[00.5] JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 (7) 1315-1321 2000
Cation coordination by calixarenes bearing amide and/or phosphine oxide pendant groups: how many arms are needed to bind Li+ vs. Na+? A combined NMR and molecular dynamics study
Marc Baaden, Georges Wipff1,* Mohammad Reza Yaftian 2, Michel Burgard 2, Dominique Matt 3
Combined spectroscopic and theoretical studies have been performed on two recently developed calixarenes in the cone conformation, L1 (bearing two -CH2C(O)NEt2 and two -CH2P(O)Ph-2 substituents occupying respectively distal phenolic positions) and L2 (with four -CH2P(O)Ph-2 substituents), in order to compare the Li+ vs. Na+ cation binding mode. Molecular dynamics simulations indicate that coordination of the Li+ cation involves three of the four substituents (the two phosphoryl groups and one of the two amide functions of L1; three phosphoryl arms of L2). A variable temperature NMR study carried out with L1 . Li+ confirms this fourfold coordination and reveals that in solution the lithium cation moves between the two adjacent OPOPOamide units. The weaker binding of the Na+ cation results in a more symmetrical coordination of the four phenolic oxygen atoms and two carbonyls of L1 or four phosphoryls of L2.
Two typographic errors concerning atomic charges were made.
- In the amide fragment, the alpha amide carbon is not charged -0.323 but +0.323.
- In the phosphine-oxide, the bottom HA is indicated as 0.0122 but should read 0.122
|Article 2000.5 (Perkin Trans 2, 1315)|
Correspondence should be addressed to Prof. G. Wipff.
- Univ Strasbourg 1, CNRS, UMR 7551, Inst Chim, 4 Rue B Pascal, F-67000 Strasbourg, France.
- Univ Strasbourg 1, Lab Chim Minerale & Chim Phys Ind, ECPM, UMR CNRS 7512, F-67087 Strasbourg, France.
- Univ Strasbourg 1, Grp Chim Inorgan Mol, UMR CNRS 7513, F-67008 Strasbourg, France.
7 times cited on 2/2/2005 (Ref. ISI Web Of Science)