Thermally induced structural transformations of a series of palladium(II) complexes with N-heteroaromatic bidentate hydrazone ligands

2014 ◽  
Vol 592 ◽  
pp. 23-30 ◽  
Author(s):  
Nebojša Begović ◽  
Vladimir A. Blagojević ◽  
Sanja B. Ostojić ◽  
Darko M. Micić ◽  
Nenad Filipović ◽  
...  
Keyword(s):  
Structural Transformations ◽  
Thermally Induced ◽  
Hydrazone Ligands

Solid-state dynamics and single-crystal to single-crystal structural transformations in octakis(3-chloropropyl)octasilsesquioxane and octavinyloctasilsesquioxane

2017 ◽  
Vol 19 (40) ◽  
pp. 27516-27529 ◽  
Author(s):  
A. Kowalewska ◽  
M. Nowacka ◽  
M. Włodarska ◽  
B. Zgardzińska ◽  
R. Zaleski ◽  
...  
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Structural Transformations ◽  
Crystal Lattices ◽  
Thermally Induced ◽  
Crystal Structural

Thermally induced formation of symmetric crystal lattices in functional POSS proceeds via different mechanisms and results in unique reversible phenomena.

scholarly journals Thermal Reactivity in Metal Organic Materials (MOMs): From Single-Crystal-to-Single-Crystal Reactions and Beyond

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4088
Author(s):  
Javier Martí-Rujas
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Organic Materials ◽  
Structural Transformations ◽  
Atomic Motion ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Thermal Reactivity ◽  
Metal Organic

Thermal treatment is important in the solid-state chemistry of metal organic materials (MOMs) because it can create unexpected new structures with unique properties and applications that otherwise in the solution state are very difficult or impossible to achieve. Additionally, high-temperature solid-state reactivity provide insights to better understand chemical processes taking place in the solid-state. This review article describes relevant thermally induced solid-state reactions in metal organic materials, which include metal organic frameworks (MOFs)/coordination polymers (CPs), and second coordination sphere adducts (SSCs). High temperature solid-state reactivity can occur in a single-crystal-to-single crystal manner (SCSC) usually for cases where there is small atomic motion, allowing full structural characterization by single crystal X-ray diffraction (SC-XRD) analysis. However, for the cases in which the structural transformations are severe, often the crystallinity of the metal-organic material is damaged, and this happens in a crystal-to-polycrystalline manner. For such cases, in the absence of suitable single crystals, structural characterization has to be carried out using ab initio powder X-ray diffraction analysis or pair distribution function (PDF) analysis when the product is amorphous. In this article, relevant thermally induced SCSC reactions and crystal-to-polycrystalline reactions in MOMs that involve significant structural transformations as a result of the molecular/atomic motion are described. Thermal reactivity focusing on cleavage and formation of coordination and covalent bonds, crystalline-to-amorphous-to-crystalline transformations, host–guest behavior and dehydrochlorination reactions in MOFs and SSCs will be discussed.

Thermally Induced Structural Transformations of Fe40Ni40P14B6 Amorphous Alloy

2015 ◽  
Vol 47 (1) ◽  
pp. 260-267 ◽  
Author(s):  
Milica M. Vasić ◽  
Pavla Roupcová ◽  
Naděžda Pizúrová ◽  
Sanja Stevanović ◽  
Vladimir A. Blagojević ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Structural Transformations ◽  
Thermally Induced

scholarly journals Effect of cooling rate on structural transformations in Ti-Al-V nanoalloy: molecular dynamics study

2021 ◽  
Vol 2052 (1) ◽  
pp. 012038
Author(s):  
N Yu Sdobnyakov ◽  
V M Samsonov ◽  
V S Myasnichenko ◽  
P M Ershov ◽  
A N Bazulev ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Size Effect ◽  
Cooling Rate ◽  
Tight Binding ◽  
Structural Transformations ◽  
Rate Effect ◽  
Binding Potential ◽  
Cooling Rates ◽  
Thermally Induced ◽  
Local Structures

Abstract Using the isothermal molecular dynamics and the tight-binding potential, crystallization of Ti6Al4V nanodroplets was simulated. The objects of the research consisted of 2869 atoms, including 172 Al atoms and 115 V ones. The OVITO program was employed to recognize local structures and nanophases arisen in the course of cooling nanoalloy with the cooling rates of 0.1 and 0.4 K/ps. We have found that the cooling rate effect on the structure of the Ti6Al4V nanoalloy and the thermally induced structural transformations is much more pronounced than the size effect.

scholarly journals Thermally Induced Structural Transformations on Polymorphous Silicon

2005 ◽  
Vol 20 (9) ◽  
pp. 2562-2567 ◽  
Author(s):  
Chandana Rath ◽  
J. Farjas ◽  
P. Roura ◽  
F. Kail ◽  
P. Roca i Cabarrocas ◽  
...  
Keyword(s):  
Evolved Gas Analysis ◽  
Structural Transformations ◽  
Gas Analysis ◽  
Evolved Gas ◽  
Thermally Induced ◽  
Complementary Technique ◽  
Si Nanocrystals ◽  
Si Nanoparticles ◽  
Amorphous Si ◽  
Hydrogenated Amorphous

Polymorphous Si is a nanostructured form of hydrogenated amorphous Si that contains a small fraction of Si nanocrystals or clusters. Its thermally induced transformations such as relaxation, dehydrogenation, and crystallization have been studied by calorimetry and evolved gas analysis as a complementary technique. The observed behavior has been compared to that of conventional hydrogenated amorphous Si and amorphous Si nanoparticles. In the temperature range of our experiments (650–700 °C), crystallization takes place at almost the same temperature in polymorphous and in amorphous Si. In contrast, dehydrogenation processes reflect the presence of different hydrogen states. The calorimetry and evolved gas analysis thermograms clearly show that polymorphous Si shares hydrogen states of both amorphous Si and Si nanoparticles. Finally, the total energy of the main Si–H group present in polymorphous Si has been quantified.

scholarly journals Hydrogen-Bonding Assembly of Coordination Polymers Showing Reversible Dynamic Solid-State Structural Transformations

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 115
Author(s):  
Hitoshi Kumagai ◽  
Sadahiro Yagishita ◽  
Ken Kanazashi ◽  
Mariko Ishii ◽  
Shinya Hayami ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Structural Transformation ◽  
Coordination Polymers ◽  
Chain Structure ◽  
Structural Transformations ◽  
The Other ◽  
Ambient Conditions ◽  
Thermally Induced ◽  
Dehydration Processes

We herein report the synthesis, single-crystal structures of coordination polymers, and structural transformations of complexes employing 1,4,5,6-tetrahydro-5,6-dioxo-2,3-pyrazinedicarbonitrile (tdpd2−) and pyrazine (pyz) as bridging ligands. {[M(H2O)4(pyz)][M(tdpd)2(pyz)]·6(H2O)}n, [1·10H2O and 2·10H2O where M = Co (1) and Zn (2)], consists of two types of crystallographically independent one-dimensional (1D) structures packed together. One motif, [M(tdpd)2(pyz)]2− (A), is an anionic infinite pyz bridged 1D array with chelating tdpd2− ligands, and the other motif is a cationic chain, [M(H2O)4(pyz)]2+ (B), which is decorated with four terminal water molecules. The 1D arrays (A) and (B) are arranged in parallel by multi-point hydrogen-bonding interactions in an alternate (A)(B)(A)(B) sequence extending along the c-axis. Both compounds exhibit structural transformations driven by thermal dehydration processes around 350 K to give partially dehydrated forms, 1·2H2O and 2·2H2O. The structural determination of the partially dehydrated form, 2·2H2O, reveals a solid-state structural transformation from a 1D chain structure to a two-dimensional (2D) coordination sheet structure, [Zn2(tdpd)2(H2O)2(pyz)]n (2·2H2O). Further heating to 500 K yields the anhydrous form 2. While the virgin samples of 1·10H2O and 2·10H2O crystallize in different crystal systems, powder X-ray diffraction (PXRD) measurements of the dehydrated forms, 1·2H2O and 2·2H2O, are indicative of the same structure. The structural transformation is irreversible for 1·10H2O at ambient conditions. On the other hand, compound 2·10H2O shows a reversible structural change. The solid-state structural transformation for 1·10H2O was also confirmed by monitoring in-situ magnetic susceptibility, which is consistent with other thermally-induced measurements.

scholarly journals In situ electron microscopy study of structural transformations in 2D CoSe2

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Dnyaneshwar S. Gavhane ◽  
Heleen van Gog ◽  
Balu Thombare ◽  
Gaurav Lole ◽  
L. Christiaan Post ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Elevated Temperatures ◽  
2D Materials ◽  
Microscopy Study ◽  
Structural Transformations ◽  
Electron Microscopy Study ◽  
Thermally Induced ◽  
Transmission Electron ◽  
Transformation Processes

AbstractThermally induced structural transformation of 2D materials opens unique avenues for generating other 2D materials by physical methods. Imaging these transitions in real time provides insight into synthesis routes and property tuning. We have used in situ transmission electron microscopy (TEM) to follow thermally induced structural transformations in layered CoSe2. Three transformation processes are observed: orthorhombic to cubic-CoSe2, cubic-CoSe2 to hexagonal-CoSe, and hexagonal to tetragonal-CoSe. In particular, the unit-cell-thick orthorhombic structure of CoSe2 transforms into cubic-CoSe2 via rearrangement of lattice atoms. Cubic-CoSe2 transforms to hexagonal-CoSe at elevated temperatures through the removal of chalcogen atoms. All nanosheets transform to basal-plane-oriented hexagonal 2D CoSe. Finally, the hexagonal to tetragonal transformation in CoSe is a rapid process wherein the layered morphology of hexagonal-CoSe is broken and islands of tetragonal-CoSe are formed. Our results provide nanoscopic insights into the transformation processes of 2D CoSe2 which can be used to generate these intriguing 2D materials and to tune their properties by modifying their structures for electro-catalytic and electronic applications.

Thermal Stability of SiHn Configurations in Fz Silicon Single Crystals

1992 ◽  
Vol 262 ◽  
Author(s):  
Masami Kouketsu ◽  
Seiichi Isomae
Keyword(s):  
Thermal Stability ◽  
Single Crystals ◽  
Absorption Spectroscopy ◽  
Infrared Absorption ◽  
Structural Transformations ◽  
Infrared Absorption Spectroscopy ◽  
Thermally Induced ◽  
Silicon Lattice ◽  
Silicon Crystals ◽  
Thermal Stability Of

ABSTRACTThermal stability of SiHn (n=1∼4) configurations in FZ silicon crystals grown in Ar/H2 has been investigated by means of infrared absorption spectroscopy. Infrared absorption peaks at 2210, 2192, 2123 and 1946 cm−1, which are due to SiH4, SiH3, SiH2 and SiH units in silicon lattice, has been observed. It is found that the concentration of SiH4 and SiH increase with the decrease in SiH2 and SiH3 concentration at 500°C, and vice versa at 600°C. Annealing results suggest thermally induced structural transformations of SiHn configurations. We propose a model of the transformations through the cleavage of adjacent Si-H bonds to form a Si-Si bond and a H2 molecule, as well as the reaction of a H2 molecule with a Si-Si bond.

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