scholarly journals Multi-Component Crystals of 2,2′-Bipyridine with Aliphatic Dicarboxylic Acids: Melting Point-Structure Relations

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1151
Author(s):  
Vhukhudo Nethanani ◽  
Eustina Batisai
Keyword(s):  
Melting Point ◽  
Dicarboxylic Acids ◽  
Conformation Analysis ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Aliphatic Dicarboxylic Acids ◽  
The Relationship

The aim of the study was to investigate the relationship between the melting point and the supramolecular structure of three multi-component crystals of aliphatic dicarboxylic acids with 2,2′-bipyridine and to investigate the conformations of 2,2′-bipyridine in published multi-component crystals. The crystals were prepared using the solvent evaporation method and were characterized using single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). The crystal structures were further analyzed using CrystalExplorer, and the results were correlated with the melting points. The results of the conformation analysis of the reported multi-component crystals of 2,2′-bipyridine are also presented.

scholarly journals Improved Solubility of Vortioxetine Using C2-C4 Straight-Chain Dicarboxylic Acid Salt Hydrates

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 352 ◽  
Author(s):  
Lei Gao ◽  
Xian-Rui Zhang ◽  
Shao-Ping Yang ◽  
Juan-Juan Liu ◽  
Chao-Jie Chen
Keyword(s):  
Dicarboxylic Acid ◽  
Crystal Engineering ◽  
Dicarboxylic Acids ◽  
Acid Salt ◽  
X Ray Diffraction ◽  
Straight Chain ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Salt Hydrates ◽  
Aliphatic Dicarboxylic Acids

The purpose of this study was to improve the solubility of vortioxetine by crystal engineering principles. In this paper, three C2-C4 straight-chain dicarboxylic acid salt hydrates of vortioxetine (VOT-OA, VOT-MA-H2O, and VOT-SUA-H2O, VOT = vortioxetine, OA = Oxalic acid, MA = malonic acid, SUA = succinic acid) were synthesized and characterized by single X-ray diffraction, powder X-ray diffraction, and differential scanning calorimetry. The single crystal structure of three salts reveals that vortioxetine has torsional flexibility, which can encourage VOT to allow combination with aliphatic dicarboxylic acids through N+-H···O hydrogen bonds. The solubility of all salts exhibits a dramatic increase in distilled water, especially for VOT-MA-H2O salt, where it shows the highest solubility, by 96-fold higher compared with pure vortioxetine.

scholarly journals Stacking Control by Molecular Symmetry of Sterically Protected Phthalocyanines

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5552
Author(s):  
Ryota Kudo ◽  
Masahiro Sonobe ◽  
Yoshiaki Chino ◽  
Yu Kitazawa ◽  
Mutsumi Kimura
Keyword(s):  
Lamellar Structure ◽  
Synthesis And Characterization ◽  
Molecular Symmetry ◽  
X Ray Diffraction ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Structural Isomers ◽  
X Ray ◽  
Temperature Controlled

The synthesis and characterization of two phthalocyanine (Pc) structural isomers, 1 and 2, in which four 2,6-di(hexyloxy)phenyl units were attached directly to the 1,8,15,22- or 1,4,15,18-positions of the Pc rings, are described. Both Pcs 1 and 2 exhibited low melting points, i.e., 120 and 130 °C respectively, due to the reduction in intermolecular π-π interaction among the Pc rings caused by the steric hindrance of 2,6-dihexyloxybenzene units. The thermal behaviors were investigated with temperature-controlled polarizing optical microscopy, differential scanning calorimetry, powder X-ray diffraction, and absorption spectral analyses. Pc 1, having C4h molecular symmetry, organized into a lamellar structure containing lateral assemblies of Pc rings. In contrast, the other Pc 2 revealed the formation of metastable crystalline phases, including disordered stacks of Pcs due to rapid cooling from a melted liquid.

scholarly journals Biobased Poly(ethylene furanoate) Polyester/TiO2 Supported Nanocomposites as Effective Photocatalysts for Anti-inflammatory/Analgesic Drugs

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 564 ◽  
Author(s):  
Anastasia Koltsakidou ◽  
Zoi Terzopoulou ◽  
George Kyzas ◽  
Dimitrios Bikiaris ◽  
Dimitra Lambropoulou
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Transformation Products ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Analgesic Drug ◽  
Ion Release ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Anti Inflammatory ◽  
Poly Ethylene

In the present study, polymer supported nanocomposites, consisting of bio-based poly(ethylene furanoate) polyester and TiO2 nanoparticles, were prepared and evaluated as effective photocatalysts for anti-inflammatory/analgesic drug removal. Nanocomposites were prepared by the solvent evaporation method containing 5, 10, 15, and 20 wt% TiO2 and characterized using Fourier Transform Infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Thin films of them have been prepared by the melt press and optimization of the photocatalytic procedure was conducted for the most efficient synthesized photocatalyst. Finally, mineralization was evaluated by means of Total organic carbon (TOC) reduction and ion release, while the transformation products (TPs) generated during the photocatalytic procedure were identified by high-resolution mass spectrometry.

Study of an Energetic-oxidant Co-crystal: Preparation, Characterisation, and Crystallisation Mechanism

2017 ◽  
Vol 67 (5) ◽  
pp. 510 ◽  
Author(s):  
Han Gao ◽  
Wei Jiang ◽  
Jie Liu ◽  
Gazi Hao ◽  
Lei Xiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Diffraction Spectrum ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

<p>An energetic co-crystal consisting of the most promising military explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the most well-known oxidant applied in propellants ammonium perchlorate has been prepared with a simple solvent evaporation method. Scanning electron microscopy revealed that the morphology of co-crystal differs greatly from each component. The X-ray diffraction spectrum, FTIR, Raman spectra, and differential scanning calorimetry characterisation further prove the formation of the co-crystal. The result of determination of hygroscopic rate indicated the hygroscopicity was effectively reduced. At last, the crystallisation mechanism has been discussed.</p>

scholarly journals The Usefulness of X-ray Diffraction and Thermal Analysis to Study Dietary Supplements Containing Iron

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 197
Author(s):  
Izabela Jendrzejewska ◽  
Robert Musioł ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Joanna Klimontko ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Melting Point ◽  
Dietary Supplements ◽  
Polymorphic Form ◽  
Food Supplements ◽  
X Ray Diffraction ◽  
Iron Compounds ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Amorphous Compounds

X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.

scholarly journals Evaluation of Thermal-Induced Polymorphic Transformation on Desloratadine and Desloratadine-Benzoic Acid Salt

2020 ◽  
Vol 26 (4) ◽  
pp. 399-405
Author(s):  
Ahmad Ainurofiq ◽  
Rachmat Mauludin ◽  
Diky Mudhakir ◽  
Sundani Nurono Soewandhi
Keyword(s):  
Melting Point ◽  
Benzoic Acid ◽  
Polymorphic Transformation ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Physicochemical Changes ◽  
Transformation Methods

Background: Active pharmaceutical ingredients face a challenge in manufacturing due to adverse physicomechanical properties. Desloratadine (DES) form I exhibits poor mechanical behavior through the formation of capping during the tableting process. Salt formation from DES and benzoic acid (BA) has been observed to resolve poor mechanical properties. However, the ability to withstand heat from the manufacturing process should be implemented in DES and DES-BA salt. The aim of this study was to determine the differences between thermal treatment results on DES and DES-BA salt and whether it causes them to undergo polymorphic transformation. Methods: Salt was crystallized between DES and BA using the solvent evaporation method. DES and DES-BA salt were heated at 110°C, 159°C (melting point of DES), 181°C (melting point of DES-BA), and 190°C. Following this, characterization was performed using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and solubility testing. Results: Polymorphic transformation caused by heat occurred in DES, but not in DES-BA salt. The transformation of DES was induced by the effect of heating, which changed polymorph I to a mixture of polymorph I and III at 110°C, to polymorph II at 159°C, and to a mixture of polymorph I, II, and III at 190°C. Under 190oC, DES-BA is still stable and did not undergo a polymorphic transformation. However, at 190oC, decomposition started to occur, which implied decreased solubility, which did not occur in DES. Conclusion: The heating process did not cause DES-BA salt to undergo a polymorphic transformation. However, it caused decomposition at 190oC. DES underwent a polymorphic transformation when exposed to the same condition without decomposition. This provided information to always pay attention to temperature during manufacturing processes that include DES or DES-BA salt to avoid physicochemical changes.

Solvates of the antifungal drug griseofulvin: structural, thermochemical and conformational analysis

2013 ◽  
Vol 70 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Srinivasulu Aitipamula ◽  
Pui Shan Chow ◽  
Reginald B. H. Tan
Keyword(s):  
Melting Point ◽  
Solvent Free ◽  
Antifungal Drug ◽  
Free Form ◽  
Solution Stability ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Solvent Molecules ◽  
Solid Form

Four solvates of an antifungal drug, griseofulvin (GF), were discovered. All the solvates were characterized by differential scanning calorimetry, thermogravimetric analysis, and their crystal structures were determined by single-crystal X-ray diffraction. The solvents that form the solvates are acetonitrile, nitromethane and nitroethane (2:1 and 1:1). It was found that all the solvates lose the solvent molecules from the crystal lattice between 343 and 383 K, and that the melting point of the desolvated materials matched the melting point of the solvent-free GF (493 K). The conformation of the GF molecule in solvent-free form was found to be significantly different from the conformations found in the solvates. Solution stability studies revealed that the GF–acetonitrile solvate transforms to GF and that GF–nitroethane (1:1) solvate transforms to GF–nitroethane (2:1) solvate. On the other hand, GF–nitromethane and GF–nitroethane (2:1) solvates were found to be stable in solution. Our results highlight the importance of the co-crystallization technique in the pharmaceutical drug development; it not only expands the solid form diversity but also creates new avenues for unraveling novel solvates.

scholarly journals Melting Diagrams of Adefovir Dipivoxil and Dicarboxylic Acids: An Approach to Assess Cocrystal Compositions

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 70 ◽  
Author(s):  
Hyunseon An ◽  
Insil Choi ◽  
Il Kim
Keyword(s):  
Solid State ◽  
Adefovir Dipivoxil ◽  
Sufficient Conditions ◽  
Dicarboxylic Acids ◽  
Current Approach ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Solution Crystallization

Pharmaceutical cocrystallization is a useful method to regulate the physical properties of active pharmaceutical ingredients (APIs). Since the cocrystals may form in various API/coformer ratios, identification of the cocrystal composition is the critical first step of any further analysis. However, the composition identification is not always unambiguous if cocrystallization is performed in solid state with unsuccessful solution crystallization. Single melting point and some new X-ray diffraction peaks are necessary but not sufficient conditions. In the present study, the use of melting diagrams coupled with the X-ray diffraction data was tested to identify cocrystal compositions. Adefovir dipivoxil (AD) was used as a model API, and succinic acid (SUC), suberic acid (SUB), and glutaric acid (GLU) were coformers. Compositions of AD/SUC and AD/SUB had been previously identified as 2:1 and 1:1, but that of AD/GLU was not unambiguously identified because of the difficulty of solution crystallization. Melting diagrams were constructed with differential scanning calorimetry, and their interpretation was assisted by powder X-ray diffraction. The cocrystal formation was exhibited as new compositions with congruent melting in the phase diagrams. This method correctly indicated the previously known cocrystal compositions of AD/SUC and AD/SUB, and it successfully identified the AD/GLU cocrystal composition as 1:1. The current approach is a simple and useful method to assess the cocrystal compositions when the crystallization is only possible in solid state.

scholarly journals Studies on Cocrystal Formation of Metaxalone with Short-chain Dicarboxylic Acids

2014 ◽  
Vol 70 (a1) ◽  
pp. C658-C658
Author(s):  
Hong-Liang Lin ◽  
Tieh-Kang Wu ◽  
Yu-Ting Huang ◽  
Shan-Yang Lin
Keyword(s):  
Dicarboxylic Acids ◽  
Solvent Evaporation ◽  
Short Chain ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Evaporation Method ◽  
Ftir Microspectroscopy ◽  
One Step ◽  
Grinding Technique

A possible cocrystal formation between metaxalone and short-chain dicarboxylic acids (HOOC-(CH2)n-COOH, n=0-3) was quickly investigated using a solvent-assisted grinding approach. Differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) microspectroscopy, and powder X-ray diffraction (PXRD) were used to verify the cocrystal formation between metaxalone and each dicarboxylic acid. A solvent evaporation method was used to prepare the standard cocrystal. The cocrystal formation was also estimated by using a one-step simultaneous DSC-FTIR microspectroscopy. The present study indicates that only n=2 of short-chain dicarboxylic acids such as succinic acid, fumaric acid and maleic acid could form a cocrystal with metaxalone. Both solvent-assisted grinding technique and solvent evaporation method were successfully applied to prepare the metaxalone cocrystal with n=2 of short-chain dicarboxylic acids. Moreover, this cocrystal formation was also easily screened and estimated using a unique DSC-FTIR microspectroscopy in real time. Acknowledgement This work was supported by National Science Council, Taipei, Taiwan, ROC (NSC 100-2320-B- 264-001-MY3).

scholarly journals Molecular structure and rubber-like elasticity - III. Molecular movements in rubber-like polymers

1942 ◽  
Vol 180 (980) ◽  
pp. 82-99 ◽  
Keyword(s):  
Melting Point ◽  
X Ray Diffraction ◽  
Melting Points ◽  
Molecular Configuration ◽  
X Ray ◽  
Crystalline Polymers ◽  
Or Groups ◽  
Two Factors ◽  
Statistical Effects ◽  
Single Bonds

The evidence of X -ray diffraction photographs shows that in gutta-perch a and in polychloroprene at the ‘melting ’-point, major changes of molecular configuration due to rotation round the single bonds occur spontaneously. Melting is ascribed to the onset of chain-bond oscillation between alternative, geometrically equivalent positions (‘molecular wriggling’), and the low melting-points of these substances (and also, by analogy, of rubber) as compared with polyethylene are ascribed to the greater freedom of rotation round the single bonds in the former substances (and also, by analogy, of rubber) as com pared with polyethylene are ascribed to the greater freedom of rotation round the single bonds in the former substances. It is postulated that the energy required for rotation round the single bonds is made up of two factors— the bond-orientation energy, and the interaction of the atoms or groups held by the bonds. The comparative freedom of rotation in rubber and polychloroprene is due to two causes: first, the presence of double bonds in the chains, which has the effect of making rotation round adjacent single bonds m ore free than in comparable saturated molecules; an d secondly, the small hindrance to rotation offered by the side substituents. In gutta-perch a the bond-orientation energy is presumably the same as in rubber an d polychloroprene, but geometrical hindrance is greater, an d it is suggested that this is the reason for its rather higher melting-point. The structure of amorphous rubber is considered. Starting from the known structures of crystalline polymers, which consist of crystals tied together by molecules each of which passes through a number of crystals, the minimum change on melting is assumed, and that change— the wriggling an d consequent disarrangement of the molecules— is well founded on experimental evidence; it is not necessary to assume that the molecules have a completely random configuration, an d there are reasons why this is unlikely. The mechanical properties above and below the melting-point are correlated on this basis. The statistical effects to which Mark has drawn attention operate through the ‘tying ’ portions of the molecules.

Sign in / Sign up

Export Citation Format

Share Document