Crystal and molecular structures of two sulfonium ylides: Influence of secondary S...O interactions on the molecular conformation and packing

1991 ◽  
Vol 40 (1) ◽  
pp. 68-73 ◽  
Author(s):  
D. S. Yufit ◽  
Yu. T. Struchkov ◽  
S. I. Kozhushkov ◽  
P. S. Zefirov
Keyword(s):  
Molecular Conformation ◽  
Molecular Structures ◽  
Crystal And Molecular Structures ◽  
Sulfonium Ylides

Crystal and Molecular Structures of the Sulfur-Rich Organic Polysulfanes Heptathiacyclononane (C2H4S7) and Bis(triphenylmethyl)pentaand hexasulfane

1993 ◽  
Vol 48 (7) ◽  
pp. 928-934 ◽  
Author(s):  
Monika Kustos ◽  
Joachim Pickardt ◽  
Jörg Albertsen ◽  
Ralf Steudel
Keyword(s):  
Molecular Conformation ◽  
Accurate Solution ◽  
Molecular Structures ◽  
Torsion Angles ◽  
Crystal And Molecular Structures ◽  
Ring Molecules ◽  
Solvent Molecules ◽  
A Chain ◽  
Single Bonds

Determination of the first structure of a chain-like polysulfane with five sulfur atoms in the chain has been attempted. Bis(triphenylmethyl)pentasulfane forms monoclinic crystals containing disordered solvent molecules preventing an accurate solution of the structure. The (Ph3C)2S5 molecules consist of a helical C–S–S–S–S–S–C backbone (all torsion angles of same sign) and triphenylmethyl groups of normal conformation. The analogous (Ph3C)2S6 forms triclinic crystals; the molecular conformation of the C–S6–C chains is not helical, but the motif of torsion angles is + + – – +. In both compounds the C– S bonds are considerably longer (191 pm) than comparable C–S single bonds as in cyclo-C2H4S7. The latter forms monoclinic crystals consisting of ring molecules of C1 symmetry which can formally be derived from the crown-shaped S8 ring by substituting one sulfur atom by a C2H4 group of approximate C2h symmetry.

Structure–activity studies of β-carbolines. 2. Crystal and molecular structures of N-ethyl-3-carbamoyl-β-carboline

1984 ◽  
Vol 62 (9) ◽  
pp. 1803-1806 ◽  
Author(s):  
Alastair K. S. Muir ◽  
Penelope W. Codding
Keyword(s):  
Molecular Conformation ◽  
Current Model ◽  
Benzodiazepine Receptor ◽  
Molecular Structures ◽  
Side Chain ◽  
Receptor Binding Site ◽  
Crystal And Molecular Structures ◽  
Structure Activity ◽  
Synthetic Ligand ◽  
Packing Arrangement

The crystal and molecular structures of N-ethyl-3-carbamoyl-β-carboline, C14H13N3O, a synthetic ligand of the benzodiazepine receptor are reported. The space group is C2/c with a = 16.220(4), b = 7.728(4), c = 19.623(6) Å, β = 104.16(1)°, Z = 8. The carboxyamide side chain assumes an extended conformation and is almost coplanar with the β-carboline skeleton. The observed molecular conformation is compared to the current model for the receptor binding site. Hydrogen bonding and aromatic ring stacking determine the molecular packing arrangement.

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
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