Butylphosphonic Acid Research Articles

Thermal Stability and Orthogonal Functionalization of Organophosphonate Self-Assembled Monolayers as Potential Liners for Cu Interconnect.

In this study, we investigated the thermal stabilities of butylphosphonic acid (BPA) and aminopropyltriethoxysilane (APTES) self-assembled monolayers (SAM) on a Si substrate. The thermal desorption and the thermal cleavage of the BPA and APTES SAM film on the Si substrate were studied by X-ray photoelectron spectroscopy (XPS) upon thermal treatment from 50 to 550 °C. XPS analyses show that the onset of the thermal desorption of the APTES monolayer occurs at 250 °C and the APTES SAM completely decomposed at 400 °C. Conversely, BPA SAM on Si shows that the onset of thermal desorption occurs at 350 °C, and the BPA SAM completely desorbed at approximately 500 °C. Our study revealed that the organophosphonate SAM is a more stable SAM in modifying the dielectric sidewalls of a Cu interconnect when compared to organosilane SAM. To overcome the spontaneous reaction of the organophosphonate film on the metal substrate, a simple orthogonal functionalization method using thiolate SAM as a sacrificial layer was also demonstrated in this study.

Utilization of phosphonic acid compounds by marine bacteria of the genera Phaeobacter, Ruegeria, and Thalassospira (α-Proteobacteria).

Phosphonic acid (phosphonate) that possesses a carbon-phosphours bond is a chemically stable form of organic phosphorus. Various phosphonic acids are widely distributed in oceanic waters; in particular, methylphosphonic acid (namely methylphosphonate) is believed to be responsible for global methane production. To discuss the microbial degradation of phosphonic acids, we investigated the utilization of phosphonic acid compounds by cultures of marine bacteria, Phaeobacter sp., Ruegeria sp. (Rhodobacterales), and Thalassospira sp. (Rhodospirillales). These bacterial cultures were able to grow on methylphosphonic acid as well as on the tested alkyl-, carboxy-, aminoalkyl-, and hydroxyalkyl-phosphonic acid compounds. Cell yields and growth rates of Ruegeria and Thalassospira cultures grown on methyl-, ethyl-, propyl-, and butyl-phosphonic acid compounds tended to decrease with increasing alkyl chain length. In contrast, Phaeobacter sp. grew well on such alkyl-phosphonic acids. Our results suggest that these marine bacteria, which exhibit varied utilization, are involved in microbial degradation of various phosphonic acid compounds.

Modulating MnO2 Interface with Flexible and Self-Adhering Alkylphosphonic Layers for High-Performance Zn-MnO2 Batteries.

Metal oxides are essential electrode materials for high-energy-density batteries, but it remains highly challenging to modulate their interfacial charge-transfer process and improve their cycling stability. Here, using MnO2 nanofibers as an example, we describe the application of self-assembled alkylphosphonic modification layers for significantly improved cycling stability and high-rate performance of Zn-MnO2 batteries. Two modifier organic molecules with the same phosphonic functional group but different alkyl tail lengths were employed and systematically compared, including butylphosphonic acid (BPA) and decylphosphonic acid (DPA). The phosphonic groups form strong interfacial covalent bonding and assist the generation of conformal and flexible coatings with few nanometers thickness on a MnO2 surface. The intertwined alkylphosphonic molecules in the modulation layers have interconnected phosphonic groups, which improve interfacial charge transfer of H+ ions for fast conversion of MnO2 to MnOOH without compromising electrolyte wetting. Importantly, the coating layers effectively reduce dissolutive loss of Mn2+ from MnO2 during battery cycling since diffusion of both water molecules and divalent Mn2+ cations was inhibited across the modification layers. The flexible coatings could readily adapt to the morphological changes of MnO2 during battery cycling and provide long-lasting protection. Overall, we identified that BPA has the optimal balance of hydrophobic-hydrophilic components and enabled modified MnO2 cathodes with >30% improved discharge capacity compared with unmodified MnO2 cathodes, together with substantially improved long-term cycling stability with >60% capacity retention for 400 cycles in aqueous ZnSO4 electrolytes without any Mn2+ additive. This work provides new insights into tuning electrochemical pathways that move away from the prevailing rigid, ceramic coating-based surface modifications.

Antibacterial activity, GC-MS and TLC/HPTLC Fingerprint analysis of Plectranthus vettiveroides (Jacob) N.P. Singh and B.D. Sharma -An endemic plant in South India

The study focused to evaluate antibacterial activity of various parts of Plectranthus vettiveroides, GC-MS analysis and HPTLC fingerprint profile was done for chloroform leaf extract of Plectranthus vettiveroides. Different parts of Plectranthus vettiveroides successively extracted with n-hexane, chloroform, ethyl acetate and ethanol. All these extracts were performed for antibacterial activity against Staphylococcus epidermidis, Shigella flexneri, Enterococcus faecalis, Vibrio parahaemolyticus, Micrococcus luteus, Yersinia enterocolitica and Salmonella typhimurium by disc diffusion method. The leaves chloroform extract was first time reported prominent antibacterial activity and minimum inhibitory concentration calculated against Staphylococcus epidermidis, Shigella flexneri, Enterococcus faecalis, Vibrio parahaemolyticus and Micrococcus luteus. The chemical composition of the chloroform leaves extract was analysed by GC–MS and HPTLC fingerprint profile was done. The major chemical constituents are butylphosphonic acid, pentyl 4-(2-phenylprop-2-yl) phenyl ester, benzaldehyde, 3-nitro-(2, 4-dinitrophenyl) hydrazine and γ-sitosterol. These major compounds might have contributed for the antibacterial activity of chloroform extract could be a potential source for controlling human bacterial disease.

Hydrothermal treatment and butylphosphonic acid derived self-assembled monolayers for improving the surface chemistry and corrosion resistance of AZ61 magnesium alloy

The hydrothermal treatment followed by a self-assembled monolayer (SAM) of 1-butylphosphonic acid through the tethering by aggregation and growth (T-BAG) method was employed to produce protective surface coatings on the Mg-6Al-1Zn alloy (AZ61) for reducing the degradation rate in physiological environments. Potentiodynamic polarization measurements revealed that the organic self-assembled monolayer and Mg(OH)2 coating can further enhance the surface chemical stability and corrosion resistance of Mg alloys. SAM-treated Mg(OH)2 coatings can be served as a more passive surface layer as a result of their much higher charge transfer resistance and the presence of Warburg impedance in electrochemical impedance spectroscopy measurement.

Adsorption kinetics of phosphonic acids and proteins on functionalized Indium tin oxide surfaces using electrochemical impedance spectroscopy

Phosphonic acids (PAs) are known to have a spontaneous affinity for chemisorption onto several metal oxide surfaces. The self – assembled monolayer (SAM) of phosphonates provides a platform for further surface modifications using biomolecules that can be adopted for the development of sensors and biosensors. With this in view, we studied adsorption kinetics of different phosphonic acids of short chain lengths such as phosphonopropionic acid (PPA), aminobenzylphosphonic acid (ABPA), benzylphosphonic acid (BPA), butylphosphonic acid (BuPA), and a long chain decylphosphonic acid (DecPA) on ITO surface using electrochemical impedance spectroscopy (EIS) at short and long time scales. The dependence of solution concentration on formation kinetics is studied and the existences of two discrete kinetics were revealed. We show from our studies that the rate of adsorption is controlled by diffusion at small time scales. Further, the phosphonic acid modified surface is also used as a substrate for the adsorption of cytochromeC (CytC) (a heme protein) and urease (an enzyme) and the kinetics of their adsorption has been studied.

Improved performance and stability of perovskite solar cells by crystal crosslinking with alkylphosphonic acid ω-ammonium chlorides.

In the past few years, organic-inorganic halide perovskites have rapidly emerged as promising materials for photovoltaic applications, but simultaneously achieving high performance and long-term stability has proved challenging. Here, we show a one-step solution-processing strategy using phosphonic acid ammonium additives that results in efficient perovskite solar cells with enhanced stability. We modify the surface of methylammonium lead triiodide (CH3NH3PbI3) perovskite by spin-coating its precursor solution in the presence of butylphosphonic acid 4-ammonium chloride. Morphological, structural and elemental analyses show that the phosphonic acid ammonium additive acts as a crosslink between neighbouring grains in the perovskite structure, through strong hydrogen bonding of the -PO(OH)2 and -NH3(+) terminal groups to the perovskite surface. The additives facilitate the incorporation of the perovskite within a mesoporous TiO2 scaffold, as well as the growth of a uniform perovskite layer at the surface, enhancing the material's photovoltaic performance from 8.8 to 16.7% as well as its resistance to moisture.

Influence of modification time and high frequency ultrasound irradiation on self-assembling of alkylphosphonic acids on stainless steel: Electrochemical and spectroscopic studies

Self-assembly of alkylphosphonic acids on stainless steel was investigated under different conditions. Four different alkylphosphonic acids exhibiting alkyl chain of various size were synthesized and studied: butylphosphonic acid (C4P), octylphosphonic acid (C8P), decylphosphonic acid (C10P), and hexadecylphosphonic acid (C16P). Electrochemistry experiments were extensively carried out in order to determine electrochemical surface blocking of adsorbed layers in function of grafting time. In term of surface blocking, an 8h modification time was optimal for all alkylphosphonic acids. Longer immersion times lead to degradation of adsorbed layers. For the first time, grafting of C16P was studied under high frequency ultrasound irradiation. Interestingly, grafting process is highly accelerated under sonication and well-covering C16P modified substrates are obtained after 1h of immersion under ultrasound irradiation. This would allow to elaborate high-quality alkylphosphonic acids modified samples within much shorter times. Water contact angles measurements and X-ray Photoelectrons Spectroscopy (XPS) confirmed presence of adsorbed alkylphosphonic acids on stainless steel surface. A very tight link between electrochemical blocking, surface hydrophobicity and species chemical grafting was established.

Selective, electrochemically activated biofunctionalization of In2O3 nanowires using an air-stable surface modifier.

Selective electrochemically activated biofunctionalization of In(2)O(3) nanowires (NWs) has been achieved, using monolayer coatings of p-dimethoxybenzene derivatives. Monolayer coatings of 4-(2,5-dimethoxyphenyl)butyl-phosphonic acid (DMP-PA) were deposited on planar indium-tin oxide (ITO) electrodes and In(2)O(3) NWs. The electrochemical behavior of the monolayer coating was first studied using ITO electrodes, as a model system for In(2)O(3) nanowires. When a potential of 950 mV vs a Ag/AgCl reference electrode is applied to an ITO electrode coated with DMP-PA in PBS buffer, the p-dimethoxyphenyl groups are converted to p-benzoquinone (BQ). The electrochemically formed benzoquinone groups react readily with alkyl thiol groups via a Michael addition. The reaction strategy optimized on ITO was applied to an In(2)O(3) NW mat sample coated with DMP-PA. Applying a potential of 950 mV to metal electrodes deposited on NWs converts the DMP-PA NW coating to BQ-PA, which reacts with a thiol-terminated 20-base oligonucleotide. These NWs showed strong fluorescence response after paring with the dye labeled compliment, demonstrating that the probe was bound to the NW surface and that it remained active toward hybridization with its compliment. The unactivated DMP-PA coated NWs showed no response, demonstrating the selective electrochemical functionalization of NWs and the potential of using them in multiplex sensing. We also compared the p-dimethoxybenzene derivative to the conventional hydroquinone analog. The results show that the former can largely enhance the selectivity during the functionalization of both ITO and In(2)O(3) NWs.

Synthesis and Characterization of a Family of Penta- and Tetra-Manganese(III) Complexes Derived from an Assembly System Containing tert-Butylphosphonic Acid

A family of manganese complexes, [Mn 5O 3( t-BuPO 3) 2(MeCOO) 5(H 2O)(phen) 2] ( 1), [Mn 5O 3( t-BuPO 3) 2(PhCOO) 5(phen) 2] ( 2), [Mn 4O 2( t-BuPO 3) 2(RCOO) 4(bpy) 2] (R = Me, ( 3); R = Ph, ( 4)), NBu (n) 4[Mn 4O 2(EtCOO) 3(MeCOO) 4(pic) 2] ( 5), NR' 4[Mn 4O 2( i-PrCOO) 7(pic) 2] (R' = Bu (n) , ( 6); R' = Et, ( 7)), were synthesized and characterized. The seven manganese clusters were all prepared from a reaction system containing tert-butylphosphonic acid, Mn(O 2CR) 2 (R = Me, Ph) and NR' 4MnO 4 (R' = Bu (n) , Et) with similar procedures except for using different N-containing ligands (1,10-phenanthroline (phen), 2,2'-bipyridine (bpy) and picolinic acid (picH)) as coligands. The structures of these complexes vary with the N-containing donors. Both the cores of complexes 1 and 2 feature three mu 3-O and two capping t-BuPO 3 (2-) groups bridging five Mn (III) atoms to form a basket-like cage structure. Complexes 3 and 4 both have one [Mn 4(mu 3-O) 2] (8+) core with four coplanar Mn (III) atoms disposed in an extended "butterfly-like" arrangement and two capping mu 3- t-BuPO 3 (2-) binding to three manganese centers above and below the Mn 4 plane. Complexes 5, 6, and 7 all possess one [Mn 4(mu 3-O) 2] (8+) core just as complexes 3 and 4, but they display a folded "butterfly-like" conformation with the four Mn (III) atoms nonplanar. Thus, the seven compounds are classified into three types, and three representative compounds 1.2H 2O.MeOH.MeCN , 3.6H 2O.2MeCOOH , and 5.0.5H 2O have been characterized by IR spectroscopy, ESI-MS spectroscopy, magnetic measurements and in situ UV-vis-NIR spectroelectrochemical analysis. Magnetic susceptibility measurements reveal the existence of both ferromagnetic and antiferromagnetic interactions between the adjacent Mn (III) ions in compound 1.2H 2O.MeOH.MeCN , and antiferromagnetic interactions in 3.6H 2O.2MeCOOH and 5.0.5H 2O. Fitting the experimental data led to the following parameters: J 1 = -2.18 cm (-1), J 2 = 6.93 cm (-1), J 3 = -13.94 cm (-1), J 4 = -9.62 cm (-1), J 5 = -11.17 cm (-1), g = 2.00 ( 1.2H 2O.MeOH.MeCN ), J 1 = -5.41 cm (-1), J 2 = -35.44 cm (-1), g = 2.13, zJ' = -1.55 cm (-1) ( 3.6H 2O.2MeCOOH ) and J 1 = -2.29 cm (-1), J 2 = -35.21 cm (-1), g = 2.02, zJ' = -0.86 cm (-1) ( 5.0.5H 2O ).

Chemical modification of iron oxide surface with organosilicon and organophosphorous compounds

The feasibility of modifying iron oxides (α-Fe2O3, γ-Fe2O3, and an oxide covering the surface of carbonyl iron) with various organosilicon and organophosphorous compounds has been studied. It has been shown that the surfaces of these oxides can be successfully modified with ethoxysilanes and diethyl ester of butylphosphonic acid. Resultant grafted layers have being found to be rather hydrolytically and thermally stable. The effect of the modification on the corrosion and erosion stability of carbonyl iron has been investigated. It has been demonstrated that the modifying layers can efficiently protect carbonyl iron particles from corrosion.

Selective Functionalization of In2O3 Nanowire Mat Devices for Biosensing Applications

A strategy to covalently attach biological molecules to the electrochemically active surface of indium oxide nanowire (In2O3 NW) mat devices is presented. A self-assembled monolayer (SAM) of 4-(1,4-dihydroxybenzene)butyl phosphonic acid (HQ-PA) was generated on an indium tin oxide (ITO)-coated glass and In2O3 NWs surface. The chemical steps required for surface derivatization were optimized on an ITO surface prior to modifying the In2O3 NWs. The hydroquinone group contained in the HQ-PA SAM was electrochemically oxidized to quinone (Q-PA) at +330 mV. The monolayer of Q-PA was allowed to react with a thiol-terminated DNA. The DNA was paired to its complementary strand tagged with a fluorescence dye. Attachment of DNA was verified using fluorescence microscopy. A device was subsequently prepared on a SiO2-supported mat of In2O3 NWs by depositing gold electrodes on the mat surface. The reaction strategy optimized on ITO was applied to this In2O3 NW-based device. Arrays of In2O3 NWs on a single substrate were electrochemically activated in a selective manner to Q-PA. Activated In2O3 NWs underwent reaction with HS-DNA and gave a positive fluorescence response after pairing with the dye-DNA. The unactivated In2O3 NWs gave no response, thus demonstrating selective functionalization of an In2O3 NW array. This can be considered a key step for the future fabrication of large-scale, inexpensive, nanoscale biosensors.

Tert-Butylphosphonic acid: from the bulk to the gas phase.

The structure of tert-butylphosphonic acid in the solid, in solution, and in the gas phase was studied by single-crystal X-ray diffraction, (1)H and (31)P NMR spectroscopic studies in solution, solid-state (31)P NMR spectroscopy, and electrospray ionization mass spectrometry. In addition, density functional theory (DFT) calculations at the B3LYP/6-31G*, B3LYP/6-31+G*, and B3LYP/6-311+G* level of theory for a large number of H-bonded aggregates of the type (tBuPO(3)H(2))(n) (C(n), P(n); n=1-7) support the experimental work. Crystallization of tBuPO(3)H(2) from polar solvents such as CH(3)CN or THF gives the H-bonded one-dimensional polymer 2, whereas crystallization from the less polar solvent CDCl(3) favors the formation of the H-bonded cluster (tBuPO(3)H(2))(6).CDCl(3) (1). In CDCl(3) the hexamer (tBuPO(3)H(2))(6) (C(6)) is replaced by smaller aggregates down to the monomer with decreasing concentration. DFT calculations and natural bond orbital (NBO) analyses for the clusters C(1)-C(7) and the linear arrays P(1)-P(7) reveal the hexamer C(6) to be the energetically favored structure resulting from cooperative strengthening of the hydrogen bonds in the H-bonded framework. However, the average hydrogen bond strengths calculated for C(6) and P(2) do not differ significantly (42-43 kJ mol(-1)). The average distances r(O.O), r(Obond;H), r(Pdbond;O), and r(Pbond;OH) in C(1)-C(7) and P(1)-P(7) are closely related to the hydrogen bond strength. Electrospray ionization mass spectrometry shows the presence of different anionic species of the type [(tBuPO(3)H(2))(n)-H](-) (A(1)-A(7), n=1-7) depending on the instrumental conditions. DFT calculations at the B3LYP/6-31G* level of theory were carried out for A(1)-A(6). We suggest the dimer [(tBuPO(3)H(2))(2)-H](-) (A(2)) and the trimer [(tBuPO(3)H(2))(3)-H](-) (A(3)) are the energetically favored anionic structures. A hydrogen bond energy of approximately 83 kJ mol(-1) was calculated for A(2). Electrospray ionization mass spectrometry is not suitable to study the assembling process of neutral H-bonded tert-butylphosphonic acid since the removal of a proton from the neutral aggregates has a large influence on the hydrogen bond strength and the cluster structure.

Organic/Inorganic Langmuir−Blodgett Films Based on Metal Phosphonates. 4. Thermal Stability1

The thermal stability of metal phosphonate Langmuir−Blodgett (LB) films formed from the amphiphiles octadecylphosphonic acid (OPA) and an azobenzene-derivatized phosphonic acid, (4-(4‘-tetradecyloxyphenyldiazenyl)phenyl)butylphosphonic acid (A4), with divalent and trivalent metal ions has been examined. These films are characterized by the formation of a metal phosphonate continuous lattice in the polar region of the transferred bilayers. The behavior of the films upon heating and with temperature cycling was studied with attenuated total reflectance (ATR)-FTIR, transmission FTIR, absorbance spectroscopy, and X-ray diffraction. A reversible transition is observed between 40 and 50 °C in each film, and this process is assigned as a premelting transition in analogy to similar transitions observed in previously studied LB films. Irreversible disordering of the organic networks is observed for each film at higher temperatures, occurring near 150 °C in the lanthanum octadecylphosphonate film, near 140 °C in the manganese octadecylphosphonate film, and near 120 °C in lanthanide films of A4. Despite disordering of the organic network, FTIR and X-ray diffraction indicate that the inorganic network remains intact to above 180 °C. The inorganic continuous lattice network is shown to greatly enhance the thermal stability of the metal phosphonate LB films relative to that of the traditional carboxylic acid-based films.

Organic/Inorganic Langmuir−Blodgett Films Based on Metal Phosphonates. 3. An Azobenzene-Derivatized Phosphonic Acid Forms Continuous Lattice Layers with Divalent, Trivalent, and Tetravalent Metal Ions1

Metal phosphonate Langmuir−Blodgett (LB) films of an azobenzene-functionalized phosphonic acid amphiphile, (4-(4‘-tetradecyloxyphenyldiazenyl)phenyl)butylphosphonic acid (A4), have been prepared with Zr4+, La3+, Gd3+, Ba2+, Mn2+, and Cd2+. Film formation and quality are characterized with optical spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The azobenzene chromophores are strongly H-aggregated in all of the metal phosphonate LB films. With divalent and trivalent ions, the in-plane metal phosphonate structure observed in the LB films is the same as that found in analogous solid-state layered phosphonates and depends on the identity of the metal ion. Films of A4 with the lanthanide ions La3+ and Gd3+ form with stoichiometry MH(O3PR)2. When Ba2+ is incorporated into the films, the M(HO3PR)2 structure-type is adopted, while Mn2+ and Cd2+ give rise to films of A4 with the stoichiometry M(O3PR)...

Organic/Inorganic Langmuir−Blodgett Films Based on Metal Phosphonates: Preparation and Characterization of Phenoxy- and Biphenoxy-Substituted Zirconium Phosphonate Films

Zirconium phosphonate Langmuir−Blodgett (LB) films have been prepared where phenoxy and biphenoxy functional groups are placed in the organic tail at different positions relative to the phosphonate headgroup. The organophosphonic acids 4-octadecyloxyphenylphosphonic acid (P0), 4-(4‘-tetradecyloxyphenyl)butylphosphonic acid (P4), 4‘-octadecyloxybiphenylphosphonic acid (B0), and 4-(4‘-tetradecyloxybiphenyl)butylphosphonic acid (B4) were synthesized for this study. Pressure vs area isotherms of Langmuir monolayers are well-behaved except in the case of B0, where aggregation results in a very rigid monolayer. Using a previously developed three-step deposition procedure, both alternating layer and symmetric bilayer zirconium phosphonate films have been prepared and characterized. A combination of XPS, X-ray diffraction, and ATR-FTIR analyses indicate that organized zirconium phosphonate LB layers are formed in each case. Polarized ATR-FTIR was used to determine the orientation of the different functional groups leading to models for the molecular orientation within the films. In cases where the phenoxy or biphenoxy groups are separated from the phosphonate headgroup, deuteration of the terminal alkyl chain allows for the resolution of the different alkyl segments. Differences in molecular orientations are observed depending on whether the monolayers are deposited on the downstroke (template layer) or on the upstroke (capping layer) of the three-step deposition procedure, and these differences are attributed to the strong zirconium−phosphonate bonding. Subtle orientational differences are also seen for the same capping layers deposited onto different templates. The results show that the zirconium phosphonate LB deposition method may be extended beyond simple alkylphosphonates to organic groups containing aromatic moieties.

Synthesis of phosphonate and ether analogs of rac-phosphatidyl-L-serine

The chemical synthesis of four phosphonate-containing phosphatidylserine analogs namely, L-serine (±)-[2,3-bis(hexadecyloxy) and 2,3-bis(Palmitoyloxy)-propyl] phosphonates, and L-serine (±)-[3,4-bis(hexadecyloxy and 3,4-bis(palmitoyloxy)-butyl]phosphonates is described. (±)-2,3-Bis(hexadecyloxy) and 2,3-bis(palmitoyloxy)-propylphosphonic acids and (±)-3,4-bis (hexadecyloxy)butylphosphonic acid were prepared by reaction of tris(trimethylsilyl) phosphite on the corresponding haloalkane. Condensation of the above phosphonic acids or (±)-3,4-bis (palmitoyloxy)butylphosphonic acid with N-carboxy-L-serine dibenzyl ester in the presence of trichloroacetonitrile or triisopropylbenzenesulfonyl chloride yielded the protected serine intermediates, which on hydrogenolysis gave the desired L-serine analogs. By a similar route, 1,2-dihexadecyl- rac-glycero-3-phosphoric acid was converted to 1,2-dihexadecyl- rac-glycerophospho-L-serine [L-serine (±)-2,3-bis(hexadecyloxy)propyl hydrogen phosphate(ester)].