Structures and phase transition of three isomers of 1-phenylindolin-2-one derivatives: 6-chloro-1-phenylindolin-2-one, 4-chloro-1-phenylindolin-2-one and 1-(3-chlorophenyl)indolin-2-one

2018 ◽  
Vol 74 (12) ◽  
pp. 1750-1758
Author(s):  
Bing Wang ◽  
Qi Fang
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Phenyl Ring ◽  
Density Functional ◽  
Room Temperature ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Functional Theory ◽  
Triclinic Space Group ◽  
Space Group

Three 1-phenylindolin-2-one derivatives, namely 6-chloro-1-phenylindolin-2-one (A), 4-chloro-1-phenylindolin-2-one (B) and 1-(3-chlorophenyl)indolin-2-one (C), all C14H10ClNO, have been synthesized and the structures of these compounds at room temperature (A RT, B RT and C RT) and low temperature (A LT, B LT and C LT) have been determined. Crystal A at 295 K (A RT) crystallized in the monoclinic space group P21/c and the phenyl ring of the unique molecule exhibits disorder over two positions. At low temperature, the disorder disappeared and crystal A at 90 K (A LT) crystallized in the triclinic space group P\overline{1} with a doubled unit-cell volume and four molecules in the asymmetric unit. Density functional theory (DFT) calculations revealed a low oscillation barrier (0.24 kcal mol−1) of the phenyl ring of molecule A and the phase transition from the P21/c structure to the P\overline{1} structure can be interpreted in terms of the freezing out of the two conformations at low temperature. Crystal B retains space group P21/c in the temperature range from 100 to 297 K. A kind of obtuse-cell to acute-cell change can be recognized; if the unit cell of B LT at 100 K is set to be a standard obtuse cell [β = 90.341 (2)°] and the cell is kept untransformed in the course of temperature changing, the cell of B RT at 297 K was found to be acute [β = 89.288 (2)°]. The molecules in structure C are packed in layers, with C—H...O hydrogen bonds between neighbouring layers.

scholarly journals Phase transition and structures of the twinned low-temperature phases of (Et4N)[ReS4]

2020 ◽  
Vol 76 (3) ◽  
pp. 231-235
Author(s):  
Eduard Bernhardt ◽  
Regine Herbst-Irmer
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Title Compound ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
Rapid Cooling ◽  
Space Group ◽  
Disordered Structure ◽  
Β Phase ◽  
Α Phase

The title compound, tetraethylammonium tetrathiorhenate, [(C2H5)4N][ReS4], has, at room temperature, a disordered structure in the space group P63 mc (Z = 2, α-phase). A phase transition to the monoclinic space group P21 (Z = 2, γ-phase) at 285 K leads to a pseudo-merohedral twin. The high deviation from the hexagonal metric causes split reflections. However, the different orientations could not be separated, but were integrated using a large integration box. Rapid cooling to 110–170 K produces a metastable β-phase (P63, Z = 18) in addition to the γ-phase. All crystals of the β-phase are contaminated with the γ-phase. Additionally, the crystals of the β-phase are merohedrally twinned. In contrast to the α-phase, the β- and γ-phases do not show disorder.

Le tétrabromomercurate(II) de monométhylammonium

1983 ◽  
Vol 16 (1) ◽  
pp. 142-143 ◽  
Author(s):  
A. Ben Salah
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Bis(monomethylammonium) tetrabromomercurate, (CH3NH3)2HgBr4, 2CH6N+.Hg2+.4Br−, is monoclinic, space group P21/c. Unit-cell dimensions are: a = 7.979(4), b = 13.351(4), c = 11.289(4) Å, β = 96.36(2)°, Z = 4, Dm = 3.25, Dx = 3.24 Mgm−3. The compound undergoes a phase transition at low temperature. The JCPDS Diffraction File No. of this compound is 33-1997.

scholarly journals Structure and pseudosymmetry of cholesterol at 310 K

2002 ◽  
Vol 58 (2) ◽  
pp. 260-264 ◽  
Author(s):  
Leh-Yeh Hsu ◽  
Jeff W. Kampf ◽  
Christer E. Nordman
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Unit Cell ◽  
The Other ◽  
Temperature Phase ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The structure of cholesterol above the (304.8 K) phase transition, previously published in preliminary form [Hsu & Nordman (1983). Science, 220, 604–606], has been fully refined using augmented X-ray data. The crystals are triclinic, space group P1, with (reassigned) cell parameters a = 27.565 (10), b = 38.624 (16), c = 10.748 (4) Å, α = 93.49 (3), β = 90.90 (3), γ = 117.15 (3)°, and V = 10151 (7) Å3. The unit cell contains Z = 16 molecules, of which eight are related to the other eight by unusual twofold rotational pseudosymmetry. The structure is related to the room-temperature phase, with Z = 8, by a rearrangement of some of the molecules, and by a doubling of the a axis.

Z/E-Isomerism of 3-[4-(dimethylamino)phenyl]-2-(2,4,6-tribromophenyl)acrylonitrile: crystal structures and secondary intermolecular interactions

2018 ◽  
Vol 74 (1) ◽  
pp. 69-74
Author(s):  
Renuka Devi Tammisetti ◽  
Ilya V. Kosilkin ◽  
Ilia A. Guzei ◽  
Victor N. Khrustalev ◽  
Larry Dalton ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Crystal Packing ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Triclinic Space Group ◽  
Space Group ◽  
Total Energies ◽  
The Difference

The Z and E isomers of 3-[4-(dimethylamino)phenyl]-2-(2,4,6-tribromophenyl)acrylonitrile, C17H13Br3N2, (1), were obtained simultaneously by a Knoevenagel condensation between 4-(dimethylamino)benzaldehyde and 2-(2,4,6-tribromophenyl)acetonitrile, and were investigated by X-ray diffraction and density functional theory (DFT) quantum-chemical calculations. The (Z)-(1) isomer is monoclinic (space group P21/n, Z′ = 1), whereas the (E)-(1) isomer is triclinic (space group P\overline{1}, Z′ = 2). The two crystallographically-independent molecules of (E)-(1) adopt similar geometries. The corresponding bond lengths and angles in the two isomers of (1) are very similar. The difference in the calculated total energies of isolated molecules of (Z)-(1) and (E)-(1) with DFT-optimized geometries is ∼4.47 kJ mol−1, with the minimum value corresponding to the Z isomer. The crystal structure of (Z)-(1) reveals strong intermolecular nonvalent Br...N [3.100 (2) and 3.216 (3) Å] interactions which link the molecules into layers parallel to (10\overline{1}). In contrast, molecules of (E)-(1) in the crystal are bound to each other by strong nonvalent Br...Br [3.5556 (10) Å] and weak Br...N [3.433 (4) Å] interactions, forming chains propagating along [110]. The crystal packing of (Z)-(1) is denser than that of (E)-(1), implying that the crystal structure realized for (Z)-(1) is more stable than that for (E)-(1).

NQR and Crystal Structure of 4,5-Dichloroimidazole, C3H2N2Cl2

1992 ◽  
Vol 47 (1-2) ◽  
pp. 177-181 ◽  
Author(s):  
Shi-Qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Unit Cell ◽  
Space Group ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Group D

AbstractThe two line 35Cl NQR spectrum of 4,5-dichloroimidazole was measured in the temperature range 77≦ T/K ≦ 389. The temperature dependence of the NQR frequencies conforms with the Bayer model and no phase transition is indicated in the curves v ( 35Cl)= f(T). Also the temperature coefficients of the 35Cl NQR frequencies are "normal". At 77 K the 35Cl NQR frequencies are 37.409 MHz and 36.172 MHz and at 389 K 35.758 MHz and 34.565 MHz. The compound crystallizes at room temperature with the tetragonal space group D44-P41212, Z = 8 molecules per unit cell; at 295 K : a = 684.2(5) pm, c = 2414.0(20) pm. The relations between the crystal structure and the NQR spectrum are discussed.

scholarly journals A High-Pressure Investigation of the Synthetic Analogue of Chalcomenite, CuSeO3∙2H2O

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 643 ◽  
Author(s):  
Javier Gonzalez-Platas ◽  
Placida Rodriguez-Hernandez ◽  
Alfonso Muñoz ◽  
U. R. Rodríguez-Mendoza ◽  
Gwilherm Nénert ◽  
...  
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Pressure Dependence ◽  
Density Functional ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Raman Modes

Synthetic chalcomenite-type cupric selenite CuSeO3∙2H2O has been studied at room temperature under compression up to pressures of 8 GPa by means of single-crystal X-ray diffraction, Raman spectroscopy, and density-functional theory. According to X-ray diffraction, the orthorhombic phase undergoes an isostructural phase transition at 4.0(5) GPa with the thermodynamic character being first-order. This conclusion is supported by Raman spectroscopy studies that have detected the phase transition at 4.5(2) GPa and by the first-principles computing simulations. The structure solution at different pressures has provided information on the change with pressure of unit–cell parameters as well as on the bond and polyhedral compressibility. A Birch–Murnaghan equation of state has been fitted to the unit–cell volume data. We found that chalcomenite is highly compressible with a bulk modulus of 42–49 GPa. The possible mechanism driving changes in the crystal structure is discussed, being the behavior of CuSeO3∙2H2O mainly dominated by the large compressibility of the coordination polyhedron of Cu. On top of that, an assignation of Raman modes is proposed based upon density-functional theory and the pressure dependence of Raman modes discussed. Finally, the pressure dependence of phonon frequencies experimentally determined is also reported.

Synthese von zweikernigen Triazenido- und Pentaazadienidokomplexen des einwertigen Silbers. Kristallstruktur von [Ag(MeOC6H4N3C6H4OM e)]2· 2/3 Py, [Ag(MeOC6H4N5C6H4OMe)]2 und [Ag(EtOC6H4N5C6H4OEt)]2 · Py / Dimeric Triazenido and Pentaazadienido Complexes of Monovalent Silver. Synthesis and Structure of [Ag(MeOC6H4N3C6H4OM e)]2· 2/3 Pyridine, [Ag(MeOC6H4N5C6H4OMe)]2 und [Ag(EtOC6H4N5C6H4OEt)]2 · Pyridine

1989 ◽  
Vol 44 (7) ◽  
pp. 778-785 ◽  
Author(s):  
Edmund Hartmann ◽  
Raimund Schmid ◽  
Joachim Strähle
Keyword(s):  
Unit Cell ◽  
Dinuclear Complexes ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
Bridging Ligand ◽  
Orange Yellow ◽  
Ag Contact ◽  
Saturated Solutions

[Ag(MeOC6H4N3C6H4OMe)]2 (1) is formed in THF from AgNO3 , and the triazenide anion, as obtained from the corresponding triazene and Na. 1 crystallizes from pyridine in the form of orange-yellow , air stable crystals with the com position 1·2/3 C5H5N: space group P 1̅ with a = 1468.0(5), b = 1514.1(6), c - 1316.1(3) pm, a = 113.45(3)°, β = 1 1 4 .8 1 (2 )°, γ = 66.78(3)°, Z - 3. The triazenide ion functions as a bridging ligand forming planar (AgN3)2 heterocycles. The unit cell contains two symmetry-independent dinuclear complexes, one of which is centrosymmetrical. The short Ag -Ag distances of 268.0 and 269.8 pm suggest Ag -Ag bonding. The pentaazadienido complexes Ag(RN5R) with R = p -MeO - C6H4 (2), p -EtO - C6H4 (3), p-Cl -C6H4 (4), p -F -C6H4 (5), are obtained from saturated solutions of the pentaazadiene in conc. NH3 and AgNO3 , as explosive, red precipitates which are stable in air. Crystals of 2 and 3 · C5H5N are obtained from pyridine. 2 crystallizes in the monoclinic space group P21/c: a - 583.7(6), b = 1705.1(9), c = 1489.6(9) pm. β = 96.2(1)°, Z = 2; 3 · C5H5N is triclinic (space group P 1̅) with a = 1160.4(4). b = 1671.0(6), c = 509.0(1) pm. a = 97.51(2)°, β = 97.36(2)°, γ = 81.51(3)°, Z = 1. The complexes 2 and 3 are dinuclear with the pentaazadienide ion as a (N1)-η1,(N5)-η1 bridging ligand in 2 and a (N1)-η1, (N3)-η1 bridging ligand in 3. The bridging mode in 3 results in a short Ag -Ag contact of 283.44 pm. The Ag -N distances range from 210.8 to 215.7 pm in 1 and from 215.0 to 220 pm in (2) and (3).

NTO Polymorphs

1992 ◽  
Vol 296 ◽  
Author(s):  
Kien-yin Lee ◽  
Richard Giloxdi
Keyword(s):  
Crystal Structure ◽  
Cell Density ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
Monoclinic Form ◽  
Network Of Hydrogen Bonds ◽  
Air Bag ◽  
Ray Methods

AbstractNTO is an explosive of current interest. It has been evaluated as an insensitive component to replace RDX in the bomb fill, and as a major ingredient for the auto air bag system. The crystal structure of the β from of NTO has been determined by single-crystal X-ray methods. The unit cell is monoclinic, space group P21/c, with a = 9.326, b = 5.515, c = 9.107 Å, β = 100.77°. There are four molecules in the cell, density 1.878 g/cm3. Infinite extension of H-bonding in two-dimensional sheets occurs in the monoclinic form. Bond lengths and angles all have normal values.Efforts have been made to determine the crystal structure of α-NTO. However, a structure refined only to R = 17% was obtained, probably due to some kind of twinning about the crystal needle axis. The unit cell is triclinic, space group P1, with a = 5.12, b = 10.30, c = 17.9 Å, α = 106.7°, β= 97.7°, γ = 90.2°. There are eight molecules in the cell, density 1.92 g/cm3. Ribbons of NTO molecules formed by a relatively strong network of hydrogen bonds are observed. It was found that α-NTO is the stable, dominating form. A variety of techniques have been chosen to identify the two polymorphs.

Synthese und Kristallstrukturen von N-[ω-(Dimethylammonio)alkyl]- N´,N´,N´´,N´´-tetramethylguanidinium-chlorid-tetraphenylboraten / Synthesis and Crystal Structures of N-[ω-(Dimethylammonio)alkyl]-N´,N´,N´´,N´´- tetramethylguanidinium Chloride Tetraphenylborates

2010 ◽  
Vol 65 (7) ◽  
pp. 907-916 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Falk Lissner ◽  
Thomas Schleid ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Room Temperature ◽  
Chloride Ions ◽  
Monoclinic Space Group ◽  
Temperature Structure ◽  
Space Group ◽  
Temperature Modification

Dicationic N,N´,N´,N´´,N´´-pentasubstituted guanidinium dichlorides 4a, b are obtained from the chloroformamidinium salt 2 and diamines 3a, b. N-[2-(Dimethylammonio)ethyl]-N´,N´,N´´,N´´-tetramethylguanidinium chloride tetraphenylborate (5a) and N-[3-(dimethylammonio)propyl]-N´,N´,N´´,N´´-tetramethylguanidinium chloride tetraphenylborate (5b) were synthesized from 4a, b by anion metathesis with one equivalent of sodium tetraphenylborate. The thermal properties of the salts 5a, b were studied by means of DSC methods, and their crystal structures were determined by single-crystal X-ray diffraction analysis. For 5a a solid-solid phase transition is observed at −156 ◦C to a low-temperature structure. The room-temperature modification (α-5a) crystallizes in the centrosymmetric orthorhombic space group Pbca (a = 13.1844(4), b = 13.8007(4), c = 34.7537(11) A° ).The guanidinium ions are interconnected via chloride ions through bridging N-H· · ·Cl hydrogen bonds, providing isolated units. The tetraphenylborate ions show some dynamic disordering in the crystal structure. The low-temperature modification (β -5a) also crystallizes orthorhombically, but in the non-centrosymmetric space group Pna21 (a = 13.1099(4), b = 69.1810(11), c = 13.5847(5) A° ) and consists of four crystallographically independent cations and anions in the unit cell. Compared with the room-temperature structure, a similar N-H· · ·Cl hydrogen bond pattern is observed in the β -phase, but the tetraphenylborate ions are now completely ordered. 5b crystallizes in the monoclinic space group P21/c (a = 10.8010(3), b = 14.1502(5), c = 20.9867(9) A° , β = 94.322(1)◦). In the crystal structure the guanidinium ions are linked via chloride ions through N-H· · ·Cl hydrogen bonds, but in contrast to 5a two infinite strands are formed along the a axis with the tetraphenylborate ions interspersed between them for charge compensation.

Über die Reaktion von KPPh2 mit Fe(CO)5 und Fe(CO)4CS; Molekülstruktur von [(CO)4FePPh2]- / On the Reaction of KPPh*, with Fe(CO)5 and Fe(CO)4CS; Molecular Structure of [(CO)4FePPh2]-

1996 ◽  
Vol 51 (5) ◽  
pp. 715-721 ◽  
Author(s):  
Wolfgang Petz ◽  
Frank Weller
Keyword(s):  
Molecular Structure ◽  
Elevated Temperature ◽  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Unit Cell ◽  
Radical Mechanism ◽  
Unit Cell Parameters ◽  
Triclinic Space Group ◽  
Space Group ◽  
Cell Parameters

Fe(CO)5 reacts with [PPh2]- in THF at -78 °C to give the adduct [(CO)4FeCOPPh2]- (3) which decomposes at elevated temperature to give [(CO)4FePPh2]- (1), [Fe2(CO)8]2- (2) and (Ph2P)2 probably via a radical mechanism. Attempts to transfer 3 with the electrophiles MeSO3CF3 or Me3SnCl into the corresponding carbenes have failed and Fe(CO)5 along with Ph2PMe and Me3SnPPh2, respectively, are formed. 1 adds one equivalent of CS2 to generate [(CO)4FePPh2CS2]- (4). The [K-18-Krone-6] salt of 1 crystallizes in the triclinic space group P 1̄ with the unit cell parameters a = 929.5(2), b = 1112 .1(2), c = 2017.9(4) pm, α = 100.29(3)°; β = 94.07(3) °; γ = 114.58(3) °. The existence of 3 is established by low temperature 31P NMR spectroscopy.

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