- Template-free synthesis of nanoporous gadolinium phosphonate as a magnetic resonance imaging (MRI) agent
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A new series of organic-inorganic hybrid porous gadolinium phosphonate (GdP) materials have been synthesized using benzene-1,3,5-triphosphonic acid as a phosphonic acid linker through a simple hydrothermal technique. The particle size and morphology are well controlled through the selection of suitable reaction conditions. The obtained materials exhibit very high specific surface area and crystalline pore walls with a triclinic structure having unit cell parameters a = 7.76 (3) ?; b = 8.60 (6) ?; c = 14.09 (7) ?; α = 100.08 (4)°; β = 84.23 (6)°; γ = 116.29 (6)°. The obtained GdP materials are further used as a magnetic resonance imaging (MRI) contrast agent with r1 and r2 values of 2.6 and 4.7 s-1 mM-1, respectively.
- Pramanik, Malay,Shieh, Fa-Kuen,Alshehri, Saad M.,Alothman, Zeid Abdullah,Wu, Kevin C.-W.,Yamauchi, Yusuke
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- Zirconium(IV)-Benzene Phosphonate Coordination Polymers: Lanthanide and Actinide Extraction and Thermal Properties
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Coordination polymers with different P/(Zr + P) molar ratios were prepared by combining aqueous solutions of Zr(IV) and benzenephosphonate derivatives. 1,3,5-Benzenetrisphosphonic acid (BTP) as well as phosphonocarboxylate derivatives in which carboxylate substitutes one or two of the phosphonate groups were chosen as the building blocks. The precipitates obtained on combining the two solutions were not X-ray amorphous but rather were indicative of poorly ordered materials. Hydrothermal treatment did not alter the structure of the materials produced but did result in improved crystalline order. The use of HF as a mineralizing agent during hydrothermal synthesis resulted in the crystallization of at least three relatively crystalline phases whose structure could not be determined owing to the complexity of the diffraction patterns. Gauging from the similarity of the diffraction patterns of all the phases, the poorly ordered precipitates and crystalline materials appeared to have similar underlying structures. The BTP-based zirconium phosphonates all showed a higher selectivity for lanthanides and thorium compared with cations such as Cs+, Sr2+, and Co2+. Substitution of phosphonate groups by carboxylate groups did little to alter the pattern of selectivity implying that selectivity in the system was entirely determined by the -POH group with little influence from the -COOH groups. Samples with the highest phosphorus content showed the highest extraction efficiencies for lanthanide elements, especially the heavy lanthanides such as Dy3+ and Ho3+ with separation factors of around four with respect to La3+. In highly acid solutions (4 M HNO3) there was a pronounced variation in extraction efficiency across the lanthanide series. In situ, nonambient diffraction was performed on ZrBTP-0.8 loaded with Th, Ce, and a complex mixture of lanthanides. In all cases the crystalline Zr2P2O7 pyrophosphate phase was formed at ~800 °C demonstrating the versatility of this structure.
- Luca, Vittorio,Tejada, Juan J.,Vega, Daniel,Arrachart, Guilhem,Rey, Cyrielle
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supporting information
p. 7928 - 7943
(2016/08/24)
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- Self-assembled titanium phosphonate nanomaterial having a mesoscopic void space and its optoelectronic application
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Here we report the synthesis of a new crystalline titanium phosphonate material (HTiP-7) having a self-assembled nanostructure and a mesoscopic void space without the aid of any surfactant or templating agent. The material has been synthesized hydrothermally through the reaction between benzene-1,3,5-triphosphonic acid (BTPA) and titanium(iv) isopropoxide at neutral pH at 453 K for 24 h. This hybrid phosphonate material has been thoroughly characterized by powder X-ray diffraction, N2 sorption, HR TEM, FE SEM, TG-DTA, FT IR and UV-Vis diffuse reflectance spectroscopic studies. Two very well-known software packages, REFLEX and CELSIZ unit cell refinement programs, are employed to establish the triclinic crystal phase of this hybrid material (HTiP-7). Very tiny nanocrystals of HTiP-7 self-aggregated to form spherical nanoparticles of dimension ca. 25 nm together with a mesoscopic void space and good BET surface area (255 m2 g-1). The framework is thermally stable up to 650 K. The material showed excellent carrier mobility for photocurrent generation in the presence of a photosensitizer molecule (Rose Bengal). To the best of our knowledge this is the first report of a photon-to-electron energy transfer process over a dye doped titanium phosphonate nanomaterial.
- Pramanik, Malay,Patra, Astam K.,Bhaumik, Asim
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p. 5140 - 5149
(2013/04/10)
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- Organic-inorganic hybrid supermicroporous iron(III) phosphonate nanoparticles as an efficient catalyst for the synthesis of biofuels
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Here we report a novel family of crystalline, supermicroporous iron(III) phosphonate nanomaterials (HFeP-1-3, HFeP-1-2, and HFeP-1-4) with different FeIII-to-organophosphonate ligand mole ratios. The materials were synthesized by using a hydrothermal reaction between benzene-1,3,5-triphosphonic acid and iron(III) chloride under acidic conditions (pH≈4.0). Powder X-ray diffraction, N2 sorption, transmission and scanning electron microscopy (TEM and SEM) image analysis, thermogravimetric and differential thermal analysis (TGA-DTA), and FTIR spectroscopic tools were used to characterize the materials. The triclinic crystal phase [P1(2) space group] of the hybrid iron phosphonate was established by a Rietveld refinement of the PXRD analysis of HFeP-1-3 by using the MAUD program. The unit cell parameters are a=8.749(1), b=8.578(1), c=17.725(3) ?; α=104.47(3), β=97.64(1), γ=113.56(3)°; and V=1013.41 ?3. With these crystal parameters, we proposed an 24-membered-ring open framework structure for HFeP-1. Compound HFeP-1-3, with an starting Fe/ligand molar ratio of 3.0, shows the highest Brunauer-Emmett-Telller (BET) surface area of 556 m2g -1 and uniform supermicropores of approximately 1.1 nm. The acidic surface of the porous iron(III) phosphonate nanoparticles was used in a highly efficient and recyclable catalytic transesterification reaction for the synthesis of biofuels under mild reaction conditions. Iron brews biofuels: Highly crystalline, supermicroporous iron(III) phosphonate nanoparticles have been synthesized through a hydrothermal reaction between benzene-1,3,5- triphosphonic acid and FeCl3. The resulting material was used as an efficient and recyclable catalyst for the synthesis of biofuels under mild reaction conditions (see scheme). Copyright
- Pramanik, Malay,Bhaumik, Asim
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p. 8507 - 8514
(2013/07/26)
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