scholarly journals Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole

2017 ◽  
Vol 73 (11) ◽  
pp. 905-910 ◽  
Author(s):  
Zachary W. Schroeder ◽  
L. K. Hiscock ◽  
Louise Nicole Dawe
Keyword(s):  
Gold Complex ◽  
X Ray ◽  
Benzothiazole Derivatives ◽  
Trigonal Bipyramidal ◽  
Ligand Coordination ◽  
Harsh Conditions ◽  
Chloride Monohydrate ◽  
Insight Into ◽  
Distorted Trigonal Bipyramidal

Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N′-(pyridin-2-yl)thiourea, C13H13N3OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN 3]copper(II) dinitrate, [Cu(C13H11N3OS)2(H2O)](NO3)2, and bis{2-[(5-methoxy-1,3-benzothiazol-2-yl)amino]pyridin-1-ium} dichloridogold(I) chloride monohydrate, (C13H12N3OS)2[AuCl2]Cl·H2O, are reported. The copper complex exhibits a distorted trigonal–bipyramidal geometry, with direct metal-to-benzothiazole-ligand coordination, while the gold complex is a salt containing the protonated uncoordinated benzothiazole, and offers evidence that metal reduction (in this case, AuIII to AuI) is required for the cyclization to proceed. As such, this study provides further mechanistic insight into the role of the metal cations in these transformations.

Crystal structure and lattice energetics of 10-methylacridinium halides

2000 ◽  
Vol 53 (8) ◽  
pp. 627 ◽  
Author(s):  
Piotr Storoniak ◽  
Karol Krzyminski ◽  
Pawel Dokurno ◽  
Antoni Konitz ◽  
Jerzy Blazejowski
Keyword(s):  
Crystal Lattice ◽  
Lattice Energy ◽  
Enthalpies Of Formation ◽  
Triclinic Space Group ◽  
X Ray ◽  
Molecular Arrangement ◽  
Van Der Waals Contacts ◽  
Chloride Monohydrate ◽  
Insight Into

The crystal structures of 10-methylacridinium chloride monohydrate, bromide monohydrate and iodide were determined by X-ray analysis. The compounds crystallize in the triclinic space group, P¯1, with 2 molecules in the unit cell. The molecular arrangement in the crystals revealed that hydrogen bonds (in hydrates) and van der Waals contacts play a significant part in intermolecular interactions. To discover their nature, contributions to the crystal lattice energy arising from electrostatic (the most important since the compounds form ionic crystals), dispersive and repulsive interactions were calculated. Enthalpies of formation of the salts, their stability and susceptibility to decomposition could be predicted from a combination of crystal lattice energies with values of other thermochemical characteristics obtained theoretically or taken from the literature. The role of water in the stabilization of the crystal lattice of the hydrates is also explained. The information gathered has given an insight into the features and behaviour of compounds which can be regarded as models of a large group of aromatic quaternary nitrogen salts.

Crystal and molecular structure of diorganoammonium oxalatotrimethylstannate, [R2NH2][Me3Sn(C2O4)] (R=i-Bu, cyclohexyl)

2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Diffraction Study ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Trans Complex ◽  
A Chain ◽  
Distorted Trigonal Bipyramidal

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.

scholarly journals Crystal structure refinement of magnesium zinc divanadate, MgZnV2O7, from powder X-ray diffraction data

2021 ◽  
Vol 77 (6) ◽  
pp. 588-591
Author(s):  
Stephanie J. Hong ◽  
Jun Li ◽  
Mas A. Subramanian
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Atomic Ratio ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Wyckoff Position ◽  
Distorted Trigonal Bipyramidal

The crystal structure of magnesium zinc divanadate, MgZnV2O7, was determined and refined from laboratory X-ray powder diffraction data. The title compound was synthesized by a solid-state reaction at 1023 K in air. The crystal structure is isotypic with Mn0.6Zn1.4V2O7 (C2/m; Z = 6) and is related to the crystal structure of thortveitite. The asymmetric unit contains two metal sites with statistically distributed magnesium and zinc atoms with the atomic ratio close to 1:1. One (Mg/Zn) metal site (M1) is located on Wyckoff position 8j and the other (M2) on 4h. Three V sites (all on 4i), and eight O (three 8j, four 4i, and one 2b) sites complete the asymmetric unit. The structure is an alternate stacking of V2O7 layers and (Mg/Zn) atom layers along [20\overline{1}]. It is distinct from other related structures in that each V2O7 layer consists of two groups: a V2O7 dimer and a V4O14 tetramer. Mixed-occupied M1 and M2 are coordinated by oxygen atoms in distorted trigonal bipyramidal and octahedral sites, respectively.

Diamond growth on thin Ti wafers via chemical vapor deposition

1995 ◽  
Vol 10 (11) ◽  
pp. 2685-2688 ◽  
Author(s):  
Qijin Chen ◽  
Zhangda Lin
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Titanium Substrate ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Diamond Growth ◽  
X Ray ◽  
Hot Filament ◽  
Insight Into

Diamond film was synthesized on thin Ti wafers (as thin as 40 μm) via hot filament chemical vapor deposition (HFCVD). The hydrogen embrittlement of the titanium substrate and the formation of a thick TiC interlayer were suppressed. A very low pressure (133 Pa) was employed to achieve high-density rapid nucleation and thus to suppress the formation of TiC. Oxygen was added to source gases to lower the growth temperature and therefore to slow down the hydrogenation of the thin Ti substrate. The role of the very low pressure during nucleation is discussed, providing insight into the nucleation mechanism of diamond on a titanium substrate. The as-grown diamond films were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and x-ray analysis.

Organoamido- and Aryloxo-Lanthanoids. XI. Syntheses and Crystal Structures of Nd(Odpp)3, Nd(Odpp)3(thf) and [Nd(Odpp)3(thf)2].2(thf) (Odpp-=2,6-Diphenylphenolate): Variations in Intramolecular π-Ph-Nd Interactions

1995 ◽  
Vol 48 (4) ◽  
pp. 741 ◽  
Author(s):  
GB Deacon ◽  
TC Feng ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Phenyl Group ◽  
Triangular Array ◽  
The Other ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Distorted Trigonal Bipyramidal

The X-ray crystal structure of Nd (Odpp)3 ( Odpp- = 2,6-diphenylphenolate), obtained by sublimation of Nd ( Odpp )3( thf )2 ( thf = tetrahydrofuran ) [triclinic, Pī , a 15.835(5), b 13.499(10), c 10.955(11) Ǻ, α 116.25(7), β 92.87(7), γ 101.66(6)°, V 2031 Ǻ3, Z2, No 5726 'observed' data (I > 3σ(I)) refined to conventional R 0.047 shows a near triangular array of oxygens surrounding neodymium { Nd -O} 2.169 Ǻ, ∑ O- Nd -O 353.2° with additional, intramolecular Nd-η6-Ph chelate interactions { Nd -C} 3.046 Ǻ and Nd-η1-Ph ( Nd -C 2.964(7)Ǻ). There is a pseudotrigonal bipyramidal arrangement of the oxygens, the centroid of the η6-Ph, and the η1-carbon. The complex Nd ( Odpp )3( thf ), obtained by crystallization of Nd ( Odpp )3( thf )2 from toluene (monoclinic, P21/c, a 12.213(4), b 21.447(4), c 17.744Ǻ, β 104.25(2)°, V 4505 Ǻ3, Z 4, R 0.042 for No 8014) also has pseudotrigonal bipyramidal stereochemistry, with a triangular equatorial array of aryl oxide oxygens { Nd -O} 2.193 Ǻ; ∑ O- Nd -O 358.7°, an apical thf oxygen (Nd -O 2.446(3)Ǻ), and an apical intramolecular chelating phenyl group. As the last has three Nd -C contacts (3.094(5), 3.144(5), 3.010(5)Ǻ) significantly shorter than the other three (3.300(5), 3.427(5), 3.377(5)Ǻ), an η3-Ph-Nd interaction seems likely. For [ Nd ( Odpp )3( thf )2].2( thf ), obtained by crystallization from tetrahydrofuran without drying of the crystals, the X-ray structure (monoclinic, P21, a 10.230(2), b 21.919(5), c 13.411(4) Ǻ, β 101.15(2)°, V 2950 A3, Z2, R 0.058 for No 3237) reveals a distorted trigonal bipyramidal arrangement of three aryl oxide oxygens (two equatorial 2.208(9), 2.16(1) Ǻ; one axial 2.203(9) Ǻ) and two thf oxygens (one equatorial 2.44(1) Ǻ; one axial (significantly distant) 2.62(1) Ǻ). The X-ray structure of [La( Odpp )3( thf )2].2( thf ) shows it to be isostructural with the neodymium analogue.

scholarly journals Role of Computational Methods in Going beyond X-ray Crystallography to Explore Protein Structure and Dynamics

2018 ◽  
Vol 19 (11) ◽  
pp. 3401 ◽  
Author(s):  
Ashutosh Srivastava ◽  
Tetsuro Nagai ◽  
Arpita Srivastava ◽  
Osamu Miyashita ◽  
Florence Tama
Keyword(s):  
Protein Dynamics ◽  
Computational Methods ◽  
Protein Structures ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
X Ray ◽  
X Ray Crystallography ◽  
Insight Into

Protein structural biology came a long way since the determination of the first three-dimensional structure of myoglobin about six decades ago. Across this period, X-ray crystallography was the most important experimental method for gaining atomic-resolution insight into protein structures. However, as the role of dynamics gained importance in the function of proteins, the limitations of X-ray crystallography in not being able to capture dynamics came to the forefront. Computational methods proved to be immensely successful in understanding protein dynamics in solution, and they continue to improve in terms of both the scale and the types of systems that can be studied. In this review, we briefly discuss the limitations of X-ray crystallography in studying protein dynamics, and then provide an overview of different computational methods that are instrumental in understanding the dynamics of proteins and biomacromolecular complexes.

Synthesis, Structural Characterization and Luminescence Property of Ring-Like Zinc(II) Complex of N-Paratoluensulfonyl-Glycine Acid and 1,10-Phenanthroline

2011 ◽  
Vol 321 ◽  
pp. 127-130
Author(s):  
Xi Shi Tai
Keyword(s):  
Luminescence Property ◽  
Weak Interactions ◽  
Chelate Ring ◽  
Molar Conductivity ◽  
Tridentate Ligand ◽  
Single Crystal Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Distorted Trigonal Bipyramidal

A novel ring-like zinc (II) complex of N-paratoluensulfonyl-glycine acid and 1,10-phenanthroline was synthesized and characterized by elemental analysis, IR spectrum and molar conductivity. The crystal structure of Zn (II) was determined by X-ray single crystal diffraction. The results show that each zinc (II) atoms is in a distorted trigonal bipyramidal geometry and form 16-membered chelate ring with the tridentate ligand. Intermolecular weak interactions in complex link molecules into a one-dimensional infinite chain supramolecular structure. The luminescence property of the complex was investigated in solid.

Raman and far-infrared spectra of triphenyltin isochalcocyanates and their adducts with O- and N-donor ligands: the crystal and molecular structure of isocyanato-triphenyl (pyridine-N-oxide) tin

1987 ◽  
Vol 65 (3) ◽  
pp. 639-647 ◽  
Author(s):  
Ivor Wharf ◽  
Lars Piehler ◽  
Bruce M. Sailofsky ◽  
Mario Onyszchuk ◽  
Michel G. Simard
Keyword(s):  
Direct Method ◽  
Far Infrared ◽  
Triphenylphosphine Oxide ◽  
Donor Ligands ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Phenyl Rings ◽  
Distorted Trigonal Bipyramidal Coordination ◽  
Far Infrared Spectra ◽  
Distorted Trigonal Bipyramidal

Solid state infrared and Raman data (350–100 cm−1) are reported for Ph3SnNCY (Y = O, S, Se) and their 1:1 adducts with hexamethylphosphoramide (HMPA), pyridine-N-oxide (pyO), 4-picoline-N-oxide (4-picO), triphenylphosphine oxide (Ph3PO), and pyridine (py), as well as for Ph3SnNCSe•L where L = β-pic (β-picoline) or γ-pic (γ-picoline), and assignments are given. The crystal structure of Ph3SnNCO•pyO was determined by single crystal X-ray analysis. The compound crystallizes in space group Pbca with a = 14.443(3), b = 16.676(4), c = 17.523(6) Å (−110 °C); Z = 8. The structure was solved by the direct method and refined by full-matrix least-squares methods to R = 0.024 for 2086 observed reflections. The tin atom has distorted trigonal bipyramidal coordination with the isocyanate group and pyridine-N-oxide at the apices of the bipyramid and phenyl rings in the equatorial positions. Changes in v(Sn—NCY) on adduct formation are correlated with either increased coordination at tin (Y = O) or breaking of strong chalcocyanate bridges with tin remaining five-coordinate (Y = S, Se).

scholarly journals Hypercoordinated Organotin(IV) Compounds Containing ĸ²-C,O- And ĸ²,N- Chelating Ligands: Synthesis, Characterization, and Polymerization Behaviour

2021 ◽  
Author(s):  
Julie Loungxay
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Condensation Polymerization ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Distorted Tetrahedral Geometry ◽  
Trigonal Bipyramidal ◽  
Alternative Approach ◽  
Dimethyl Amine ◽  
Distorted Trigonal Bipyramidal

Rigid homopolystannanes and alternating polystannanes containing a benzyl methoxy ether (C,O) or benzyl dimethyl amine (C,N) ligand were prepared using either a direct approach, lithiation and transmetallation, or an alternative approach, either sequential chlorinations or brominations. X-ray crystallographic studies of 41 and 45 were conducted to find 41 in a distorted tetrahedral geometry with moderate hypercoordinate interaction (Sn-N: 2.917 Å) while 45 in a distorted trigonal bipyramidal with strong hypercoordinate interaction (Sn-N: 2.403 Å). Hydrogenation of 31 and 33 produced 42 and 43 in moderate-to-good yields. Dehydrocoupling polymerization produced modest molecular weight, rigid C,O- (Mw = 3.03 × 10⁴ Da, PDI: 1.4) and C,N- (Mw = 3.10 × 10⁴ Da, PDI: 1.82) homopolymers 56 and 57. Finally, condensation polymerization was attempted to produce low molecular weight (Mw = 1.30 × 10⁴ Da, PDI: 2.0) C,O- alternating polymer 60 and oligomer 61 (Mw = 0.92 × 10⁴ Da, PDI: 2.71).

Cu0.8Mg1.2Si2O6 : a copper-bearing silicate with the low-clinopyroxene structure

2016 ◽  
Vol 80 (2) ◽  
pp. 325-335 ◽  
Author(s):  
Lei Ding ◽  
Céline Darie ◽  
Claire V. Colin ◽  
Pierre Bordet
Keyword(s):  
X Ray Diffraction ◽  
Soft Chemistry ◽  
X Ray ◽  
Cu Content ◽  
Distorted Structure ◽  
Mechanisms Of Formation ◽  
Jahn Teller ◽  
The Stability ◽  
Insight Into

AbstractThe Cu0.8Mg1.2Si2O6 pyroxene has been synthesized using a soft chemistry method. Its crystal structure was determined from powder X-ray diffraction data. Cu0.8Mg1.2Si2O6 crystallizes with the lowclinopyroxene monoclinic structure (space group P21/c). The role of the Jahn-Teller-distorted Cu2+ cation on the stability of this strongly distorted structure is investigated. Cu2+ shows a strong preference for the M2 site, attributed to a better adaptation of its JT-distorted coordination polyhedron to this already distorted and more flexible site. Comparison with previously reported compounds indicates that increasing the Cu content enhances the M2 site distortion, eventually leading to symmetry lowering from orthorhombic Pbca to monoclinic P21/c. These observations bring new insight into the mechanisms of formation and chemical composition of pyroxene minerals in the presence of JT cations.

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