Peptides

Smith, Robert M.; Martell, Arthur E.

doi:10.1007/978-1-4615-6764-6_3

Cited by 2 publications

(4 citation statements)

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“…These authors presuppose the previous formation of a Bi(III)–tartrate complex that is further deprotonated by the addition of a NaOH solution. The higher affinity of Bi(III) for hydroxyl groups (log K = 32.8, for Bi(III)/4OH –1 ) than for tartrate ions (log K = 0.9) and their concentration differences favor, at least, the partial replacement of the linked tartrate groups from the Bi(III) complexes; therefore, not only the deprotonation process takes place as these authors claim. Once again, the high concentration of NaOH helps the remanence of Bi(III)-hydroxyl species after the reduction reaction or its formation on the Bi NPs surfaces. , The shoulder observed by D. Ma et al in the absorption spectrum suggests the presence of Bi(III)-hydroxyl species.…”

Section: Resultsmentioning

confidence: 95%

Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions

et al. 2012

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This report outlines the synthesis of zerovalent bismuth nanoparticle (ZV-Bi NP) colloidal dispersions, in dimethyl sulfoxide. For the general preparation pathway of these colloids, a commercial bismuth(III) salt and also a conventional reducing agent were used. All reactions took place immediately and under mild conditions. Stable, for more than three months, under room conditions, ZV-Bi NP colloids are obtained when using sodium citrate and a deficit of the reducing agent respect to the bismuth salt. This reaction mixture yields small, well-faceted, and also quasi-spherical crystalline particles, with an average size of 3.3 nm, SD of 1.0 nm, determined by HR-TEM. These are the smallest ZV-Bi NPs, synthesized by a fast and straightforward colloidal method, found in the literature. Indirect and direct energy gaps were discovered in the near-infrared spectral range (1400–1600 nm) of the ZV-Bi NPs, indicating the displacement of the conduction and valence bands due to the strong quantum confinement; bulk bismuth itself is a semimetal. This is the first time that energy gaps of quantum confined ZV-Bi NPs are found at room conditions. The dry ZV-Bi NP powders that precipitated from the colloids are totally stable in storage, at room conditions, for more than three years.

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Section: Resultsmentioning

confidence: 95%

Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions

et al. 2012

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“…The anion of the l -(+)-tartaric acid and Bi 3+ form polymeric chains with a nine-coordinate bismuth center (BiO 9 ). , However, the tartrate anion does not have the same affinity for Bi 3+ and Fe 3+ . ,, Consequently, the two cations do not get homogeneously distributed in the polymeric chains in the precursor solutions. This could be a new possible explanation for the formation of Bi 2 O 3 and Bi 2 Fe 4 O 9 byproducts, or a different Bi/Fe atomic ratio from 1:1 in the BiFeO 3 NPs, obtained during the combustion reaction.…”

Section: Results and Discussionmentioning

confidence: 99%

“…This is the main difference observed between the use of glycine or tartaric acid for the synthesis. The reasons for this pathway differentiation might be the following: (a) There is a homogeneous distribution of the Fe(III)–glycine and Bi(III)–glycine complexes due to the similar affinity constants that the glycinate anion has for the cations (Fe 3+ , Bi 3+ , and H + ). , (b) The glycinate anion competes with NO 3 1– and interrupts the formation of the 3D networks of bismuth oxide clusters, like [Bi 6 O 4 (OH) 4 (NO 3 ) 6 (H 2 O)]·H 2 O . The latter forms bismuth oxide when decomposed under annealing.…”

Section: Results and Discussionmentioning

confidence: 99%

“…This process is straightforward, simple, energy-saving, and cost-effective. An integral discussion about the role of glycinate ion as ligand, which has the same affinity constant for Fe 3+ and Bi 3+ (log K = 10) , and slightly lower for H + (log K = 9.57), was accomplished. After a thorough characterization of the BiFeO 3 NPs by powder XRD, SEM, HRTEM, TGA, VSM, and UV–vis electronic absorption, Raman scattering, Mössbauer, and EPR spectroscopies, we obtained very interesting experimental results and offer consistent interpretations of the physicochemical properties of these ferrite NPs.…”

Section: Introductionmentioning

confidence: 99%

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Easy Synthesis of High-Purity BiFeO₃Nanoparticles: New Insights Derived from the Structural, Optical, and Magnetic Characterization

Díaz²,

et al. 2013

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Synthesis of high-purity BiFeO3 is very important for practical applications. This task has been very challenging for the scientific community because nonstoichiometric Bi(x)Fe(y)O(z) species typically appear as byproducts in most of the synthesis routes. In the present work, we outline the synthesis of BiFeO3 nanostructures by a combustion reaction, employing tartaric acid or glycine as promoter. When glycine is used, a porous BiFeO3 network composed of tightly assembled and sintered nanocrystallites is obtained. The origin of high purity BiFeO3 nanomaterial as well as the formation of other byproducts is explained on the basis of metal-ligand interactions. Structural, morphological, and optical analysis of the intermediate that preceded the formation of porous BiFeO3 structures was accomplished. The thorough characterization of BiFeO3 nanoparticles (NPs) included powder X-ray diffraction (XRD); scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM); thermogravimetric analysis (TGA); UV-vis electronic absorption (diffuse reflectance mode), Raman scattering, Mössbauer, and electron paramagnetic resonance (EPR) spectroscopies; and vibrating sample magnetometry (VSM). The byproducts like β-Bi2O3 and 5 nm Bi2Fe4O9 NPs were obtained when tartaric acid was the promoter. However, no such byproducts were formed using glycine in the synthesis process. The average sizes of the crystallites for BiFeO3 were 26 and 23 nm, for tartaric acid and glycine promoters, respectively. Two band gap energies, 2.27 and 1.66 eV, were found for BiFeO3 synthesized with tartaric acid, obtained from Tauc's plots. A remarkable selective enhancement in the intensity of the BiFeO3 A1 mode, as a consequence of the resonance Raman effect, was observed and discussed for the first time in this work. For glycine-promoted BiFeO3 nanostructures, the measured magnetization (M) value at 20,000 Oe (0.64 emu g(-1)) was ∼5 times lower than that obtained using tartaric acid. The difference between the M values has been associated with the different morphologies of the BiFeO3 nanostructures.

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Peptides

Cited by 2 publications

References 234 publications

Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions

Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions

Easy Synthesis of High-Purity BiFeO₃Nanoparticles: New Insights Derived from the Structural, Optical, and Magnetic Characterization

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Peptides

Cited by 2 publications

References 234 publications

Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions

Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions

Easy Synthesis of High-Purity BiFeO3Nanoparticles: New Insights Derived from the Structural, Optical, and Magnetic Characterization

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Easy Synthesis of High-Purity BiFeO₃Nanoparticles: New Insights Derived from the Structural, Optical, and Magnetic Characterization