@inbook{3d60740d1c654062954dbab5f6416673,
title = "Study of conformational behavior of CMP(O)-cavitands by NMR spectroscopy and X-ray analysis in relation to the extraction properties",
abstract = "Tetra-CMP(O)-functionalized cavitands are very effective europium(III) extractants. Cavitand 1b is the strongest ligand and has the highest extraction constant for 1:1 complexation with Eu(picrate)3 (viz. Kex 1 = 2.7 × 1012M−4). The conformational behavior of the CMP(O) cavitands 1a,b and 2a,b was studied by means of NMR spectroscopy. The introduction of an N-propyl substituent imposes large conformational differences due to inhibition of the free rotation around the amide N-C(O) bond. The Gibbs free energy of activation is about 75 kJ/mol for a rotation around the amide moiety (inwardoutward motion). The N-propyl-substituted cavitands form clusters; this aggregation originates from the association of propyl and pentyl chains of the cavitand molecules. The ability of bromomethylcavitand 3 to complex solvent molecules (e.g. CH2C12 or toluene) in the cavity is illustrated by a single crystal X-ray structure (with CH2C12).",
keywords = "Conformational behavior, Extraction property, ROESY spectrum, Amide moiety, Trivalent actinide",
author = "Harold Boerrigter and Willem Verboom and Ron Hulst and {van Hummel}, {Gerrit J.} and Sybolt Harkema and Reinhoudt, {David N.}",
year = "1999",
doi = "10.1007/978-94-011-4615-9_2",
language = "English",
isbn = "978-94-010-5950-3",
series = "NATO ASI Series",
publisher = "Kluwer Academic Publishers",
pages = "19--35",
editor = "M. Pons",
booktitle = "NMR in Supramolecular Chemistry",
address = "Netherlands",
}