Phosphonate Moiety Research Articles

Synthesis and Herbicidal Activity of Novel Pyrimidinyl Derivatives Containing an α-Amino Phosphonate Moiety

In order to find novel pyrimidinyl carboxylic acid analogs with high activity and low toxicity, a series of novel pyrimidinyl derivatives containing an α-amino phosphonate moiety 5 was synthesized by the condensation of 4-(4,6-dimethoxypyrimidin-2-yloxy)phenoxyacetic 3a or propionic acids 3b with dialkyl α-amino substitutedbenzyl phosphonates 4. Their structures were characterized by spectroscopic data (IR, 1H NMR, 31P NMR, MS) and elemental analyses. The results of preliminary herbicidal activities (in vitro) showed that most of these compounds exhibited higher herbicidal activities against dicotyledonous weeds (Brassica campestris L) than monocotyledonous weeds (Echinochloa crus-galli). Further bioassays (in vivo) indicated that some of compounds 5 possessed selective herbicidal activity against amaranth pigweed (A. retroflexus) in post-emergence treatment. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Charge Transport across Phosphonate Monolayers on Indium Tin Oxide

Transition voltage spectroscopy was used to measure the charge injection properties of monolayers of bithiophene phosphonate, quarterthiophene phosphonate, and decylphosphonate covalently bonded to an indium tin oxide surface. Hysteresis was observed for all three phosphonates, which is possibly explained by charge retention at the phosphonate−ITO interface. Unlike previous work on thiolate-based molecular junctions, there is no significant difference between the charge injection barriers of the three phosphonates, suggesting that the phosphonate moiety dominates the observed charge injection properties.

Palladium-Catalyzed Propargylic Substitution with Phosphorus Nucleophiles: Efficient, Stereoselective Synthesis of Allenylphosphonates and Related Compounds

A new, efficient method is developed, based on a palladium(0)-catalyzed reaction of propargylic derivatives with various phosphorus nucleophiles, to produce allenylphosphonates and their analogues with defined stereochemistry in the allenic and the phosphonate moiety.

Glyphosate adsorption on montmorillonite: An experimental and theoretical study of surface complexes

In this study we perform X-ray diffraction and XPS analysis to study the adsorption of the herbicide glyphosate on montmorillonite. Structures of the surface complexes are proposed based on the XPS and XRD patterns and explored using molecular modeling techniques. Adsorption isotherms showed multistep profiles at all pHs studied, indicating the adsorption on aluminol and/or silanol groups of the external surface and in the interlayer space. PMG intercalation was indicated by the XRD patterns. The increase of the basal spacing as a function of the number of water molecules in the calculations indicated the appropriateness of the theoretical model to simulate macroscopic behaviors of the water/clay mineral interactions. Final conformations of the system determined by molecular mechanics indicated that the charged amino moiety was attracted by the negative surfaces of the interlayer space in absence or presence of water molecules, with marked pH dependence. Negative values of the estimated adsorption energies at all pH values studied suggested that glyphosate molecules were adsorbed via the amino moiety or through monodentate or bidentate complexes formed between the phosphonate moiety and the internal surfaces of the clay mineral, explaining the basal spacing changes at high concentrations of PMG.

Synthesis and Antiviral Bioactivity of Chiral Thioureas Containing Leucine and Phosphonate Moieties

A series of novel chiral thioureas 3a-n bearing leucine and phosphonate moieties were synthesized in excellent yields. The structures of the compounds were completely characterized by elemental analysis, IR, 1H-, 13C-, 31P- and 19F-NMR spectral data. A half-leaf method was used to determine the in vivo protective and curative efficacies of the title products against tobacco mosaic virus (TMV). The compounds 3l and 3n displayed good in vivo protection and curative effects against TMV with inhibitory rates of 60.1, 62.8% (protection) and 56.7, 53.6% (curative) at 0.5 mg/mL, respectively. To the best of our knowledge, this is the first report on the antiviral activity of chiral thioureas containing leucine and phosphonate moieties.

Functional identification and structure determination of two novel prolidases from cog1228 in the amidohydrolase superfamily .

Two uncharacterized enzymes from the amidohydrolase superfamily belonging to cog1228 were cloned, expressed, and purified to homogeneity. The two proteins, Sgx9260c ( gi|44242006 ) and Sgx9260b ( gi|44479596 ), were derived from environmental DNA samples originating from the Sargasso Sea. The catalytic function and substrate profiles for Sgx9260c and Sgx9260b were determined using a comprehensive library of dipeptides and N-acyl derivative of l-amino acids. Sgx9260c catalyzes the hydrolysis of Gly-l-Pro, l-Ala-l-Pro, and N-acyl derivatives of l-Pro. The best substrate identified to date is N-acetyl-l-Pro with a value of k(cat)/K(m) of 3 x 10(5) M(-1) s(-1). Sgx9260b catalyzes the hydrolysis of l-hydrophobic l-Pro dipeptides and N-acyl derivatives of l-Pro. The best substrate identified to date is N-propionyl-l-Pro with a value of k(cat)/K(m) of 1 x 10(5) M(-1) s(-1). Three-dimensional structures of both proteins were determined by X-ray diffraction methods (PDB codes 3MKV and 3FEQ ). These proteins fold as distorted (beta/alpha)(8)-barrels with two divalent cations in the active site. The structure of Sgx9260c was also determined as a complex with the N-methylphosphonate derivative of l-Pro (PDB code 3N2C ). In this structure the phosphonate moiety bridges the binuclear metal center, and one oxygen atom interacts with His-140. The alpha-carboxylate of the inhibitor interacts with Tyr-231. The proline side chain occupies a small substrate binding cavity formed by residues contributed from the loop that follows beta-strand 7 within the (beta/alpha)(8)-barrel. A total of 38 other proteins from cog1228 are predicted to have the same substrate profile based on conservation of the substrate binding residues. The structure of an evolutionarily related protein, Cc2672 from Caulobacter crecentus, was determined as a complex with the N-methylphosphonate derivative of l-arginine (PDB code 3MTW ).

Thiol−Ene Induced Diphosphonic Acid Functionalization of Superparamagnetic Iron Oxide Nanoparticles

Multifunctional organic molecules represent an interesting challenge for nanoparticle functionalization due to the potential for undesirable interactions between the substrate material and the variable functionalities, making it difficult to control the final orientation of the ligand. In the present study, UV-induced thiol-ene click chemistry has been utilized as a means of directed functionalization of bifunctional ligands on an iron oxide nanoparticle surface. Allyl diphosphonic acid ligand was covalently deposited on the surface of thiol-presenting iron oxide nanoparticles via the formation of a UV-induced thioether. This method of thiol-ene click chemistry offers a set of reaction conditions capable of controlling the ligand deposition and circumventing the natural affinity exhibited by the phosphonic acid moiety for the iron oxide surface. These claims are supported via a multimodal characterization platform which includes thermogravimetric analysis, X-ray photoelectron spectroscopy, and metal contact analysis and are consistent with a properly oriented, highly active ligand on the nanoparticle surface. These experiments suggest thiol-ene click chemistry as both a practical and generally applicable strategy for the directed deposition of multifunctional ligands on metal oxide nanoparticle surfaces.

Photopolymerization of Self-Assembled Monolayers of Diacetylenic Alkylphosphonic Acids on Group-III Nitride Substrates

This paper describes the fabrication and characterization of photopolymerizable alkylphosphonate self-assembled monolayers (SAMs) on group-III nitride substrates including GaN and Al(x)Ga(1-x)N (AlGaN; x = 0.2 and 0.25). Contact angle goniometry, visible absorption spectroscopy, and atomic force microscopy were used to assess the formation, desorption, and photopolymerization of SAMs of diacetylenic alkylphosphonic acids (CH(3)(CH(2))(n)-C[triple bond]C-C[triple bond]C-(CH(2))(m)PO(OH)(2); (m, n) = (3, 11), (6, 8), and (9, 5)). As with GaN substrates (Ito, T.; Forman, S. M.; Cao, C.; Li, F.; Eddy, C. R., Jr.; Mastro, M. A.; Holm, R. T.; Henry, R. L.; Hohn, K.; Edgar, J. H. Langmuir 2008, 24, 6630-6635), alkylphosphonic acids formed SAMs on UV/O(3)-treated AlGaN substrates from their toluene solutions in contrast to other primary substituted hydrocarbons with a terminal -COOH, -NH(2), -OH, or -SH group. Diacetylenic alkylphosphonate SAMs on group-III nitrides could be polymerized by UV irradiation (254 nm), as indicated by the appearance of a visible absorption band around 640 nm and also by their significantly reduced desorption from the surface in a 0.1 M aqueous NaOH solution. A longer UV irradiation time was required to maximize the photopolymerization of a SAM having a diacetylene group close to the terminal phosphonate moiety, probably because of the hindrance of the topochemical polymerization due to the limited flexibility of the cross-linking moieties on an atomically rough substrate surface.

Phosphonated fully aromatic polyethers for PEMFCs applications

AbstractNew homopolymers and copolymers based on aromatic polyethers bearing side diphosphonate and diphosphonic groups have been synthesized. These synthetic efforts resulted in homo and copolymers of high thermal stability but moderate molecular weights. To evaluate the influence of the immobilized phosphonate ester and phosphonic acid moieties on polymer electrolyte membranes for fuel cells applications, blends of the newly synthesized homo and copolymers with a pyridine‐based aromatic polyether were prepared. These blends were miscible with high glass transition temperatures and high thermal stabilities. Furthermore, the introduction of these groups to a polymeric backbone significantly increases the doping ability in phosphoric acid compared to the net matrix as well as the ionic conductivity for high doping levels. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2817–2827, 2010

New Fluorinated Polymers Bearing Pendant Phosphonic Acid Groups. Proton Conducting Membranes for Fuel Cell

The synthesis and characterizations of original fluorinated copolymers bearing phosphonic acid side functions for novel membranes potentially involved in fuel cell applications are presented. These copolymers were obtained by chemical modifications of various poly(CTFE-alt-IEVE) and poly[(CTFE-alt-IEVE)-co-(CTFE-EVE)] terpolymers (where CTFE, IEVE, and EVE stand for chlorotrifluoroethylene, 2-iodoethyl vinyl ether, and ethyl vinyl ether) via the Arbuzov reaction. Then, the hydrolysis of the phosphonate moieties into phosphonic acid groups was carried out quantitatively in mild conditions, in the presence of bromotrimethylsilane. The ionic exchange capacities (IECs) determined by potentiometric titration were ranging from 2.9 to 6.8 mequiv/g. The thermal and electrochemical properties of the resulting membranes (processed by casting) were investigated. Whatever the phosphonic acid content, the main degradation started from 250 °C, showing a high thermo-oxidative stability of these copolymers. At 25 °C and ...

Layered Calcium Structures ofp-Phosphonic AcidO-Methyl-Calix[6]arene

Hexamethoxy-calix[6]arene has been fully functionalized with p-phosphonic acid groups on the upper rim in 57% yield over three steps, and has been authenticated in the solid state by X-ray diffraction as either a nitrate salt or one of two calcium complexes. The latter differ by the ratio of calcium ions per calixarene, either 3:1 or 4:1. In both structures the coordination sphere of the calcium ions is made up of oxygen atoms from the phosphonic acid groups and from water of crystallization, as part of extended polymeric layers in the extended 3D packing. Hirshfeld surface analysis shows extensive O...H and O...Ca interactions for the phosphonic acid moieties in both calcium structures. MALDI-TOF MS of the hexaphosphonic acid shows nano-arrays consisting of up to a maximum of 28 calixarene units.

Comparison of Thorium(IV) and Uranium(VI) Carboxyphosphonates

The hydrothermal reactions of thorium nitrate and uranyl acetate with carboxyphenylphosphonic acid and HF result in the formation of ThF(2)(PO(3)C(6)H(4)CO(2)H) and UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O, respectively. ThF(2)(PO(3)C(6)H(4)CO(2)H) adopts a pillared structure constructed from thorium oxyfluoride layers built from [ThO(4)F(4)] units that are bridged by carboxyphenylphosphonate to yield a three-dimensional network. UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O forms one-dimensional chains of UO(6) tetragonal bipyramids that are bridged by the phosphonate moiety of the ligand. The carboxylate portion of the structure links the chains together into layers via a hydrogen-bonding network. The higher effective charge and more isotropic coordination of the Th(IV) centers versus the uranium centers contained within uranyl cations allow for coordination by the protonated carboxylate portions of the ligands to the thorium cations, which does not occur with uranium in carboxyphosphonates. UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O displays vibronically coupled fluorescence and the potential for energy transfer from the ligand to the charge-transfer bands of the uranyl cations. The main fluorescence by the ligand is quenched in ThF(2)(PO(3)C(6)H(4)CO(2)H).

Aminophosphonic Acids and Derivatives. Synthesis and Biological Applications

In recent years, phosphonic acids and their derivatives have received increasing attention as analogues of a series of naturally occurring phosphates and as "bio-isosteric phosphorus analogues" of amino acids. Unlike a phosphate group, the phosphonate moiety is not readily hydrolyzed, in a biological environment, by the enzymes involved in the phosphate cleavage. This feature makes these compounds extremely useful in several applications, in metabolic regulation, in enhancement or inhibition studies, in the development of potential drugs against several metabolic disorders. The great potential of these compounds in biological applications resulted in an intense effort directed to the development of efficient synthetic methods for their preparation, with particular attention to stereoselective synthesis. The purpose of this review is to give an up-to-date account of the chemistry, the synthesis and the biological activity of aminophosphonic acids and their derivatives.

One, two, and three methylene phosphonic acid groups (–CH2PO3H2) on a mesitylene ring: synthesis, characterization and aspects of supramolecular aggregation

The ease of substitution of –CH2Br group on the mesitylene ring in a stepwise manner has been exploited to prepare mesitylene mono-, bis-, and tris-methylene phosphonic acids C6H2Me3(CH2PO3H2) (1), C6HMe3(CH2PO3H2)2 (2), and C6Me3(CH2PO3H2)3 (3) in 80–90% yield, through a Michaelis–Arbuzov reaction followed by acid hydrolysis. Compounds 1–4 have been characterized by analytical and spectroscopic (IR, NMR, and MS) techniques. The X-ray structural investigations on all the three compounds reveal that the central mesitylene ring is a robust platform for hosting multiple methylene phosphonic acid groups. Mesitylene mono-methylene phosphonic acid 1, which can be considered as the sterically encumbered modification of benzyl phosphonic acid, interestingly associates as a one-dimensional tubular structure through extensive O–H⋯O hydrogen bonding between adjacent –PO3H2 groups, albeit with no such interactions between the tubes due to the highly hydrophobic nature of the surface. The X-ray structure of mesitylene-1,3-diphosphonic acid 2 reveals that the molecules exhibit a syn-orientation of the –CH2PO3H2, which are involved in extensive P–OH⋯O hydrogen bonding to result in a two-dimensional layered structure. The presence of three –PO3H2 units on the same side of the mesitylene ring in 3 results in a three-dimensional framework solid. The present studies clearly reveal a linear relationship between the dimensionality of the supramolecular structure and the number of phosphonic acid moieties on the mesitylene ring.

Theoretical study of the surface modification of indium tin oxide with trifluorophenyl phosphonic acid molecules: impact of coverage density and binding geometry

The interface composed of 3,4,5-trifluorophenyl phosphonic acid (PA) molecules chemisorbed on the indium-tin oxide (ITO) surface was studied at the density functional theory level. The impact of coverage density and binding geometry of the PA molecules on the ITO surface characteristics has been investigated systematically by increasing the PA surface coverage density from one to four PA molecules per surface unit cell. The calculations point to several bonding schemes where the phosphonate (PO3) moieties are directly bonded to the surface In/Sn atoms and/or form hydrogen bonds with the hydroxyl groups present on the ITO surface. Both PA coverage density and binding geometry strongly influence the work-function modifications of the ITO surface upon chemisorption. The oxygen core-level binding energy shifts have been calculated and compare favorably with the experimental X-ray photoelectron spectroscopy data. Substantial depolarization effects are observed within the PA monolayer at high coverage densities.

Structure–activity relationships of the phosphonate antibiotic dehydrophos

Synthetic derivatives of the phosphonate antibiotic dehydrophos were tested for antimicrobial activity. Both the phosphonate monomethyl ester and the vinyl phosphonate moiety proved to be important for bacteriocidal activity of the natural product.

Novel double-chained or double-layered metal diphosphonates: synergic coordination effect of two closely linked phosphonate moieties promoted by large metal ionic radius

Hydrothermal reactions of PbII or BaII ion with N,N-dimethylaminomethane-1,1-diphosphonic acid (H4L) afforded a double-chained lead(II) diphosphonate and a double-layered barium(II) diphosphonate, namely, [Pb(H2L)] (1) and [Ba2(H2L)2] (2). The two closely linked phosphonate moieties in the diphosphonate ligand exhibit a highly synergic coordination effect, which is mainly promoted by the large ionic radius of the PbII or BaII ion. More interestingly, the unusual double-layer structure in 2 contains cubane-like Ba8 cages and each cage is face-shared with four adjacent ones.

Synthesis and characterization of high refractive index nanoparticle/poly(arylene ether ketone) nanocomposites

This paper presents a successful synthesis of transparent organic–inorganic nanocomposites from poly(arylene ether ketone) (PAEK)-based matrix polymer and BaTiO3 nanoparticles. The dispersibility of nanoparticles was significantly improved by both the introduction of phosphonic acid moiety into the polymer chain and the organic modification of the nanoparticle surface. The structure of phosphonic-acid-modified PAEK polymer was studied by gel permeation chromatography, 31P nuclear magnetic resonance spectroscopy and X-ray fluorescence spectroscopy. Thermal properties of nanocomposites were studied by thermogravimetry and differential scanning calorimetry. Optical clarity of nanocomposites was evaluated by a hazemeter and regular transmittance spectroscopy. Dispersion of nanoparticles was also demonstrated by transmission electron microscopic observation. Fourier transform infrared analysis was carried out to investigate the interaction between the polymer matrix and nanoparticles. Refractive indices of the obtained transparent nanocomposites, which contain up to 44.1 wt% of nanoparticles, were measured. A high refractive index of 1.72 at 589 nm was achieved.

Synthesis of (sulfonyl)methylphosphonate analogs of prenyl diphosphates

Syntheses of several (sulfonyl)methylphosphonate analogs of geranyl, neryl, and farnesyl diphosphates are described. Key steps include utilization of an ( E)-selective Horner–Wadsworth–Emmons olefination which couples an aldehyde to the sulfone phosphonate moiety, and a selective reduction of the resulting dienyl sulfone phosphonate substrates.

Tetraarylphosphonium Salts as Soluble Supports for Oxidative Catalysts and Reagents

Tetraarylphosphonium (TAP)-supported DMSO, TEMPO, and DIB reagents were synthesized and used for the oxidation of alcohols, including Swern oxidation and for the alpha-acetoxylation of ketones. By taking advantage of the predictable solubility properties of the TAP unit, simple precipitation and filtration of the phosphonium moiety permit complete separation of the desired oxidation products. This paper describes the preparation of these three TAP-supported oxidative reagents and their activity in the aforementioned oxidative transformations. Furthermore, we have demonstrated that these reagents can be recycled directly when used in catalytic processes and following regeneration when used in stoichiometric processes.