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Bis(diamido)‐Bridged Basket Resorcin[4]arenes as Enantioselective Receptors for Amino Acids and Amines

2007; Wiley; Volume: 2007; Issue: 36 Linguagem: Inglês

10.1002/ejoc.200700829

1434-193X

Bruno Botta, Ilaria D’Acquarica, Laura Nevola, Fabiola Sacco, Zara Valbuena Lopez, Giovanni Zappia, Caterina Fraschetti, Maurizio Speranza, Andrea Tafi, Fabiana Caporuscio, Matthias C. Letzel, Jochen Mattay,

Molecular Sensors and Ion Detection

Abstract On the research avenue opened by the rigidified double‐spanned resorcin[4]arene 1 , we have synthesized both enantiomers of the two chiral basket resorcin[4]arenes 3 and 4 , each containing two 1,2‐diaminocyclohexane and 1,2‐diphenylethylenediamine bridges, respectively. In the new compounds, the aromatic rims assume the expected flattened cone arrangement, whereas two different conformations, tentatively designated as “open wings” and “folded wings”, were attributed to the bridge substituents according to molecular modeling studies. In MS n (ESI) experiments, the proton‐bonded diastereomeric [ 4· H · A] + complexes with amino acidic guests (A) exhibited a pronounced selectivity towards the enantiomers of tyrosine methyl ester (tyr OMe ) and amphetamine (amph), whereas the chirality of tryptophan (trp) was ineffective. Moreover, a kinetic study on the base‐induced displacement of the guest revealed that the L ‐tyr OMe (and L ‐amph) enantiomer is faster displaced from the heterochiral [ 4· H · L ‐ tyr OMe ] + (or [ ent ‐ 4· H · l ‐ amph] + ) complex than from the homochiral [ ent ‐ 4· H · L ‐ tyr OMe ] + (or [ 4· H · l ‐ amph] + ) one. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)