups to the phosphorus atom induces useful photoabsorption and redox characteristics, as confirmed by the Hammett equation. These findings provided reliable methods for realizing desirable physicochemical properties of the open-shell singlet phosphorus heterocyclic chromophores based on programmed tuning of the molecular orbital energy levels of the particular open-shell singlet (non-Kekulé) heterocyclic unit. In addition, use of the thiophene substituent allowed confirmation of the orbital tuning by catenation of the P-heterocyclic units, with theP-C

The chapter summarizes the development in the field of six-membered rings with one phosphorus atom in the period between 2008 and 2018. In this context, theoretical, structural, thermodynamic, and reactivity aspects of aromatic and non-aromatic phosphorus-based heterocycles are covered and discussed. ispartof: Comprehensive Heterocyclic Chemistry IV pages:685-717 ispartof: vol:7 pages:685-717 status: Published online

A propeller-like pyrene derivative of diphenyl-1-pyrenylphosphine (DPPP) is designed and synthesized. DPPP exhibits a unique photo-triggered AIE/ACQ transition with a remarkable third-order nonlinear optical signal change, which is proved to originate from the photo-induced oxidation of a phosphorus atom.

The reaction behavior of [Cp2Mo2(CO)4(μ,η2:2-P2)] (1) and [Cp''Ta(CO)2(η4-P4)] (2), respectively, towards the anions OH- and tBu- are reported. While the reaction of 1 with KOH gives the anionic complex [Cp2Mo2(CO)4(μ-PH2)]- (3) under a formal phosphorus atom abstraction, reaction with LitBu leads to the alkylation product [Cp2Mo2(CO)4(μ,η2:1-PPtBu)]- (4). The reactions of 2 with [IDipp-H][OH] ([IDipp-H]+ = 1,3-bis-(2,6-diisopropyl-phenyl)imidazolium) and LitBu yield [Cp''Ta(CO)2{η3-P4(O)H}]- (5) and [Cp''Ta(CO)2(η3-P4tBu)]- (6), respectively. Compounds 3, 4, 5 and 6 were comprehensively characterized by NMR spectroscopy and X-ray structure analysis.

A gold(I) complex with a 1,1′-binaphthyl-substituted diphosphene was synthesized and fully characterized. A phosphorus atom with a less-hindered binaphthyl group coordinates to a gold(I) moiety in ...

The structures and energetics of the binuclear phospholyl chromium carbonyl derivatives (C4H4P)2Cr2(CO)n (n = 6, 5, 4, 3) have been investigated by density functional theory. The lowest energy (C4H4P)2Cr2(CO)n (n = 6, 4, 3) structures are completely analogous to their Cp2Cr2(CO)n analogues with two terminal pentahapto phospholyl rings. However, for the pentacarbonyl (C4H4P)2Cr2(CO)5 the lowest energy structure has a bridging seven-electron donor η5,η1-C4H4P ligand using the phosphorus lone pair in addition to the π-system of the phospholyl ligand as well as a Cr-Cr single bond. Thus, except for the pentacarbonyl the phosphorus lone pair of the phospholyl ligand is seen to play a minor role in the energetically preferred structures of the binuclear phospholyl chromium carbonyl derivatives.

Mitochondrial dysfunction is an underlying pathology in numerous diseases. Delivery of diagnostic and therapeutic cargo directly into mitochondria is a powerful approach to study and treat these diseases. The triphenylphosphonium (TPP(+)) moiety is the most widely used mitochondriotropic carrier. However, studies have shown that TPP(+) is not inert; TPP(+) conjugates uncouple mitochondrial oxidative phosphorylation. To date, all efforts toward addressing this problem have focused on modifying lipophilicity of TPP(+)-linker-cargo conjugates to alter mitochondrial uptake, albeit with limited success. We show that structural modifications to the TPP(+) phenyl rings that decrease electron density on the phosphorus atom can abrogate uncoupling activity as compared to the parent TPP(+) moiety and prevent dissipation of mitochondrial membrane potential. These alterations of the TPP(+) structure do not negatively affect the delivery of cargo to mitochondria. Results here identify the 4-CF(3)-phenyl TPP(+) moiety as an inert mitochondria-targeting carrier to safely target pharmacophores and probes to mitochondria.

The proposed SN2 reactions of a hindered organophosphorus reactant with aliphatic and aromatic nucleophiles [Ye et al., Org. Lett. 19, 5384–5387 (2017)] were studied theoretically in order to explain the observed stereochemistry of the products. Our computations indicate that the reaction with the aliphatic nucleophile occurs through a backside SN2@P pathway while the reaction with the aromatic nucleophile proceeds through a novel SN2@Cl mechanism, followed by a frontside SN2@C mechanism. To the best of our knowledge, this is the first time that a SN2@Cl mechanism is reported. We also found that on reducing the bulkiness of substituents around the phosphorus atom, the backside SN2@P mechanism is preferred. The conclusions made from investigating the steric effect should help experimentalists to decide for the organophosphorus reactant to achieve the products of desired stereochemistry.

The synthesis and characterization of a range of bis(iminophosphoranyl)phosphide (BIPP) group 4 and coinage metals complexes is reported. BIPP ligands bind group 4 metals in a pseudo fac-fashion, and the central phosphorus atom enables the formation of d0–d10 heterobimetallic complexes. Various DFT computational tools (including AIM, ELF and NCI) show that the phosphorus–metal interaction is either electrostatic (Ti) or dative (Au, Cu). A bridged homobimetallic Cu–Cu complex was also prepared and its spectroscopic properties were investigated. The theoretical analysis of the P–P bond in BIPP complexes reveals that (i) BIPP are closely related to ambiphilic triphosphenium (TP) cations; (ii) the P–P bonds are normal covalent (i.e. not dative) in both BIPP and TP., The synthesis, characterization and computational analysis of a range of bis(iminophosphoranyl)phosphide (BIPP) group 4 and coinage metals complexes is reported. White phosphorus was used to install the central phosphorus atom.

Density functional calculations have been carried out to investigate the protonation pathways of phosphatranes, also known as Verkade bases, as a function of different equatorial substituents. The most favorable site of protonation is found to be at the phosphorus atom rather than the equatorial atom. The strength of transannular P⋯Nax interaction is responsible for the higher proton affinity of these bases. The proton transfer pathway from the phosphorus atom to the equatorial atom is kinetically very difficult owing to a high activation barrier. The initial deprotonation from the equatorial nitrogen atom is also favored by the presence of transannular interaction. The computed stabilization energies are found to depend largely on the phosphorus–equatorial bond strengths.

Conformational analysis of tris(3-methylphenyl)phosphine and its chalcogenides has been performed by methods of dipole moments, IR spectroscopy, and quantum chemistry [DFT B3PW91/6-31G(df,p)]. In solution, these compounds exist as an equilibrium of conformers with gauche- and cis-arrangement of the substituents at the phosphorus atom relative to the P=X bond (X = lone electron pair, O, S, Se).

The first example of 16-membered aminomethylphosphines with pyridyl substituents on the phosphorus atom was synthesized as an RSSR isomer by covalent self-assembly in the system 1,3-bis[(pyridin-2-yl)phosphino]propane–formaldehyde–isopropylamine.

A mild and effective method for the synthesis of new tetraarylphosphonium zwitterions and salts containing methoxy and hydroxy groups in aryl substituents at the phosphorus atom was developed. The structure of phosphorus-containing betaines and phosphonium salts was obtained by NMR spectroscopy.

Different pentacoordinate spirophosphoranes were investigated by H/D exchange and NMR tracking experiments. The H/D exchanged site of spirophosphoranes was confirmed to be the N H bond instead of the P H bond according to the integration of the signal changes in proton-decoupled, proton-coupled 31P NMR and 1H NMR tracking experiments. The reactivity of N H bond at the spiroring of spirophosphoranes was explored by the rate constant of H/D exchange of different spirophosphoranes. The results demonstrated that the reactivity of N H bond of spirophosphoranes was influenced by steric hindrance and the species of substituent at phosphorus atom, and the electronic effect of the substituent was the main effect factor on the reactivity of the N H bond. The strong electron-withdrawing group at phosphorus resulted in more reactive N H bond of spirophosphoranes. These results are beneficial to further understand and explore the characteristics of pentacoordinate spirophosphoranes.

The structure and ion-selective properties of some 2-phosphorylphenols were studied. It was shown that, irrespective of the nature of the substituents on the benzene ring and on the phosphorus atom, these compounds exhibit potentiometric selectivity to cesium cation. The crystal structures of 2-(diphenylphosphoryl)-4-ethylphenol and 2-[(diphenylphosphoryl)methyl]phenol were established.

Phosphorus Analogs of TSAO bearing an oxaphospholene ring instead of an oxathiole dioxide ring at C-3′ position were prepared. Strategy developed previously on saccharidic moiety was used with introduction of an electron withdrawing α group neighboring the phosphorus atom. Biological evaluation on both HIV-1 and HCV showed that these compounds have no activity.

4-[(2-Diphenylphosphanylphenyl)methyleneamino]benzoic acid (HL) is obtained by the condensation of o-diphenylphosphinobenzaldehyde and p-aminobenzoic acid. The reaction of AgNO3 and HL affords complex [Ag2L2] · H2O (I). The structure of complex I is determined by X-ray structure analysis (CIF file CCDC 1575064), and its reflectance and luminescence spectra are studied. Binuclear complex I is a cyclic molecule in which each of two silver(I) atoms coordinates one phosphorus atom and one oxygen atom of two bridging anions L. Compound I is characterized by emission in a range of 430–740 nm at λexc = 340 and 395 nm.

2-(5-Methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-4H-benzo[e]-1,3,2-dioxaphosphorin-4-one reacts with perfluorodiacetyl, 3,6-di(tert-butyl)-1,2-benzoquinone and phenanthrenequinone only with the participation of a three-coordinated phosphorus atom to form spirophosphoranes containing acyclic 5-methyl-2- phenyl-2H-1,2,3-diazaphosphol-4-yl substituent, whereas the interaction with tetrachloro-1,2-benzoquinone proceeds via expanding the six-membered heterocycle to the nine-membered one to form 2-(2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-2,9-dioxo-4,5,6,7-tetrachlorodibenzo[d,h]-1,3,8-trioxaphosphonine.

Organophosphorus compounds with a phosphorus atom attached to a phenyl group and two organothio/organoseleno groups were synthesized using the rhodium-catalyzed insertion reaction of the PhP group of pentaphenylcyclopentaphosphine (PhP)5 with acyclic disulfides and diselenides. The method was applied to the synthesis of heterocyclic compounds containing the S–P–S group by the reaction of (PhP)5 and cyclic disulfides such as 1,2-dithietes, 1,2-dithiocane, 1,4,5-dithiopane, and 1,2-dithiolanes.

The effect of Buchwald-type ligands on the platinum catalyzed hydrosilylation of vinyl-terminated polydimethylsiloxane has been studied by differential scanning calorimetry of platinum catalyst-containing silicone compositions. Dialkyl(biphenyl-2-yl)phosphines bearing bulky substituents at phosphorus atom are efficient inhibitors of the catalytic hydrosilylation process allowing one to increase the pot-life of silicone composition and to prevent the decomposition of the Pt-based catalyst.

A novel adsorption-based method for quantitative estimation of the phosphorus atom replacement for a (Si, H+) pair in the SAPO-11 framework is suggested. The most probable configurations and regularities in the location of silicon atoms and protons in the SAPO-11 structure containing 1, 2, 3 and 5 Si atoms per unit cell were determined by computations. A new force field for adsorption simulation in the H2 – SAPO system was developed. The dependence of averaged Henry's constants for H2 adsorption at 77 K on the amount of substituted Si was calculated. The effect of model used for computation of the Si distribution probability in the SAPO-11 on the adsorption properties in the H2 – SAPO system was studied. Practical applications of the method for several SAPO-11 frameworks with different Si concentrations are demonstrated.

Hexachlorocyclotriphosphazene is a ring compound consisting of an alternating phosphorus and nitrogen atom with two chlorine substituents attached to the phosphorus atom. The six chlorine atoms attached to this cyclo compound can be substituted with any different nucleophile that leads to changes in different chemical and physical properties. The major topics that were investigated in this research are the flame retardancy and dielectric properties of cyclotriphosphazene compounds. Cyclotriphosphazene compounds have high potential to act as a flame retardant, and this compound consists of two active elements attributed to its high flame-retardant character. This compound also demonstrated good ability as a flame retardant due to its low toxicity and less smoke produced. In addition, cyclotriphosphazene compounds were also investigated for their dielectric properties. Cyclotriphosphazene has high potential in the electrical field since it has dielectric properties that can be widely studied in the investigation of any potential application. This review presented literature studies focused on recent research development and studies in the field of cyclotriphosphazene that focused on synthesis, structural, flame retardancy, and dielectric properties of hexachlorocyclotriphosphazene compounds.

International audience; Proazaphosphatranes, also known as Verkade's superbases, have been investigated as ligands for gold(I). If the coordination to the gold center by the phosphorus atom suggests phosphine‐like behavior, gold(I)‐containing Verkade's superbase complexes could also be prepared from the weak conjugate acid azaphosphatrane by the formation of the corresponding silver complex and subsequent transmetalation to gold, similarly to the synthetic route used for complexes bearing N‐heterocyclic carbene ligands (NHCs). A competitive transmetalation experiment highlighted the higher lability of Verkade's superbases compared with NHCs. Furthermore, combined theoretical and experimental studies showed that they display strong σ‐donor ability, better than phosphines and similar to NHCs. Thus, some specific properties of both NHCs and phosphines are combined in Verkade's superbases, thereby providing a new approach to tuning the ligand properties of gold(I) complexes.