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Titolo:
Chiral recognition in salts of trans-1,2-diaminocyclohexane and optically active tartaric acids: crystal structure of 1 : 2 salt of (S,S)-diaminocyclohexane with (R,R)-tartaric acid.
Autore:
Rychlewska, U;
Indirizzi:
Adam Mickiewicz Univ, Fac Chem, PL-60780 Poznan, Poland Adam Mickiewicz Univ Poznan Poland PL-60780 hem, PL-60780 Poznan, Poland
Titolo Testata:
JOURNAL OF MOLECULAR STRUCTURE
, volume: 474, anno: 1999,
pagine: 235 - 243
SICI:
0022-2860(19990101)474:<235:CRISOT>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR RECOGNITION;
Keywords:
chiral recognition; natural tartaric acid in its three ionisation states; tartaric acid diaminocyclohexane superstructure; three-dimensional hydrogen bonding; mode of acid/amine self assembly;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
9
Recensione:
Indirizzi per estratti:
Indirizzo: Rychlewska, U Adam Mickiewicz Univ, Fac Chem, Grunwaldzka 6, PL-60780 Poznan, Poland Adam Mickiewicz Univ Grunwaldzka 6 Poznan Poland PL-60780 d
Citazione:
U. Rychlewska, "Chiral recognition in salts of trans-1,2-diaminocyclohexane and optically active tartaric acids: crystal structure of 1 : 2 salt of (S,S)-diaminocyclohexane with (R,R)-tartaric acid.", J MOL STRUC, 474, 1999, pp. 235-243

Abstract

X-ray results for the highly organised superstructure (space group P6(5)22) of the 1:2 salt of (1S,2S)-diaminocyclohexane with (R,R)-tartaric acid (1) are compared with the previously reported [1] crystal structures of two diastereomeric 1:1 salts of (R,R)-diaminocyclohexane with (R,R)- and (S,S)-tartaric acid. The asymmetric unit of the unit cell of 1 consists of one molecule of (S,S)-diaminocyclohexane, one molecule of (R,R)-hydrogentartrate, half a molecule of (R,R)-tartaric acid, half of an (R,R)-tartrate anion, and a water molecule. The presence of all three ionisation states of (R,R)-tartrate in one crystal is most unusual, as is the anti conformation of the carboxyl group in (R,R)-tartaric acid. Association of (S,S)-diaminocyclohexane and (R,R) hydrogentartrate involves three-centre hydrogen bonds between ammonium groups as donors and alpha-hydroxycarboxylate and alpha-hydroxycarboxyl moieties as accepters. The remaining hydrogen bonds stabilise this motif and expand it to three dimensions. The results provide some insights into the enantioselective association of trans-1,2-diaminocyclohexane with optically active tartaric acids, the main driving force being the hydrogen bonding. While in a homochiral 1:1 salt the two ions combine by a scissors-shaped hydrogen bonding motif formed by two ammonium functions as donors and vicinal hydroxyl groups as accepters, in heterochiral salts the cation and anion species join together via three-centre hydrogen bonds between ammonium functions and planar or nearly planar alpha-hydroxycarboxylate moieties. (C) 1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/10/20 alle ore 16:20:07