Titanium Phosphonate Research Articles

A Tripodal Peptidic Titanium Phosphonate as a Homochiral Porous Solid Medium for the Heterogeneous Enantioselective Hydration of Epoxides

AbstractA porous, homochiral titanium‐phosphonate material based on a tripodal peptide scaffold was used as a heterogeneous reaction medium for the enantioselective hydration (>99%) of styrene oxide. This titanium‐phosphonate material, which was shown to contain confined chiral spaces, was prepared by polymerization of L‐leucine onto a tris(2‐aminoethyl)amine initiator, followed by capping with phosphonate groups and completed by non‐aqueous condensation with titanium isopropoxide. Circular dichroism confirmed that the peptide tethers yielded a secondary structure. X‐ray powder diffraction and transmission electron microscopy supported by a semi‐empirical model showed the likely formation of a porous, lamellar material that was quantified by nitrogen adsorption.

Synthesis and Photocatalytic Performance of Hierarchical Porous Titanium Phosphonate Hybrid Materials

A hierarchical meso-/macroporous titanium phosphonate (TPPH) hybrid material was prepared via a simple surfactant-assisted process with the use of the precursor tetrabutyl titanate and 1-hydroxy ethylidene-1,1-diphosphonic acid. The prepared hybrid TPPH presented amorphous phase, exhibiting a hierarchical macroporous structure composed of mesopores with a pore size of 2.0 nm. The BET surface area is 256 m2/g. The hydroxyethylidene-bridged organophosphonate groups were homogeneously incorporated in the network of the hierarchical porous solid, as revealed by FT-IR, MAS NMR, XPS, and TGA measurements. The optical properties and photocatalytic activity of the hierarchical TPPH material were investigated in comparison with those of hierarchical porous titanium phosphate and pure mesoporous titania materials, showing superiority of the inorganic-organic hybrid framework, suggesting promising photocatalysts for wastewater cleanup.

Cubic Mesoporous Titanium Phosphonates with Multifunctionality

Cubic mesoporous titanium phosphonate materials with bridged organic groups inside the framework were synthesized by means of a one-pot hydrothermal autoclaving process, with the assistance of cationic surfactant cetyltrimethylammonium bromide. 1-Hydroxyethylidene-1,1-diphosphonic acid was used as the coupling molecule. A typical cubic mesophase with surface area of 1052 m(2) g(-1) and pore size of 2.6 nm was confirmed by XRD, TEM, and N(2) sorption analysis. The organophosphonate groups were homogeneously incorporated in the network of the mesoporous solids, as revealed by FTIR and magic-angle spinning (MAS) NMR spectroscopy, and thermogravimetry and differential scanning calorimetry (TG-DSC) measurements. The synthesized hydroxyethylidene-bridged cubic mesoporous titanium phosphonates proved to be thermally stable up to 350 degrees C, with a well-preserved hybrid framework and cubic mesoporous architecture. The obtained cubic mesophase could be transformed into a hexagonal mesophase by simply adjusting the molar ratios of the added raw materials, namely, a Ti/P molar ratio of 1:4 and a CTAB/Ti molar ratio of 1.9-2.3 for the cubic phase and Ti/P molar ratio of 3:4 and CTAB/Ti molar ratio of 0.1-0.4 for the hexagonal phase. The cubic hybrid materials could be used as efficient photocatalysts for the photodegradation of rhodamine B. Moreover, they were also used for adsorption of CO(2) and heavy metal ions and exhibited a significant capture amount of around 1.0 mmol g(-1) for CO(2) molecules at 35 degrees C and high adsorption capacity of 28.5 micromol g(-1) for Cu(2+) ions with good reusability, which demonstrated their promising potential in environmental remediation.

Organic‐Additive‐Assisted Synthesis of Hierarchically Meso‐/Macroporous Titanium Phosphonates

AbstractOrganic‐inorganic hybrid materials of meso‐/macroporous titanium triphosphonate materials were synthesized by using amino tri(methylene phosphonic acid) as the coupling molecule. The preparation was accomplished by a hydrothermal process in the presence or absence of small amounts of the diblock copolymer EO30PO34 and β‐cyclodextrin as the organic additives. The organic‐additive‐assisted preparation efficiently aided the enlargement of the surface areas and pore volumes of the resultant porous titanium triphosphonates and helped improve the wormhole‐like mesoporosity. In addition to the large macrochannels, with a size of 500–1000 nm, observed in all the titanium phosphonates synthesized with or without organic additives, a secondary small‐scaled, spherical macroporous structure with a diameter of 50–100 nm was obtained by the addition of cyclodextrin. These macroporous structures are proposed to be templated by the aggregation of cyclodextrin. The structural characterization confirms the integrity of organic groups inside the framework. Large adsorption capacities for heavy metal ions and CO2 are demonstrated in these hybrid materials, which makes them promising adsorbents for practical applications.

Periodic mesoporous titanium phosphonate hybrid materials

Periodic mesoporous titanium phosphonate materials (PMTP-1) with bridged-organic groups inside the framework are synthesized by an autoclaving process combined with the evaporation-induced self-assembly (EISA) strategy, with the assistance of surfactant Brij 56 (C16EO10). Sodium salt of ethylene diamine tetra(methylene phosphonic acid) (EDTMPS) is used as the coupling molecule. A typical hexagonal mesophase is confirmed by TEM, N2 sorption and XRD analysis. The organophosphonate groups are homogeneously incorporated in the network of the mesoporous solids, as revealed by FT-IR, MAS NMR, TG-DSC and XPS measurements. The calcination experiments also prove that the hexagonal mesoporous titanium phosphonates are thermally stable up to 450 °C, and then transformed into inorganic hexagonal mesoporous titanium phosphates. The PMTP-1 hybrid materials can be used as useful photocatalysts for organic dye degradation and also as efficient adsorbents for heavy metal ions, which follow Langmuir-type behavior exhibiting innate selective affinity for the adsorption of Cu2+ over Pb2+ and Cd2+ ions, demonstrating their promising potential in environmental remediation.

High surface area titanium phosphonate materials with hierarchical porosity for multi-phase adsorption

Inorganic–organic hybrid titanium phosphonate materials with a hierarchically-porous structure were synthesized by a mild solvent evaporation strategy using 1-hydroxyethylidene-1,1-diphosphonic acid as an organophosphorus coupling molecule. The preparations were accomplished with the use of triblock copolymers F127 and P123 as structure-directing agents. All the samples possessed a macroporous morphology of the mesoporous framework with a high surface area, and were characterized by SEM, TEM and N2 sorption analysis. The hydroxyethylidene-bridged organophosphonate groups were homogeneously incorporated into the network of the hierarchical porous solid, as revealed by FT-IR, MAS NMR, TGA-DSC and XPS measurements. The hybrid materials were used as adsorbents for the liquid phase adsorption of Cu2+ ions in water and the gas phase adsorption of CO2, showing high adsorption capacity and good reusability, which makes them promising adsorbents for practical applications in environmental remediation.

Periodic mesoporous titanium phosphonate spheres for high dispersion of CuO nanoparticles

Periodic mesoporous titanium phosphonate spheres are prepared in the presence of surfactant Brij 56 by utilizing sodium salt of ethylene diamine tetra(methylene phosphonic acid) as the coupling molecule. The spherical morphology could be only obtained with the water-ethanol ratio of 75/25. The synthesized hybrids possess periodic mesoporosity with specific surface area of 606 m(2) g(-1) and irregular macrovoids throughout the microspheres, revealed by the measurements of X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy. The structure and chemical states of the materials are characterized by chemical analysis, FT-IR, MAS NMR, XPS and thermogravimetric analysis, indicating the homogeneous integrity of organic groups inside the hybrid framework, which allows Cu(2+) ions extensively coordinated with these organic ligands. The monolayer adsorption behavior of Cu(2+) ions is confirmed, and further calcination of the Cu(2+) ion-dispersed matrix results in the highly dispersed CuO active components on the pore surface of mesoporous titanium phosphonates. The H(2)-TPR analysis and catalytic CO oxidation testing prove that the CuO nanoparticles, dispersed on either hybrid or inorganic supports, prepared by this coordination and calcination strategy, possess high oxidation activity, making them promising catalysts for potential environmental applications.

Functionalized periodic mesoporous titanium phosphonate monoliths with large ion exchange capacity

Periodic mesoporous titanium phosphonate (PMTP-2) monoliths were synthesized by combining autoclaving process and evaporation-induced self-assembly strategy, which was functionalized by ClSO(3)H treatment, acting not only as an ion exchanger with large ion exchange capacity but also as a strong acid catalyst possible for some low-temperature reactions.

High selectivity for metal ion adsorption: from mesoporous phosphonated titanias to meso-/macroporous titanium phosphonates

A family of hybrid surface-phosphonated titania, titania–phosphonate, and titanium phosphonate porous materials with different organic groups in the network was synthesized by utilizing a series of organophosphonic acids as the coupling molecules. The crystalline degree of the obtained hybrids decreased by increasing the original added coupling molecule amount, with the structural phase transformed from phosphonated titania to titanium phosphonate, and simultaneously the nanoarchitecture changed from mesoporous to hierarchically meso-/macroporous structure. The whole synthesis process was performed under a very wide pH range by a template-free strategy. The samples were characterized by XRD, N2 sorption, SEM, TEM, FT-IR, MAS NMR, XPS, and TG-DSC analysis. It is revealed that the integrity of organic groups remained inside the framework of the synthesized hybrids. All the synthesized adsorbents exhibited large capacity of heavy metal ion adsorption with a definite selectivity, which depended on the nature and positions of organically functional groups.

Hierarchically meso-/macroporous titanium tetraphosphonate materials: Synthesis, photocatalytic activity and heavy metal ion adsorption

Hierarchically meso-/macroporous titanium tetraphosphonate materials with intraframework ethylenediamine groups were synthesized by a simple surfactant-free process with the use of sodium salt of ethylene diamine tetra(methylene phosphonic acid) and titanium tetrabutoxide precursors under a very wide pH range from pH = 3–13. Besides the macroporous structure of 100–300 nm in size, a wormhole-like mesostructure was in the macropore surface layers of the framework and a mesocellular foam structure in the core part of the macroporous walls, rendering an unusual hierarchical structure of titanium phosphonates, which was supported by the electron microscopic observation and nitrogen adsorption analysis. Characterization by FT-IR, NMR and XPS indicated the integrity of the organophosphonate groups in the macro-/mesoporous solid. The synthesized materials exhibited not only high photocatalytic activity under UV-light irradiation, but also large capacity for heavy metal ion adsorption with a preference sequence of Cd 2+ < Cu 2+ < Pb 2+ and effective regeneration ability, suggesting very promising photocatalysts for organic waste degradation and adsorbents for metal ion recovery and wastewater cleanup.

Profiling of Endogenous Serum Phosphorylated Peptides by Titanium (IV) Immobilized Mesoporous Silica Particles Enrichment and MALDI-TOFMS Detection

Phosphorylation is one of the most important post-translational modifications of proteins, which modulates a wide range of biological functions and activities of proteins. The phosphorylation of proteins is also associated with the pathway of cancer cells. We have previously enriched the low molecular weight proteome from human plasma based on the combination of size exclusion and adsorption mechanism by using highly ordered mesoporous silica particles. Herein, highly ordered mesoporous silica particles were modified with titanium phosphonate to selectively capture the phosphopeptides from complex peptide and protein mixtures. The limit of detection for phosphopeptides from beta-casein and standard phosphopeptide spiked in human serum was as low as 1.25 fmol based on MALDI-TOFMS detection. The modified mesoporous silica particles were further used to enrich phosphopeptides from serum of hepatocellular carcinoma patients and healthy individuals and then analyzed with MALDI-TOFMS. The combination of isobaric tagging for relative and absolute quantitation labeling with MALDI-TOFMS/MS was further applied to validate the serum phosphopeptide profiling result of MALDI-TOFMS. The profiling of the serum phosphopeptides between the cancer patients and healthy persons was distinguishingly different, which indicated the potential ability of this technique for cancer diagnosis and biomarker discovery. The approach developed here would be applicable to other biological samples and a wide variety of diseases.

Ordered Macroporous Titanium Phosphonate Materials: Synthesis, Photocatalytic Activity, and Heavy Metal Ion Adsorption

A three-dimensionally ordered macroporous titanium phosphonate material (TOP) was synthesized by an inverse opal method using 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP). The β-cyclodextrin (β-CD)-added derivative (TOPβ) with hydroxy ethylidene groups inside the frameworks was also performed, having morphology modification and catalytic and adsorptive ability improvement. The samples were characterized by SEM, TEM, XRD, TG-DTA, FT-IR, and UV−vis absorption spectroscopy techniques. The introduced macroporous structure and the presence of the phosphorus and organic groups within the titanium phosphonate framework are believed to contribute the improvement of photocatalytic activity and heavy metal ion adsorption ability, demonstrated by the photodecomposition of Rhodamine B and the adsorption test of Cu2+, Cd2+, and Pb2+, respectively. A comparable photocatalytic activity with commercial P-25 and a selective complexation affinity for Cu2+ were observed in the synthesized hybrid materials, suggesting t...

27Al, 47,49Ti, 31P, and 13C MAS NMR Study of VX, GD, and HD Reactions with Nanosize Al2O3, Conventional Al2O3 and TiO2, and Aluminum and Titanium Metal

Reactions of VX, GD, and HD with Al2O3, TiO2 (anatase and rutile), aluminum, and titanium metal powders have been studied by 27Al, 47,49Ti, 31P, and 13C MAS NMR. VX, GD, and HD hydrolyze on both nanosize and conventional Al2O3. A significant droplet size effect on the reaction kinetics is observed. For VX and GD, 27Al and 31P MAS NMR detect the formation of aluminum phosphonate complexes. Similarly, GD hydrolysis on TiO2 yields titanium phosphonate species as detected by 31P MAS NMR. Attempts at obtaining 47,49Ti NMR spectra of these species and those of titanium phosphonate model compounds at 14 T were marginally successful. 47,49Ti NMR spectra were obtainable for anatase and titanium metal; thus, severe second-order quadrupolar linebroadening is suspected for the titanium phosphonate complexes. 47,49Ti NMR spectra obtained for anatase at high magnetic field (17.5 and 21 T) showed anticipated improvement in peak width and resolution. GD reacted with aluminum and titanium powder in the presence of water results in acid-dissolution of the metals and the formation of their respective metal phosphonates.

A novel type of chiral titanium phosphonates and hybrid titanium phosphonates for heterogeneous asymmetric catalysis

(1R, 2S)-(−)-2-amino-1, 2-diphenylethanol and (1S, 2R)-(+)-2-amino-1, 2-diphenylethanol had been immobilized on the layered titanium phosphonates 4a–d and hybrid titanium phosphonates 5a–c in spheroid form with interlayer space 20.845–19.407 A which can be used as heterogeneous catalysts in the enantioseletive addition of diethylzinc to benzaldehyde to obtain optically active (R)-or (S)-1-phenylpropan-1-ol for the first time. It was shown that the titanium phosphonate 4a led to active heterogeneous catalysis for asymmetric additions of diethylzinc to benzaldehydes in 88.5% yield and ee value of up to 40.8% which decreased at 16% ee lower than corresponding chiral ligand in homogeneous asymmetric catalysis. AFM showed that the distribution of 1,2-dipenyl-2-aminoethanol organic moieties on the surface of titanium phosphonates irregularly lined like flow mark.

Titanium Phosphonate Porous Materials Constructed from Dendritic Tetraphosphonates

An organic-inorganic hybrid material, TPPhA-Ti, was constructed by non-hydrolytic condensation of a dendritic tetrakis-1,3,5,7-(4-phosphonatophenyl)adamantane precursor and titanium(IV) isopropoxide. One preparative pathway yielded insoluble materials with a Ti/P ratio of approximately 1 which was confirmed by a combination of FT-IR, TGA, and EDS measurements. N2 sorption experiments showed that TPPhA-Ti is a porous solid (micropores approximately 13 A; mesopores approximately 38 A) with a high surface area, approximately 550 m2 g(-1). The structure and morphology of the TPPhA-Ti as investigated by transmission and scanning electron microscopy showed a layered-type material. Additional X-ray diffraction data suggest a paracrystalline material; an optimization of possible molecular arrangements of TPPhA-Ti was simulated that was in agreement with the experimental data. A second preparative pathway yielded a Ti oxide-phosphonate with a Ti/P ratio of approximately 3.4. Both TEM and SEM revealed that hollow nanospheres were formed with diameters of approximately 180-300 nm.

Development of ion-sensitive field-effect transistor-based sensors for benzylphosphonic acids and thiophenols using molecularly imprinted TiO 2 films

Molecularly imprinted polymeric membranes, containing artificial recognition sites for a number of benzylphosphonic acid derivatives, were prepared by the polymerization of titanium(IV) butoxide in the presence of a titanium(IV) phosphonate complex. Reference polymers were prepared in the same manner but in the absence of the phosphonate template. FTIR spectroscopy was used to follow the formation of a benzylphosphonic acid–Titanium(IV) oxide complex during the imprinting process, and upon the association of the substrate in the imprinted TiO 2 thin film. The imprinted polymers were examined as sensing membranes in an ion-sensitive field-effect transistors (ISFETs). The sensors reveal selectivity towards analyzing the imprinted substrates, yet the recognition ability of the sensors strongly depends on the substituents associated with the phosphonic acid structures. The response time of the sensors is ca. 45 s, and the sensors reveal unaffected stability for at least 2 weeks. Also, imprinted TiO 2 films for thiophenol, and para-nitrothiophenol were generated on ISFET devices, and the respective substrates were selectively sensed by the functional devices.

Preparation, characterization and proton conductivity of titanium phosphate sulfophenylphosphonate

Titanium phosphate sulfophenylphosphonate, Ti(HPO 4) 1.00(O 3PC 6H 4SO 3H) 0.85(OH) 0.30· nH 2O was synthesised and characterized by X-ray diffraction, solid state NMR, impedance measurements, TG and DSC analysis. The MAS-NMR spectrum of 31P nucleus presents two resonances characteristic of monohydrogen phosphate and sulfophenylphosphonate groups coordinated to three Ti(IV) atoms through three non-protonated oxygen atoms. Water content, protonic conductivity ( σ) and activation energy for conduction ( E a) were determined in the range 20 to −20°C for materials equilibrated at relative humidity (r.h.) in the range 5–90%. By increasing the number of water molecules per sulfonic group from 2 to 14, σ rises by 3 orders of magnitude up to about 0.1 S cm −1, while E a decreases from 12.6 to 4.3 kcal/mol. Measurements were also carried out at 100°C as a function of relative humidity in the range 30–100%; σ values higher than 0.1 S cm −1 were found at r.h. ≥65%. The titanium phosphonate was used as a filler of Nafion 1100 hybrid membranes. At 100°C and 80% r.h., the conductivity of the hybrid membranes containing from 5% to 20% phosphonate loading is very similar to that of a Nafion 1100 membrane prepared in-house by casting technique, but it drops by an order of magnitude when the loading is increased to 30%.

Carbanions Substituted by Transition Metals: Synthesis, Structure, and Configurational Restrictions of a Lithium Titanium Phosphonate

Carbanions Substituted by Transition Metals: Synthesis, Structure, and Configurational Restrictions of a Lithium Titanium Phosphonate

Carbanions Substituted by Transition Metals: Synthesis, Structure, and Configurational Restrictions of a Lithium Titanium Phosphonate.

The titanium-stabilized lithium carbanion 1 represents a new class of organodimetallic compounds that are easily accessible by a dilithiation–transmetalation sequence [Eq. (1)]. The X-ray structure of 1 revealed an aggregate consisting of two titanated lithium phosphonate units and two molecules of LiCl as the aggregation nucleus. Density functional calculations on a model system showed excellent agreement with the solid-state structure and suggest a configurational stability comparable to those of lithium phosphonates.

Syntheses, characterizations, and single-crystal X-ray structures of soluble titanium alkoxide phosphonates.

Reactions of Ti(OiPr)4 with different phosphonic acids RPO3H2 (R = Ph, 4-CNPh, Me, tBu) in organic solvents have been investigated. In the presence of small amounts of water, the new molecular titanium oxide alkoxide phosphonates [Ti4(mu 3-O)(OiPr)5(mu-OiPr)3(RPO3)3].DMSO [R = Ph (1), Me (2), tBu (3), 4-CNPh (4)] were isolated. The single-crystal X-ray structure analyses of 1 and 2 revealed hexacoordinated titanium atoms and a connectivity of (111) for each phosphonate. Under rigorous exclusion of water, the reaction of Ti(OiPr)4 with tert-butylphosphonic acid in toluene gave the titanium phosphonate tetramer [Ti(OiPr)2(tBuPO3)]4 (5). A single-crystal X-ray structure analysis of 5 revealed a 5 + 1 coordination of the titanium atoms as a result of the (112) connectivity of each phosphonate; such a coordination mode has never been reported for a titanium phosphate, phosphonate, or phosphinate. Compounds 1-5 were characterized by FT-IR, 31P MAS NMR, and solution multinuclear NMR (1H, 13C(1H,) 31P(1H)) spectroscopies. 13C CP MAS NMR experiments were carried out on arylphosphonates 1 and 4. Solution NMR experiments were also used to investigate the exchange reaction between 1 and 2 and the conversion of 5 to [Ti4(mu 3-O)(OiPr)5(mu-OiPr)3(tBuPO3)3].iPrOH by partial hydrolysis in the presence of Ti(OiPr)4. The phosphonate clusters 1-5 are soluble in organic solvents and are likely intermediates in the sol-gel processing of inorganic-organic hybrids based on titanium oxide and phosphonate groups that we are currently developing.