scholarly journals An antitrichomonal drug. 2-(2'-Thenoyl)amino-5-nitrothiazole, C8H5O3N3S2. The crystal and molecular structures of a novel monoclinic system solvated with dimethylformamide.

1987 ◽  
Vol 35 (6) ◽  
pp. 2419-2425 ◽  
Author(s):  
BERNARD VIOSSAT ◽  
NGUYEN-HUY DUNG ◽  
JEAN-CHARLES LANCELOT ◽  
FRANCIS ROBERT ◽  
MAX ROBBA
Keyword(s):  
Molecular Structures ◽  
Monoclinic System ◽  
Crystal And Molecular Structures

scholarly journals Structural Characterization of Two Polymorphs of 1-(4-Methylpyridin-2-yl)thiourea and Two Derived 2-Aminothiazoles

2020 ◽  
Author(s):  
Denise Böck ◽  
Andreas Beuchel ◽  
Richard Goddard ◽  
Peter Imming ◽  
Rüdiger W. Seidel
Keyword(s):  
Crystal Structure ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Hantzsch Reaction ◽  
Orthorhombic Space Group ◽  
Monoclinic System ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Polymorphic Forms ◽  
Hydrogen Bonded

Abstract Two polymorphic forms of 1-(4-methylpyridin-2-yl)thiourea (1) and the crystal and molecular structures of the 2-aminothiazoles N-(4-methylpyridin-2-yl)-4-(pyridin-2-yl)thiazol-2-amine (2) and N-(4-methylpyridin-2-yl)-4-(pyrazin-2-yl)thiazol-2-amine (3), derived from 1 and the respective α-bromoketone via the Hantzsch reaction, are described. Both polymorphic forms 1α (space group P21/c, Z = 4) and 1β (space group P21/n, Z = 8) crystallize in the monoclinic system but exhibit distinctly different intermolecular hydrogen bonding patterns. Compound 2 (orthorhombic, space group Pca21, Z = 8) forms polymeric N–H⋯N hydrogen-bonded zigzag tapes in the polar crystal structure, with a significant twisting between the thiazole and pyridine rings. In contrast, the crystal structure of 3 (monoclinic, space group P21/c, Z = 4) features nearly planar centrosymmetric N–H⋯N hydrogen-bonded dimers, which are laterally joined through long C–H⋯N contacts, affording a π⋯π stacked layered structure. Graphic Abstract Two polymorphs of 1-(4-methylpyridin-2-yl)thiourea and the crystal and molecular structures of two 2-aminothiazoles, derived from 1-(4-methylpyridin-2-yl)thiourea and α-bromoketones via Hantzsch reaction, are reported.

Kristall- und Molekülstrukturen von zwei trans-1.2.4.5-Tetraza-3.6-diphospha-cyclohexan-3.6-disulfiden / Crystal and Molecular Structures of Two trans- 1,2,4,5-Tetraza-3,6-diphospha-cyclohexane-3,6-disulfides

1984 ◽  
Vol 39 (3) ◽  
pp. 269-274 ◽  
Author(s):  
Franz Dirschl ◽  
Heinrich Nöth
Keyword(s):  
Chair Conformation ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
Torsion Angles ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Twist Conformation

The crystal and molecular structures of two trans-1,2,4,5-tetraza-diphospha-3,6-cyclohexane- 3,6-disulfides, 2 and 3, have been determined by X-ray diffraction methods. The 3,6-diphenyl- 1,2,4,5-tetramethyl-derivative 2 crystallizes in the monoclinic system, space group C He. Its P2N 4 heterocycle adopts a twist conformation. In contrast, the hexamethyl derivative 3 is triclinic, space group P1̅, and its ring shows chair conformation. Torsion angles in these two compounds and similar ones reveal less interaction between lone pairs of electrons on adjacent N-atoms in the chair conformation but stronger interaction of those bound to phosphorus. It is suggested that the latter interaction is responsible for the larger N -P -N bond angle (107°) as compared to the smaller one (101°) in the P2N4 rings present in twist conformation.

The crystal and molecular structures of two isostructural complexes: [(H3O•18-crown-6)2(ZnCl4)] and [(H3O•18-crown-6)2(MnCl4)]

1990 ◽  
Vol 68 (6) ◽  
pp. 797-803 ◽  
Author(s):  
Robert Chênevert ◽  
Daniel Chamberland ◽  
Michel Simard ◽  
François Brisse
Keyword(s):  
Crown Ether ◽  
Molecular Structures ◽  
The Other ◽  
Tetrahedral Coordination ◽  
Monoclinic System ◽  
Crystal And Molecular Structures ◽  
Hydronium Ion ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Ether Molecule

New macrocycle polyether 18-crown-6 complexes of stoichiometry [(H3O+•18-crown-6)2(MC42−)] have been synthesized for M = Zn and Mn. The two complexes are isostructural and crystallize in the monoclinic system, space group C2/c. The unit cell dimensions are as follows: a = 16.229(9), b = 11.535(3), c = 20.134(8) Å, β = 97.55(4)° and a = 16.255(6), b = 11.625(3), c = 20.122(8) Å, β = 96.54(3)° for the Zn and Mn complexes respectively. In both crystal structures (final Rw = 0.048 with 1817 reflections for Zn and Rw = 0.074 with 728 reflections for Mn), the crown ether molecule and the H3O+ cation to which it is hydrogen-bonded are disordered over two sites. The MCl42− anions, which have tetrahedral coordination, are on crystallographic twofold axes of rotation. The Mn—Cl and Zn—Cl distances average 2.270 and 2.361 Å respectively. The hydronium cation, H3O+, has pyramidal coordination. Of the two disordered crown ether molecules in the Zn and the Mn complexes, one has a slightly deformed (ttg)6 conformation while the other one may be described as having the distorted (ttg)5(ttc) conformation. These observations are in agreement with the infrared analyses of the complexes. Keywords: 18-crown-6 complexes, hydronium ion, ZnCl42−, MnCl42−, crystal structure.

A Solvent-Dependent and Electrochemically Controlled Self-Assembling/Disassembling System

2003 ◽  
Vol 68 (9) ◽  
pp. 1647-1662 ◽  
Author(s):  
Valeria Amendola ◽  
Massimo Boiocchi ◽  
Yuri Diaz Fernandez ◽  
Carlo Mangano ◽  
Piersandro Pallavicini
Keyword(s):  
Equilibrium Mixture ◽  
Bidentate Ligand ◽  
Molecular Structures ◽  
The Self ◽  
Molar Ratio ◽  
Crystal And Molecular Structures ◽  
Self Assembling ◽  
Irreversible Oxidation ◽  
Irreversible Reduction ◽  
Metal Ligand

The bis-bidentate ligand R,S-1,2-diphenyl-N,N'-bis(2-quinolinemethylidene)ethane-1,2-diamine (ligand 4), containing two (iminomethyl)quinoline moieties separated by a cis-1,2-diphenylethylene spacer, forms stable complexes with both CuI and CuII. With CuII, the monomeric 1:1 complex [CuII(4)]2+ is obtained both in CH3CN and CH2Cl2. With CuI and overall 1:1 metal/ligand molar ratio, an equilibrium mixture is obtained in CH3CN, consisting of [CuI(4)2]+, [CuI2(4)2]2+ and [CuI2(4)(CH3CN)4]2+. The preponderant species is the two-metal one-ligand "open" complex [CuI2(4)(CH3CN)4]2+, in which each Cu+ cation is coordinated in a tetrahedral fashion by one (iminomethyl)quinoline unit and by two CH3CN molecules. Precipitation from the equilibrium mixture yields only crystals of [CuI2(4)(CH3CN)4](ClO4)2·2CH3CN, whose crystal and molecular structures have been determined. On the other hand, in the poorly coordinating CH2Cl2 solvent, only the dimeric helical [CuI2(4)2]2+ complex is obtained, when the overall metal/ligand 1:1 molar ratio is chosen. Addition of large quantities of acetonitrile to solutions of [CuI2(4)2]2+ in dichlorometane results in the formation of [CuI2(4)(CH3CN)4]2+, i.e. in the solvent-driven disassembling of the CuI helicate. While electrochemistry in CH3CN is poorly defined due to the presence of more than one CuI species, cyclic voltammetry experiments carried out in CH2Cl2 revealed a well defined behavior, with irreversible oxidation of [CuI2(4)2]2+ and irreversible reduction of [CuII(4)]2+ taking place at separate potentials (∆E ≈ 700 mV). Irreversibility and separation of the redox events are due to the self-assembling and disassembling processes following the reduction and oxidation, respectively.

Synthesis of Trispirocyclotriphosphazenes with Oxaphosphorine Rings and Their Crystal and Molecular Structures

2021 ◽  
Vol 60 (7) ◽  
pp. 5014-5020
Author(s):  
Yuji Tada ◽  
Atsushi Sunada ◽  
Riki Watanabe ◽  
Makoto Kanazawa ◽  
Keiichiro Utsumi
Keyword(s):  
Molecular Structures ◽  
Crystal And Molecular Structures

Crystal and molecular structures of the complexes of dimethyltin dihalides with dimethyl sulfoxide and dimethylformamide

1978 ◽  
Vol 19 (1) ◽  
pp. 91-98 ◽  
Author(s):  
L. A. Aslanov ◽  
V. M. Ionov ◽  
V. M. Attiya ◽  
A. B. Permin ◽  
V. S. Petrosyan
Keyword(s):  
Dimethyl Sulfoxide ◽  
Molecular Structures ◽  
Crystal And Molecular Structures
Sign in / Sign up

Export Citation Format

Share Document