title: Electronic effects in 12-metallacrown-3 complexes. A theoretical and experimental study.
abstract: The Mulliken charges of the 12-metallacrown-3 complex [(C(6)H(6))Ru(C(5)H(3)NO(2))](3) were determined by a single point analysis at the HF level. For comparison, a Mulliken population analysis was carried out for the organic analogue 12-crown-3. The partial negative charges on the O-donor atoms of the metallamacrocycle were found to be larger than those on the O-donor atoms of 12-crown-3. The 12-metallacrown-3 complex [(cymene)Ru(C(5)H(2)ClNO(2))](3) with chloro-substituents in position 5 of the pyridonate ligand was synthesized to determine the effect of electron withdrawing groups on the structure and the host-guest properties of the receptor. The chloro-substituents were found to have only a small influence on the structures, but they reduce the binding affinity for LiCl and NaCl by approximately 2 orders of magnitude.
authors.affiliation: Institut de Chimie Moléculaire et Biologique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Marie-Line
authors.initials: ML
authors.lastname: Lehaire
authors.forename: Axel
authors.initials: A
authors.lastname: Schulz
authors.forename: Rosario
authors.initials: R
authors.lastname: Scopelliti
authors.forename: Kay
authors.initials: K
authors.lastname: Severin