scholarly journals Tris(ethylenediamine) Cobalt(II) and Manganese(II) Nitrates

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 472
Author(s):  
Miguel Cortijo ◽  
Ángela Valentín-Pérez ◽  
Mathieu Rouzières ◽  
Rodolphe Clérac ◽  
Patrick Rosa ◽  
...  
Keyword(s):  
Phase Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
Orbital Contribution ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Heat Capacity Measurements ◽  
Reversible Phase

Octahedral tris(ethylenediamine) coordination complexes demonstrate helicoidal chirality, due to the arrangement of the ligands around the metal core. The enantiomers of the nitrate salts [Ni(en)3](NO3)2 and [Zn(en)3](NO3)2 spontaneously resolve to form a mixture of conglomerate crystals, which present a reversible phase transition from space group P6322 to enantiomorphic P6522 or P6122, with the latter depending on the handedness of the enantiomer. We report here the synthesis and characterization of [Mn(en)3](NO3)2 and [Co(en)3](NO3)2, which are isostructural to the Zn(II) and Ni(II) derivatives. The Mn(II) analogue undergoes the same phase transition centered at 150(2) K, as determined by single-crystal X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry. The Co(II) derivative does not demonstrate a phase transition down to 2 K, as evidenced by powder X-ray diffraction and heat capacity measurements. The phase transition does not impact the magnetic properties of the Ni(II) and Mn(II) analogues; these high spin compounds display Curie behavior that is consistent with S = 1 and 5/2, respectively, down to 20 K, while the temperature-dependent magnetic moment for the Co(II) compound reveals a significant orbital contribution.

Phase Transition and Thermochromism of the Hybrid (C12H25NH3)2FeCl4

2006 ◽  
Vol 111 ◽  
pp. 55-58
Author(s):  
L.L. Guo ◽  
Y.D. Dai ◽  
H.X. Liu ◽  
Shi Xi Ouyang
Keyword(s):  
Phase Transition ◽  
Structural Changes ◽  
Energy Transition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Gravimetry ◽  
Reversible Phase Transition ◽  
Rotational Motions ◽  
Xrd Patterns ◽  
Reversible Phase

This paper focuses on the structural change and the thermochromism of the phase transition of the hybrid (C12H25NH3)2FeCl4. The temperature and the structures of the phase transition is investigated by a thermal gravimetry (TG) and differential scanning calorimetry (DSC), an infrared spectra (IR) and X-ray diffraction (XRD) patterns. The UV adsorption spectra account for the thermochromism. The results suggest that the reversible phase transition arises from the structural changes of the organic chains. The thermochromism is presumably due to the electrons redistribution on the levels and to the energy transition to translational and rotational motions of the organic chains.

scholarly journals Reversible phase transition in laser-shocked 3Y-TZP ceramics observed via nanosecond time-resolved x-ray diffraction

2012 ◽  
Vol 111 (5) ◽  
pp. 053526 ◽  
Author(s):  
Jianbo Hu ◽  
Kouhei Ichiyanagi ◽  
Hiroshi Takahashi ◽  
Hiroaki Koguchi ◽  
Takeaki Akasaka ◽  
...  
Keyword(s):  
Phase Transition ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Reversible Phase

Die quaternären Systeme ZnAl2S4-ZnGa2S4, ZnAl2S4-CdAl2S4 und ZnAl2S4-ZnAl2Se4. Röntgenographische und schwingungsspektroskopisehe Untersuchungen / Investigation of the Quaternary Systems ZnAl2S4-ZnGa2S4, ZnAl2S4-CdAl2S4 and ZnAl2S4-ZnAl2Se4 by X-Ray Diffraction and Vibrational Spectroscopy

1983 ◽  
Vol 38 (3) ◽  
pp. 311-316 ◽  
Author(s):  
H. Haeuseler ◽  
A. Cansiz
Keyword(s):  
Phase Transition ◽  
Vibrational Spectroscopy ◽  
Solid Solutions ◽  
Homogeneity Range ◽  
Binary Systems ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Reversible Phase ◽  
Fir Spectra

The quasi-binary systems Zn1-xCdxAl2S4, ZnAl2(1-x)Ga2xS4 and ZnAl2S4(1-x)Se4x have been investigated by X-ray diffraction and vibrational spectroscopy. In the spinel ZnAI2S4 up to 20% of Zn can be replaced by Cd. In the two other systems, ZnAl2S4 has no detectable homogeneity range. The thiogallate phases have much broader ranges of homogeneity. The compositions of the compounds at the phase boundary of the thiogallate phase are Zn0.4Cd0.6Al2S4, ZnGa0.4Al1.6S4, and ZnAl2S2.8Se1.2. At approximately 950 °C ZnAl2Se4 undergoes a reversible phase transition to a wurtzite-type structure. This phase transition is also observed for the solid solutions ZnAl2S4(1-x)Se4x; with 1.0 > x > 0.3. The FIR spectra are discussed.

scholarly journals A Reversible Phase Transition of 2D Coordination Layers by B–H∙∙∙Cu(II) Interactions in a Coordination Polymer

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3204 ◽  
Author(s):  
Lei Gan ◽  
Pol G. Fonquernie ◽  
Mark E. Light ◽  
Gantulga Norjmaa ◽  
Gregori Ujaque ◽  
...  
Keyword(s):  
Phase Transition ◽  
Coordination Polymer ◽  
Thermal Activation ◽  
Bet Surface Area ◽  
Co2 Uptake ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Open Metal Sites ◽  
Reversible Phase

Materials that combine flexibility and open metal sites are crucial for myriad applications. In this article, we report a 2D coordination polymer (CP) assembled from CuII ions and a flexible meta-carborane-based linker [Cu2(L1)2(Solv)2]•xSolv (1-DMA, 1-DMF, and 1-MeOH; L1: 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane). 1-DMF undergoes an unusual example of reversible phase transition on solvent treatment (i.e., MeOH and CH2Cl2). Solvent exchange, followed by thermal activation provided a new porous phase that exhibits an estimated Brunauer-Emmett-Teller (BET) surface area of 301 m2 g−1 and is capable of a CO2 uptake of 41 cm3 g−1. The transformation is reversible and 1-DMF is reformed on addition of DMF to the porous phase. We provide evidence for the reversible process being the result of the formation/cleavage of weak but attractive B–H∙∙∙Cu interactions by a combination of single-crystal (SCXRD), powder (PXRD) X-ray diffraction, Raman spectroscopy, and DFT calculations.

Erratum: “Reversible phase transition in laser-shocked 3Y-TZP ceramics observed via nanosecond time-resolved x-ray diffraction” [J. Appl. Phys. 111, 053526 (2012)]

2013 ◽  
Vol 113 (3) ◽  
pp. 039901 ◽  
Author(s):  
Jianbo Hu ◽  
Kouhei Ichiyanagi ◽  
Hiroshi Takahashi ◽  
Hiroaki Koguchi ◽  
Takeaki Akasaka ◽  
...  
Keyword(s):  
Phase Transition ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Reversible Phase

Morphological Transitions in Fluorinated and Non-Fluorinated Parylenes

1999 ◽  
Vol 565 ◽  
Author(s):  
Michael Morgen ◽  
Jie-Hua Zhao ◽  
Seung-Hyun Rhee ◽  
E. Todd Ryant ◽  
Huei-Min Ho ◽  
...  
Keyword(s):  
Significant Shift ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Morphological Transitions ◽  
Crystallinity Changes ◽  
Chain Contraction ◽  
Reversible Phase

AbstractA study of temperature-induced crystallinity changes in fluorinated and nonfluorinated parylene thin films using differential scanning calorimetry, thermal stress and wide angle x-ray diffraction measurements is presented. The nonfluorinated parylene (ppx-N) is shown to undergo two phase transitions between 200°C and 300°C. Both transitions show at least some degree of reversibility. The high temperature (β1 -β2) transition is accompanied by a sudden shift in stress, which is attributed to a contraction of the polymers chains. A single, reversible phase transition, occurring between 360°C and 400°C, is observed for fluorinated parylene (ppx-F). This transition is likewise marked by a significant shift in stress, and is apparently due to a similar chain contraction.

Solid-state transformations in the β-form of chlorpropamide on cooling to 100 K

2011 ◽  
Vol 67 (2) ◽  
pp. 163-176 ◽  
Author(s):  
Tatiana N. Drebushchak ◽  
Valeri A. Drebushchak ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Single Crystal ◽  
Second Phase ◽  
Organic Crystals ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Reversible Phase ◽  
Alkyl Tail

A single-crystal X-ray diffraction study of the effect of cooling down to 100 K on the β-form of chlorpropamide, 4-chloro-N-(propylaminocarbonyl)benzenesulfonamide, has revealed reversible phase transitions at ∼ 257 K and between 150 and 125 K: β (Pbcn, Z′ = 1)  βII (P2/c, Z′ = 2)  βIII (P2/n, a′ = 2a, Z′ = 4); the sequence corresponds to cooling. Despite changes in the space group and number of symmetry-independent molecules, the volume per molecule changes continuously in the temperature range 100–300 K. The phase transition at ∼ 257 K is accompanied by non-merohedral twinning, which is preserved on further cooling and through the second phase transition, but the original single crystal does not crack. DSC (differential scanning calorimetry) and X-ray powder diffraction investigations confirm the phase transitions. Twinning disappears on heating as the reverse transformations take place. The second phase transition is related to a change in conformation of the alkyl tail from trans to gauche in 1/4 of the molecules, regularly distributed in the space. Possible reasons for the increase in Z′ upon cooling are discussed in comparison to other reported examples of processes (crystallization, phase transitions) in which organic crystals with Z′ > 1 have been formed. Implications for pharmaceutical applications are discussed.

Phase Transition of Na3As under Pressure

1990 ◽  
Vol 45 (10) ◽  
pp. 1388-1392 ◽  
Author(s):  
Heinz Jürgen Beister ◽  
Karl Syassen ◽  
Jürgen Klein
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Structural Properties ◽  
Pressure Range ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Equation Of States ◽  
Reversible Phase Transition ◽  
Reversible Phase

We have investigated the high pressure behaviour of Na3As by powder X-ray diffraction. At 3.6 GPa the material undergoes a reversible phase transition from the Na3As structure (P 63/mmc, a = 487.4(8) pm, c = 851.5(20) pm, Z = 2, at 3.6 GPa) to the Li3Bi structure type (Fm 3̅ m, a = 683.5(15) pm, Z = 4, at 3.6 GaP). The equation of states is given for the pressure range up to 26 GPa. Results are discussed with respect to structural properties of related A3IBV-compounds

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

Temperature-Dependent Solid-state Luminescence and Reversible Phase Transition of (n-Bu4N)[Au(SC6H3-3,5-Me2)2]

2003 ◽  
Vol 32 (11) ◽  
pp. 1002-1003 ◽  
Author(s):  
Seiji Watase ◽  
Takayuki Kitamura ◽  
Nobuko Kanehisa ◽  
Masami Nakamoto ◽  
Yasushi Kai ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solid State ◽  
Temperature Dependent ◽  
Reversible Phase Transition ◽  
Reversible Phase ◽  
State Luminescence
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