2024-03-29T10:35:26Zhttps://repositori.uji.es/oai/requestoai:repositori.uji.es:10234/1277682023-09-08T06:27:19Zcom_10234_7053com_10234_9col_10234_8639
00925njm 22002777a 4500
dc
Faggi, Enrico
author
Porcar Garcia, Raul
author
Bolte, Michael
author
Luis, Santiago V.
author
Garcia-Verdugo, Eduardo
author
Alfonso RodrÃguez, Ignacio
author
2014-09
A family of simple receptors formed by two or three cationic imidazolium arms attached to a central aromatic linkage and displaying different conformational flexibility has been synthesized from the enantiopure (1S,2S)-2-(1-H-imidazol-1-yl)-cyclohexanol. The crystal structures of the corresponding bromides of two of the hosts showed remarkable differences. The tripodal receptor with a trimethylated central benzene ring (1a) showed a cone-type conformation defining an inner anion-binding site, while the bipodal molecule with the central meta-phenylene spacer (m-2a) displayed an extended conformation. The binding properties of the chiral imidazolium hosts toward citrate, isocitrate and the two enantiomers of malate have been studied by 1H NMR titration experiments in 9:1 CD3CN:CD3OH at 298.15 K. Interestingly, 1a showed a stronger interaction with dianionic malate than with the trianionic citrate or isocitrate, suggesting that the smaller guest is better accommodated in the host cavity. Among this family, 1a proved to be the best receptor due to a combination of a larger number of electrostatic and H-bonding interactions and to a more efficient preorganization in the cone-type conformation. This preorganization effect is also present in solution as confirmed by 1H NMR spectroscopy.
FAGGI, Enrico, et al. Chiral Imidazolium Receptors for Citrate and Malate: The Importance of the Preorganization. The Journal of organic chemistry, 2014, 79.19: 9141-9149.
http://hdl.handle.net/10234/127768
http://dx.doi.org/10.1021/jo5014977
Citrates
Aromatic compounds
Binding energy
Crystallography
Nuclear magnetic resonance spectroscopy
Malates
Imidazole derivative
Chiral Imidazolium Receptors for Citrate and Malate: The Importance of the Preorganization