scholarly journals Organoelement Compounds Crystallized In Situ: Weak Intermolecular Interactions and Lattice Energies

Crystals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Alexander D. Volodin ◽  
Alexander A. Korlyukov ◽  
Alexander F. Smol’yakov
Keyword(s):  
Melting Point ◽  
Intermolecular Interactions ◽  
Crystal Packing ◽  
Molecular Surface ◽  
Organofluorine Compounds ◽  
Melting Points ◽  
Halogen Atoms ◽  
Surface Areas ◽  
Lattice Energies

The in situ crystallization is the most suitable way to obtain a crystal of a low-melting-point compound to determine its structure via X-Ray diffraction. Herein, the intermolecular interactions and some crystal properties of low-melting-point organoelement compounds (lattice energies, melting points, etc.) are discussed. The discussed structures were divided into two groups: organoelement compounds of groups 13–16 and organofluorine compounds with other halogen atoms (Cl, Br, I). The most of intermolecular interactions in the first group are represented by weak hydrogen bonds and H···H interactions. The crystal packing of the second group of compounds is stabilized by various interactions between halogen atoms in conjunction with hydrogen bonding and stacking interactions. The data on intermolecular interactions from the analysis of crystal packing allowed us to obtain correlations between lattice energies and Hirshfeld molecular surface areas, molecular volumes, and melting points.

Halogen...halogen interactions in pressure-frozen ortho- and meta-dichlorobenzene isomers

2007 ◽  
Vol 63 (1) ◽  
pp. 124-131 ◽  
Author(s):  
Maciej Bujak ◽  
Kamil Dziubek ◽  
Andrzej Katrusiak
Keyword(s):  
Intermolecular Interactions ◽  
Room Temperature ◽  
Diamond Anvil Cell ◽  
Crystal Packing ◽  
Molecular Shape ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil ◽  
Steric Hindrances

Isomers 1,2-dichlorobenzene (o-DCB) and 1,3-dichlorobenzene (m-DCB) were high-pressure frozen in-situ in a Merrill–Bassett diamond–anvil cell and their structures determined at room temperature and at 0.18 (5) GPa for o-DCB, and 0.17 (5) GPa for m-DCB by single-crystal X-ray diffraction. The patterns of halogen...halogen intermolecular interactions in these structures can be considered to be the main cohesive forces responsible for the molecular arrangements in these crystals. The molecular packing of dichlorobenzene isomers, including three polymorphs of 1,4-dichlorobenzene (p-DCB), have been compared and relations between their molecular symmetry, packing arrangements, intermolecular interactions and melting points discussed. The topology of the crystal packing in dichlorobenzene isomers results from the interplay of the molecular shape, steric hindrances and intermolecular interactions. The non-planar arrangement of the dichlorobenzene molecules in the crystal structures can be justified by the distributions of the electrostatic potential on molecular surfaces, which determines electrostatic intermolecular interactions.

scholarly journals The solubility and stability of heterocyclic chalcones compared with trans-chalcone

2020 ◽  
Vol 76 (1) ◽  
pp. 13-17
Author(s):  
Stephen G. Sweeting ◽  
Charlie L. Hall ◽  
Jason Potticary ◽  
Natalie E. Pridmore ◽  
Stephen D. Warren ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystals ◽  
Intermolecular Interactions ◽  
Crystal Engineering ◽  
Thiophene Ring ◽  
Melting Points ◽  
Pharmaceutical Applications ◽  
The Future ◽  
Antibacterial And Antifungal

Heterocyclic chalcones are a recently explored subgroup of chalcones that have sparked interest due to their significant antibacterial and antifungal capabilities. Herein, the structure and solubility of two such compounds, (E)-1-(1H-pyrrol-2-yl)-3-(thiophen-2-yl)prop-2-en-1-one and (E)-3-phenyl-1-(1H-pyrrol-2-yl)prop-2-en-1-one, are assessed. Single crystals of (E)-1-(1H-pyrrol-2-yl)-3-(thiophen-2-yl)prop-2-en-1-one were grown, allowing structural comparisons between the heterocyclic chalcones and (2E)-1,3-diphenylprop-2-en-1-one, trivially known as trans-chalcone. The two heterocyclic chalcones were found to be less soluble in all solvents tested and to have higher melting points than trans-chalcone, probably due to their stronger intermolecular interactions arising from the functionalized rings. Interestingly, however, it was found that the addition of the thiophene ring in (E)-1-(1H-pyrrol-2-yl)-3-(thiophen-2-yl)prop-2-en-1-one increased both the melting point and solubility of the sample compared with (E)-3-phenyl-1-(1H-pyrrol-2-yl)prop-2-en-1-one. This observation may be key for the future crystal engineering of heterocyclic chalcones for pharmaceutical applications.

In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

1991 ◽  
Vol 49 ◽  
pp. 660-661
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
High Temperatures ◽  
Image Resolution ◽  
Atomic Processes ◽  
Crystal Surfaces ◽  
Beam Radiation ◽  
Surface Areas ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

Fabrication Technologies and Applications of Graphene-based co-polymeric Nano-composites: its challenges and Future works

2019 ◽  
Vol 09 ◽  
Author(s):  
Pratik Chhapia ◽  
Harshad Patel
Keyword(s):  
Review Paper ◽  
Polymeric Coating ◽  
Nano Composites ◽  
Future Prospects ◽  
Electrical And Optical Properties ◽  
In Situ Techniques ◽  
Surface Areas ◽  
Ink Jet ◽  
Enhanced Conductivity

: Graphene based co-polymeric Nano-composites explored and trending in various applications as ascribing to its enhanced conductivity and controlled modification with wide specific surface areas. With the number of advantages of co-polymeric coating on Graphene or Graphene sheets and their derivatives, Graphene based co-polymeric Nano-composites fabricated by various techniques (deposition, ink jet, electro spinning, spin coating, in-situ techniques, etc.) and different conducting co-polymers show its exceptional chemical, mechanical, electrical and optical properties. Therefore, in the today’s world with greater quantities of various properties of co-polymer with Graphene based Nano-composites with enhanced stability, selectivity and sensitivity have been formed. In this review paper, we have particularly focused on recent advancing in fabrication of different technologies with the help of Graphene based co-polymeric Nano-composites and its various trending and future applications. Finally, on the personal standpoint; the key challenges of Graphene based co-polymeric Nano-composites are mentioned in hope to shed a light on their potential future prospects.

scholarly journals Convenient Access to Functionalized Non-Symmetrical Atropisomeric 4,4′-Bipyridines

Compounds ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 58-74
Author(s):  
Emmanuel Aubert ◽  
Emmanuel Wenger ◽  
Paola Peluso ◽  
Victor Mamane
Keyword(s):  
Solid State ◽  
Intermolecular Interactions ◽  
Medicinal Chemistry ◽  
Crystal Packing ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Halogen Bonds ◽  
Cross Coupling Reactions ◽  
Cyano Groups ◽  
Post Functionalization

Non-symmetrical chiral 4,4′-bipyridines have recently found interest in organocatalysis and medicinal chemistry. In this regard, the development of efficient methods for their synthesis is highly desirable. Herein, a series of non-symmetrical atropisomeric polyhalogenated 4,4′-bipyridines were prepared and further functionalized by using cross-coupling reactions. The desymmetrization step is based on the N-oxidation of one of the two pyridine rings of the 4,4′-bipyridine skeleton. The main advantage of this methodology is the possible post-functionalization of the pyridine N-oxide, allowing selective introduction of chlorine, bromine or cyano groups in 2- and 2′-postions of the chiral atropisomeric 4,4′-bipyridines. The crystal packing in the solid state of some newly prepared derivatives was analyzed and revealed the importance of halogen bonds in intermolecular interactions.

Predictions of Current Attachment at Thermionic Cathode for TIG Arcs

2008 ◽  
Vol 580-582 ◽  
pp. 319-322 ◽  
Author(s):  
Manabu Tanaka ◽  
Kentaro Yamamoto ◽  
Tashiro Shinichi ◽  
John J. Lowke
Keyword(s):  
Melting Point ◽  
Work Function ◽  
Atmospheric Pressure ◽  
The Other ◽  
Numerical Calculations ◽  
Maximum Temperature ◽  
Arc Plasma ◽  
Melting Points ◽  
Thermionic Cathode ◽  
Uniform Current

Study of current attachment at thermionic cathode for TIG arc at atmospheric pressure is attempted from numerical calculations of arc-electrodes unified model. The calculations show that the maximum temperature of arc plasma close to the cathode tip for W-2% ThO2 reaches 19,000 K and it is the highest value in comparison with the other temperatures for W-2% La2O3 and W-2% CeO2, because the current attachment at the cathode tip is constricted by a centralized limitation of liquid area of ThO2 due to its higher melting point. The calculations also show that, in cases of W- 2% La2O3 and W-2% CeO2, the liquid areas of La2O3 and Ce2O3 are widely expanded at the cathode tip due to their lower melting points and then produce uniform current attachments at the cathode. It is concluded that the current attachment at thermionic cathode is strongly dependent on work function, melting point and Richardson constant of emitter materials.

scholarly journals 4-Acetylpiperazinium picrate

2014 ◽  
Vol 70 (6) ◽  
pp. o717-o718 ◽  
Author(s):  
Channappa N. Kavitha ◽  
Manpreet Kaur ◽  
Jerry P. Jasinski ◽  
Hemmige S. Yathirajan
Keyword(s):  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Intermolecular Interactions ◽  
Crystal Packing ◽  
Chair Conformation ◽  
Centroid Distance ◽  
Sheet Structure ◽  
Benzene Rings ◽  
Π Stacking Interaction ◽  
The Mean

In the title salt, C6H13N2O+·C6H2N3O7−(systematic name: 4-acetylpiperazin-1-ium 2,4,6-trinitrophenolate), the piperazin-1-ium ring has a slightly distorted chair conformation. In the picrate anion, the mean planes of the twoo-NO2andp-NO2groups are twisted with respect to the benzene ring by 15.0 (2), 68.9 (4) and 4.4 (3)°, respectively. In the crystal, N—H...O hydrogen bonds are observed, linking the ions into an infinite chain along [010]. In addition, weak cation–anion C—H...O intermolecular interactions and a weak π–π stacking interaction between the benzene rings of the anions, with an inter-centroid distance of 3.771 (8) Å, help to stabilize the crystal packing, giving an overall sheet structure lying parallel to (100). Disorder was modelled for one of the O atoms in one of theo-NO2groups over two sites with an occupancy ratio of 0.57 (6):0.43 (6).

Small Lead and Indium Inclusions in Aluminium

1991 ◽  
Vol 235 ◽  
Author(s):  
E. Johnson ◽  
K. Hjemsted ◽  
B. Schmidt ◽  
K. K. Bourdelle ◽  
A. Johansen ◽  
...  
Keyword(s):  
Melting Point ◽  
Elevated Temperatures ◽  
Supersaturated Solution ◽  
In Situ Tem ◽  
Initial Growth ◽  
Heating And Cooling ◽  
Moiré Fringes ◽  
The Matrix ◽  
Spontaneous Phase

ABSTRACTIon implantation of lead or indium into aluminium results in spontaneous phase separation and formation of lead or indium precipitates. The precipitates grow in topotactical alignment with the matrix, giving TEM images characterized by moiré fringes. The size and density of the precipitates increase with increasing fluence until coalescence begins to occur. Implantations at elevated temperatures lead to formation of larger precipitates with well developed facets. This is particularly significant for implantations above the bulk melting point of the implanted species. Melting and solidification have been followed by in-situ TEM heating and cooling experiments. Superheating up to ∼ 50 K above the bulk melting point has been observed, and the largest inclusions melt first. Melting is associated with only partial loss of facetting of the largest inclusions. Initial growth of the inclusions occurs by trapping of atoms retained in supersaturated solution. Further growth occurs by coalescence of neighbouring inclusions in the liquid phase. Solidification is accompanied by a strong undercooling ∼ 30 K below the bulk melting point, where the smallest inclusions solidify first. Solidification is characterized by spontaneous restoration of the facets and the topotactical alignment.

scholarly journals Better in solubility enhancement : salt or cocrystal?

2019 ◽  
Vol 10 (4) ◽  
pp. 3013-3025
Author(s):  
Iyan Sopyan ◽  
Tazyinul Qoriah Alfauziah ◽  
Dolih Gozali
Keyword(s):  
Melting Point ◽  
Crystal Packing ◽  
Particle Morphology ◽  
Underlying Mechanism ◽  
Solubility Enhancement ◽  
Point Particle ◽  
Ionic Interaction ◽  
Salt Form ◽  
Factors Affecting ◽  
Solubility Profile

Nowadays, most of marketed APIs are in the salt form. But not every single API was ionizable. Thus cocrystallization technique arised to overcome the problem. The aim of this review is to compare the solubility profile of salt and cocrystal. Both salt or cocrystal were used to improve the solubility of APIs and claimed for each other, which is the most effective in solubility enhancement. The salt was formed by ionic interaction, whilst cocrystal formed by hydrogen. Both interactions changed the interaction energy and crystal packing, thus changing the physicochemical properties of APIs. Besides, other factors affecting the solubility of the binary system were melting point, particle morphology, and solubility of coformer. The solubility comparison led to understand the underlying mechanism on solubility enhancement of salt and cocrystal itself.

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