Dramatic differences in the conformational equilibria of chalcogen-bridged compounds: the case of diallyl ether versus diallyl sulfide

2022 ◽  
Author(s):  
Tamanna Poonia ◽  
Weslley G. D. P. Silva ◽  
Jennifer van Wijngaarden
Keyword(s):  
Quantum Mechanical ◽  
Rotational Spectroscopy ◽  
Quantum Mechanical Calculations ◽  
Diallyl Sulfide ◽  
Conformational Equilibria ◽  
Diallyl Ether ◽  
Significant Change

Rotational spectroscopy and quantum mechanical calculations reveal a significant change in conformational landscapes when oxygen is substituted with sulfur: observation of features from nine conformers of diallylether versus one of the sulfide.

Crystal Forms of Semisynthetic Ergot Alkaloid Terguride

2002 ◽  
Vol 67 (4) ◽  
pp. 479-489 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Ladislav Cvak ◽  
Alexandr Jegorov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ergot Alkaloid ◽  
Simplified Model ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
Crystal Forms ◽  
X Ray ◽  
Independent Molecules

Two new structures of semisynthetic ergot alkaloid terguride created by unusual number of symmetry-independent molecules were determined by X-ray diffraction methods at 150 K. Form A (monoclinic, P212121, Z = 12) contains three symmetry-independent terguride molecules and two molecules of water in the asymmetric part of the unit cell. The form CA (monoclinic, P21, Z = 8) is an anhydrate remarkable by the presence of four symmetry-independent molecules in the crystal structure. Conformations of twelve symmetry-independent molecules that were found in four already described terguride structures are compared with torsion angles obtained by ab initio quantum-mechanical calculations for the simplified model of N-cyclohexyl-N'-diethylurea.

Chemical accuracy from ‘Coulomb hole’ extrapolated molecular quantum-mechanical calculations

2001 ◽  
Vol 567-568 ◽  
pp. 375-384 ◽  
Author(s):  
K.L Bak ◽  
A Halkier ◽  
P Jørgensen ◽  
J Olsen ◽  
T Helgaker ◽  
...  
Keyword(s):  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Coulomb Hole
Sign in / Sign up

Export Citation Format

Share Document