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Titolo:
(R,R)-TARTARIC ACID DIMETHYL DIESTER FROM X-RAY AND AB-INITIO STUDIES- FACTORS INFLUENCING ITS CONFORMATION AND PACKING
Autore:
RYCHLEWSKA U; WARZAJTIS B; HOFFMANN M; RYCHLEWSKI J;
Indirizzi:
ADAM MICKIEWICZ UNIV POZNAN,FAC CHEM,DEPT CRYSTALLOG,UL GRUNWALDZKA 6PL-60780 POZNAN POLAND ADAM MICKIEWICZ UNIV POZNAN,FAC CHEM,DEPT THEORET CHEM PL-60780 POZNAN POLAND POZNAN SUPERCOMP & NETWORKING CTR PL-61713 POZNAN POLAND
Titolo Testata:
Molecules
fascicolo: 7, volume: 2, anno: 1997,
pagine: 106 - 113
SICI:
1420-3049(1997)2:7<106:(ADDFX>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYDROGEN-BOND PATTERNS; RAMAN OPTICAL-ACTIVITY; GRAPH-SET ANALYSIS; TARTARIC ACID; CRYSTALS;
Keywords:
(R,R)-TARTARIC ACID DERIVATIVES; AB-INITIO CALCULATIONS; CRYSTAL STRUCTURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
30
Recensione:
Indirizzi per estratti:
Citazione:
U. Rychlewska et al., "(R,R)-TARTARIC ACID DIMETHYL DIESTER FROM X-RAY AND AB-INITIO STUDIES- FACTORS INFLUENCING ITS CONFORMATION AND PACKING", Molecules, 2(7), 1997, pp. 106-113

Abstract

The conformation of dimethyl (R,R)-tartrate has been analyzed on the basis of the single crystal X-ray diffraction method as well as by ab-initio quantum chemical studies. The results showed that the extended T conformation containing two planar hydroxyester moieties predominates in both ab-initio and X-ray studies. The lowest energy conformer in ab-initio calculations has C-2 symmetry and hydrogen bonds between a hydroxyl group and the nearest carbonyl oxygen. The second in energetical sequence, with an energy difference of only 1.2 kcal/mol, is the asymmetrical conformer, which differs from the lowest energy form by therotation of one of the ester groups by 180 degrees. Intramolecular OH... O hydrogen bonds observed in this rotamer again involve only proximal functional groups. This conformer is present in the crystal structure of the studied compound, although its conformation in the solid state is no longer stabilized by intramolecular hydrogen bonds of the type mentioned above. In the crystal, hydroxyl groups are mostly involved in intermolecular hydrogen bonds and form only a weak intramolecular hydrogen bond with each other. The planar arrangement of the alpha-hydroxyester moieties combined with the extended conformation of the carbon chain seems to be stabilized by the intramolecular hydrogen bondsbetween neighboring functional groups and by the long range dipole-dipole interactions between two pairs of CO and (beta)C-H bonds.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 23/09/20 alle ore 04:33:28