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J M Tarascon - One of the best experts on this subject based on the ideXlab platform.
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comparative studies on the phase stability electronic structure and topology of the charge density in the li3xo4 x p as v lithium orthosalt Polymorphs
Chemistry of Materials, 2009Co-Authors: Christine Frayret, Christian Masquelier, Antoine Villesuzanne, Mathieu Morcrette, J M TarasconAbstract:Density functional theory (DFT) calculations within the generalized gradient approximation (GGA) were performed to study phase transitions in lithium orthosalts Li3XO4 (X = P, As, V). The equilibrium crystal structure parameters and the total energies of the Li3XO4 Polymorphs were calculated for the β- and γ-phases. The relative lattice stabilities of the two Polymorphs were examined in the light of various peculiarities at atomic scale. The β-Polymorph was systematically found to be the most stable one, agreeing well with experimental results. Using an all electron full potential method, we have investigated densities of states and the topology of charge density through the Bader’s quantum theory of “atoms in molecules” (AIM) along with electrostatic energy density maps in order to evaluate factors governing the stability of each Polymorph. Higher stability of the β-Polymorph or differences in energy between β- and γ-phases according to the nature of X along with the experimental temperatures of phase tr...
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Comparative studies on the phase stability, electronic structure, and topology of the charge density in the Li3XO4 (X = P, As, V) lithium orthosalt Polymorphs
Chemistry of Materials, 2009Co-Authors: Christine Frayret, Christian Masquelier, Antoine Villesuzanne, Mathieu Morcrette, J M TarasconAbstract:Density functional theory (DFT) calculations within the generalized gradient approximation (GGA) were performed to study phase transitions in lithium orthosalts Li3XO4 (X = P, As, V). The equilibrium crystal structure parameters and the total energies of the Li3XO4 Polymorphs were calculated for the β- and γ-phases. The relative lattice stabilities of the two Polymorphs were examined in the light of various peculiarities at atomic scale. The β-Polymorph was systematically found to be the most stable one, agreeing well with experimental results. Using an all electron full potential method, we have investigated densities of states and the topology of charge density through the Bader’s quantum theory of “atoms in molecules” (AIM) along with electrostatic energy density maps in order to evaluate factors governing the stability of each Polymorph. Higher stability of the β-Polymorph or differences in energy between β- and γ-phases according to the nature of X along with the experimental temperatures of phase transitions can be connected to several microscopic features, including differences in constraint within XO4 tetrahedron or chemical bonding characteristics. This new approach can be applied to other phase stability studies, including the family of Li2MSiO4, which is of great interest for cathode materials in lithium batteries.
Tejender S Thakur - One of the best experts on this subject based on the ideXlab platform.
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structural landscape guided exploration of a new Polymorph of 4 nitrobenzoic acid
Crystal Growth & Design, 2019Co-Authors: Sibananda G Dash, Shiv Shankar Singh, Tejender S ThakurAbstract:A structural landscape approach can be advantageous in the identification and assessment of the most probable Polymorphs of a given compound. However, the experimental realization of these putative Polymorphs remains a challenging endeavor. In this report, we present the utilization of a structural landscape study in the identification and characterization of a new Polymorph (form III) of 4-nitrobenzoic acid, which was obtained after 38 years. The reported Polymorph was first predicted from the crystal structure prediction computation, then validated by the fluoro substitution method, and finally realized experimentally by utilizing the information deduced from the landscape study. Additionally, the role of crystallizing solvent in promoting the crystal growth of the new Polymorph was studied using the Fourier transform infrared and fluorescence spectroscopic data, which sheds some light on the Polymorph selection in the solution.
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Structural Landscape-Guided Exploration of a New Polymorph of 4‑Nitrobenzoic Acid
2019Co-Authors: Sibananda G. Dash, Shiv Shankar Singh, Tejender S ThakurAbstract:A structural landscape approach can be advantageous in the identification and assessment of the most probable Polymorphs of a given compound. However, the experimental realization of these putative Polymorphs remains a challenging endeavor. In this report, we present the utilization of a structural landscape study in the identification and characterization of a new Polymorph (form III) of 4-nitrobenzoic acid, which was obtained after 38 years. The reported Polymorph was first predicted from the crystal structure prediction computation, then validated by the fluoro substitution method, and finally realized experimentally by utilizing the information deduced from the landscape study. Additionally, the role of crystallizing solvent in promoting the crystal growth of the new Polymorph was studied using the Fourier transform infrared and fluorescence spectroscopic data, which sheds some light on the Polymorph selection in the solution
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Crystal Polymorphism in Pharmaceutical Science
Comprehensive Supramolecular Chemistry II, 2017Co-Authors: Ranjit Thakuria, Tejender S ThakurAbstract:The phenomenon of crystal Polymorphism is of paramount importance to the pharmaceutical industry. Emergence of a new Polymorph can have deep implications on the solid form selection, regulation, and patentability aspects of a drug. This chapter provides a glimpse of some of the latest experimental technologies used to study crystal Polymorphism. Recent advances in computational methods for Polymorph prediction and some of the important regulatory and patentability aspects of Polymorphs are also discussed in the chapter.
Christine Frayret - One of the best experts on this subject based on the ideXlab platform.
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comparative studies on the phase stability electronic structure and topology of the charge density in the li3xo4 x p as v lithium orthosalt Polymorphs
Chemistry of Materials, 2009Co-Authors: Christine Frayret, Christian Masquelier, Antoine Villesuzanne, Mathieu Morcrette, J M TarasconAbstract:Density functional theory (DFT) calculations within the generalized gradient approximation (GGA) were performed to study phase transitions in lithium orthosalts Li3XO4 (X = P, As, V). The equilibrium crystal structure parameters and the total energies of the Li3XO4 Polymorphs were calculated for the β- and γ-phases. The relative lattice stabilities of the two Polymorphs were examined in the light of various peculiarities at atomic scale. The β-Polymorph was systematically found to be the most stable one, agreeing well with experimental results. Using an all electron full potential method, we have investigated densities of states and the topology of charge density through the Bader’s quantum theory of “atoms in molecules” (AIM) along with electrostatic energy density maps in order to evaluate factors governing the stability of each Polymorph. Higher stability of the β-Polymorph or differences in energy between β- and γ-phases according to the nature of X along with the experimental temperatures of phase tr...
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Comparative studies on the phase stability, electronic structure, and topology of the charge density in the Li3XO4 (X = P, As, V) lithium orthosalt Polymorphs
Chemistry of Materials, 2009Co-Authors: Christine Frayret, Christian Masquelier, Antoine Villesuzanne, Mathieu Morcrette, J M TarasconAbstract:Density functional theory (DFT) calculations within the generalized gradient approximation (GGA) were performed to study phase transitions in lithium orthosalts Li3XO4 (X = P, As, V). The equilibrium crystal structure parameters and the total energies of the Li3XO4 Polymorphs were calculated for the β- and γ-phases. The relative lattice stabilities of the two Polymorphs were examined in the light of various peculiarities at atomic scale. The β-Polymorph was systematically found to be the most stable one, agreeing well with experimental results. Using an all electron full potential method, we have investigated densities of states and the topology of charge density through the Bader’s quantum theory of “atoms in molecules” (AIM) along with electrostatic energy density maps in order to evaluate factors governing the stability of each Polymorph. Higher stability of the β-Polymorph or differences in energy between β- and γ-phases according to the nature of X along with the experimental temperatures of phase transitions can be connected to several microscopic features, including differences in constraint within XO4 tetrahedron or chemical bonding characteristics. This new approach can be applied to other phase stability studies, including the family of Li2MSiO4, which is of great interest for cathode materials in lithium batteries.
Patrick Mcardle - One of the best experts on this subject based on the ideXlab platform.
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Use of Sublimation Catalysis and Polycrystalline Powder Templates for Polymorph Control of Gas Phase Crystallization
2018Co-Authors: Naghmeh Kamali, Ciaran O’malley, Mary F. Mahon, Andrea Erxleben, Patrick McardleAbstract:In pursuit of a solvent-free green alternative to solution-based processes, we have applied the combined use of catalytic additives and polycrystalline powder templates for Polymorph control of gas phase crystallization to a range of pharmaceuticals and related compounds. Complementary volatile additives have been found that can catalyze the sublimation of a range of typical active pharmaceutical ingredients (APIs). Sublimation temperatures are typically reduced by up to 20 °C, and the process is accelerated. The use of polycrystalline powder templates for Polymorph control has also been successfully applied in several cases. Temperature control at the sites of both sublimation and desublimation is often required. The absence of even traces of solvent in the Polymorphs produced appears to give the samples higher stability than samples obtained by crystallization from solution. Complete Polymorph control was achieved with the following APIs, carbamazepine (five Polymorphs), metaxalone (two Polymorphs), mefenamic acid (two Polymorphs), paracetamol (two Polymorphs), and ortho-, meta-, and para-amino benzoic acids (one, four, and two Polymorphs respectively)
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17β hydroxy 17α methylandrostano 3 2 c pyrazole stanozolol the crystal structures of Polymorphs 1 and 2 and 10 solvates
Crystal Growth & Design, 2011Co-Authors: Jolanta Karpinska, Andrea Erxleben, Patrick McardleAbstract:17β-Hydroxy-17α-methylandrostano[3,2-c]pyrazole, also known as stanozolol, is a synthetic steroid derived from testosterone. Crystals grown by sublimation provide the first solvent free crystal structures of Polymorphs 1 and 2, and these are reported together with the structures of 10 solvates. Both Polymorphs contain voids. Polymorph 1 is more stable has a higher density and a smaller void than Polymorph 2 but also has unused hydrogen bonding capacity. The solvates exhibit a range of different hydrogen bonding networks and have no voids. Some of the structures have both tautomers of stanozolol present in the asymmetric unit.
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a method for the prediction of the crystal structure of ionic organic compounds the crystal structures of o toluidinium chloride and bromide and Polymorphism of bicifadine hydrochloride
CrystEngComm, 2004Co-Authors: Patrick Mcardle, Karen Gilligan, Desmond Cunningham, Rex Dark, Mary F. MahonAbstract:The crystal structures of o-toluidinium chloride (1), o-toluidinium bromide (2) and two Polymorphs of bicifadine hydrochloride (3) have been determined. The Polymorphs of 3 differ in their molecular conformation and in their mode of packing. Crystallisation studies and quantum mechanical calculations show that the more readily crystallisable Polymorph grows from the thermodynamically most stable conformer. On heating, conversion to the second Polymorph takes place just below the melting point. The crystal structures of 1, 2 and the first Polymorph of 3 have been successfully predicted using a procedure that is suitable for simple ionic organics.
Ronald Melki - One of the best experts on this subject based on the ideXlab platform.
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Differential Membrane Binding and Seeding of Distinct $\alpha$-Synuclein Fibrillar Polymorphs
Biophysical Journal, 2020Co-Authors: Amulya Nidhi Shrivastava, Luc Bousset, Marianne Renner, Virginie Redeker, Jimmy Savistchenko, Antoine Triller, Ronald MelkiAbstract:The aggregation of the protein $\alpha$-Synuclein ($\alpha$-Syn) leads to different synucleinopathies. We recently showed that structurally distinct fibrillar $\alpha$-Synuclein Polymorphs trigger either Parkinson’s Disease or Multiple System Atrophy hallmarks in vivo. Here, we establish structural-molecular basis for these observations. We show that distinct fibrillar $\alpha$-Syn Polymorphs bind to and cluster differentially at the plasma membrane in both primary neuronal cultures and organotypic hippocampal slice cultures from wild-type mice. We demonstrate $\alpha$ Polymorph-dependent and concentration-dependent seeding. We show a Polymorph-dependent differential synaptic re-distribution of $\alpha$3-Na$^+$/K$^+$-ATPase, GluA2- AMPA and GluN2B-NMDA receptors but not GluA1-AMPA and mGluR5 receptors. We also demonstrate Polymorph-dependent alteration in neuronal network activity upon seeded aggregation of $\alpha$-Syn. Our findings bring new insight into how distinct $\alpha$-Syn Polymorphs differentially bind to and seed monomeric $\alpha$-Syn aggregation within neurons, thus affecting neuronal homeostasis through the redistribution of synaptic proteins
