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Adrenaline Recognition in Water
Author(s) -
Molt Oliver,
Rübeling Daniel,
Schäfer Gerhard,
Schrader Thomas
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400100
Subject(s) - chemistry , hydrogen bond , hydrophobic effect , micelle , molecule , monolayer , amphiphile , ionic bonding , phosphonate , covalent bond , pyrene , non covalent interactions , selectivity , stereochemistry , aqueous solution , organic chemistry , polymer , ion , biochemistry , catalysis , copolymer
Host molecule 1 displays a high affinity in water towards catecholamines and especially related structures such as β‐blockers with extended aromatic π‐faces (up to 7×10 3 M −1 for each single complexation step or 5×10 7 M −2 for both steps). The amphiphilic structural design leads to an extensive self‐association of host molecules through their aromatic flanks. Above a cmc (critical micelle concentration) of 3×10 −4 M , host 1 forms micelles that produce a favorable microenvironment for hydrophobic interactions with the included guest molecules. Electrostatic attraction of the ammonium alcohol by the phosphonate anions is thus combined with hydrophobic contributions between the aromatic moieties. Ionic hydrogen bonds with polar OH or NH groups of the guest enforce the non‐covalent interactions, and finally lead to increased specificity. Both its affinity and its selectivity towards adrenergic receptor substrates are greatly enhanced if the receptor molecule 1 is transferred from water into a lipid monolayer. Catecholamines and β‐blockers lead to drastically different effects at concentrations approaching the micromolar regime. Especially β‐blockers with minute structural changes can be easily distinguished from each other. In both cases, extensive hydrophobic interactions with a self‐associated and/or self‐organized microenvironment are largely responsible for the observed high efficiency and specificity.