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Multipoint Recognition of Catecholamines by Hydrindacene‐Based Receptors Accompanied by the Complexation‐Induced Conformational Switching
Author(s) -
Kawai Hidetoshi,
Katoono Ryo,
Fujiwara Kenshu,
Tsuji Takashi,
Suzuki Takanori
Publication year - 2005
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.200400819
Subject(s) - conformational isomerism , chemistry , intramolecular force , amide , hydrogen bond , molecule , receptor , stereochemistry , molecular recognition , organic chemistry , biochemistry
The molecular recognition of catecholamines by hydrindacene‐based receptors 1 and 2 , as well as the durene‐based receptor 3 , and the guest‐induced conformational changes are reported. These receptors selectively bind adrenaline and dopamine salts through the guests' ammonium group and 3‐hydroxyl group on the aromatic ring. In the case of adrenaline, an additional hydrogen bond with a benzylic hydroxyl group is formed. In 2 % CD 3 CN/CDCl 3 , the association constants are of the order of 10 4 M −1 , which is much larger than with guests without the 3‐hydroxyl groups (10 3 M −1 ). The two amide groups of receptor 1 can rotate freely around the C aromatic C amide bond, whereas the tert ‐amide in 2 changes between two stable conformations at a slow enough rate to allow detection by 1 H NMR spectroscopy. In the absence of a guest molecule, the syn ‐conformer is less stable than the anti ‐conformer. On complex formation with adrenaline, the syn ‐conformer becomes dominant due to an intramolecular dipole‐reversal effect in addition to multipoint hydrogen bonding.