Examination of the effect of structural variation on the N-glycosidic torsion (ΦN) among N-(β-d-glycopyranosyl)acetamido and propionamido derivatives of monosaccharides based on crystallography and quantum chemical calculations

2009 ◽  
Vol 344 (3) ◽  
pp. 355-361 ◽  
Author(s):  
Mohamed Mohamed Naseer Ali ◽  
Udayanath Aich ◽  
Serge Pérez ◽  
Anne Imberty ◽  
Duraikkannu Loganathan
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Variation ◽  
Derivatives Of

scholarly journals Synthesis and Structure of Methylsulfanyl Derivatives of Nickel Bis(Dicarbollide)

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4449 ◽  
Author(s):  
Sergey A. Anufriev ◽  
Kyrill Yu. Suponitsky ◽  
Oleg A. Filippov ◽  
Igor B. Sivaev
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
X Ray Diffraction ◽  
Gauche Conformation ◽  
X Ray ◽  
Derivatives Of ◽  
Transoid Conformation

Symmetrically and unsymmetrically substituted methylsulfanyl derivatives of nickel(III) bis(dicarbollide) (Bu4N)[8,8′-(MeS)2-3,3′-Ni(1,2-C2B9H10)2], (Bu4N)[4,4′-(MeS)2-3,3′-Ni(1,2-C2B9H10)2], and (Bu4N)[4,7′-(MeS)2-3,3′-Ni(1,2-C2B9H10)2] were synthesized, starting from [Ni(acac)2]3 and the corresponding methylsulfanyl derivatives of nido-carborane (Bu4N)[10-MeS-7,8-C2B9H11] and (Bu4N)[10-MeS-7,8-C2B9H11]. Structures of the synthesized metallacarboranes were studied by single-crystal X-ray diffraction and quantum chemical calculations. The symmetrically substituted 8,8′-isomer adopts transoid conformation stabilized by two pairs of intramolecular C–H···S hydrogen bonds between the dicarbollide ligands. The unsymmetrically substituted 4,7′-isomer adopts gauche conformation, which is stabilized by two nonequivalent C–H···S hydrogen bonds and one short chalcogen B–H···S bond (2.53 Å, −1.4 kcal/mol). The gauche conformation was found to be also preferred for the 4,7′-isomer.

Sterically Crowded Heterocycles. VIII. Preparative Photoisomerization of Some Imidazo[1,2-a]pyridines

1996 ◽  
Vol 61 (10) ◽  
pp. 1473-1488 ◽  
Author(s):  
Richard Kubík ◽  
Stanislav Böhm ◽  
Jan Čejka ◽  
Vladimír Havlíček ◽  
Tomáš Strnad ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Mass Spectra ◽  
X Ray ◽  
Uv Illumination ◽  
Derivatives Of ◽  
Semiempirical Quantum Chemical Calculations

UV-Illumination of (Z)-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)-1,3-diphenylprop-2-en-1-one (1a) or its 6-methyl and 6-iodo derivatives 1c and 1g resulted in minor (E)-isomers 2a, 2c, and 2g and prevailing (E,Z)-mixtures of N-(pyridin-2-yl)-[(3,5-diphenylfuran-2-yl)phenylmethylidene]amines 3a, 3c, and 3g while only corresponding furanoic derivatives 3b and 3d-3f were obtained from 5-methyl (1b), 7-methyl (1d), 8-methyl (1e), and 5-phenyl (1f) derivatives of the (Z)-ketone 1a. VIS-Illumination of (Z)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]benzo[I]quinolin-3-yl)prop-2-en-1-one (4) led to N-(benzo[h]quinolin-2-yl)-[(3,5-diphenylfuran-2-yl)phenylmethylidene]amine (5). Photoisomers 2a, 2c, 2g, 3a-3g, and 5 were isolated and the molecular structure of 3c was X-ray determined. Mechanism of the photoisomerization is discussed using semiempirical quantum chemical calculations and compared with mass spectra of compounds 1a, 2a, 3a, 1g, 2g, and 3g.

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