title: Trinuclear Cu(II) complexes of a chiral N6O3 amine.
abstract: Enantiopure trinuclear Cu(II) complexes 3 and 4 of macrocyclic amine 1 derived from the 3 + 3 condensation of 2,6-diformyl-4-methylphenol and (1S,2S)-1,2-diaminocyclohexane have been synthesized and characterized by ESI MS and NMR spectroscopy. The X-ray crystal structures of both complexes have been determined. The structure of the chloride derivative 3 indicates unusual combination of distorted tetragonal bipyramidal, square pyramidal and square geometries of the three Cu(II) ions bound by macrocycle 1. The acetate complex 4 also exhibits unsymmetrical trinuclear core with the bridging and terminal acetate anions. The complexation of Cu(II) ions by macrocycle 1 has been studied using potentiometric methods and both protonation and binding constants of 1 have been determined. The distribution of the complex forms indicates cooperative binding of three metal ions by 1. The overall magnetic behaviour for 3 corresponds to an antiferromagnetically coupled triangular system. Compound 4 shows the presence of antiferromagnetic coupling (J = -74.9(1) cm(-1)) between the metal centers in equilateral triangular array.
authors.affiliation: Department of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383, Wrocław, Poland. michal.kobylka@chem.uni.wroc.pl
authors.forename: Michał J
authors.initials: MJ
authors.lastname: Kobyłka
authors.forename: Jan
authors.initials: J
authors.lastname: Janczak
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Lis
authors.forename: Teresa
authors.initials: T
authors.lastname: Kowalik-Jankowska
authors.forename: Julia
authors.initials: J
authors.lastname: Kłak
authors.forename: Marta
authors.initials: M
authors.lastname: Pietruszka
authors.forename: Jerzy
authors.initials: J
authors.lastname: Lisowski