Enantioselective recognition of phenylalanine by a chiral amphiphilic macrocycle at the air-water interface: a copper-mediated mechanism.
The synthesis of a new chiral amphiphilic calix[4]resorcinarene, tetrakis(N-methylprolyl)tetraundecylcalix[4]resorcinarene (L-RA-Pro), bearing four L-prolyl moieties at the macrocyclic upper rim and four undecyl chains at the lower rim is described. This synthesis has been carried out via a Mannich-type reaction of L-proline and formaldehyde. It has been shown by means of Langmuir balance technique that L-RA-Pro self-assemble as well-defined monomolecular layers at the air-water interface. The effect of various cations on the stability of these monolayers has been studied. The experiments reveal that while there is a slight stabilization effect of K+, Cd2+, Co2+, Mg2+, and Ni2+, there is a high decrease in the collapse pressure in the presence of Cu(II) cation, showing that monolayers of L-RA-Pro, formed at the air-water interface, have a certain selectivity for copper(II) ions with regard to other cations tested. This supramolecular complex exhibits enantioselective recognition properties vs phenylalanine; the mechanism of this interaction is discussed.
Abteilung Chemie/Nano-Technologie, Fachhochschule beider Basel, Gründenstrasse 40, CH-4132 Muttenz, Switzerland. Patrick.Shahgaldian@unibas.ch
Patrick
P
Shahgaldian
Uwe
U
Pieles
Martin
M
Hegner
D000388:Air; D003300:Copper / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010649:Phenylalanine / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D014867:Water
D014867:Water; D010649:Phenylalanine; D003300:Copper