Crystal structure of a Tb(III)-Cu(II) glycine-hydroxamate 15-metallacrown-5 sulfate complex.

The core of the title complex, bis-[hexa-aqua-hemi-aqua-penta-kis-(μ(3)-glycine-hydroxamato)sulfato-penta-copper(II)terbium(III)] sulfate hexa-hydrate, [TbCu(5)(SO(4))(GlyHA)(5)(H(2)O)(6.5)](2)(SO(4))·6H(2)O (1), which belongs to the 15-metalla-crown-5 family, consists of five glycine-hydroxamate dianions (GlyHA(2-); C(2)H(4)N(2)O(2)) and five copper(II) ions linked together forming a metallamacrocyclic moiety. The terbium(III) ion is connected to the centre of the metallamacrocycle through five hydroxamate oxygen atoms. The coordination environment of the Tb(3+) ion is completed to an octa-coordination level by oxygen atoms of a bidentate sulfate and an apically coordinated water mol-ecule, while the copper(II) atoms are square-planar, penta- or hexa-coordinate due to the apical coordination of water mol-ecules. Continuous shape calculations indicate that the coordination polyhedron of the Tb(3+) ion in 1 is best described as square anti-prismatic. The positive charge of each pair of [TbCu(5)(GlyHA)(5)(H(2)O)(6.5)(SO(4))](2) (2+) fragments is compensated by a non-coordinated sulfate anion, which is located on an inversion center with 1:1 disordered oxygen atoms. Complex 1 is isomorphous with the previously reported compounds [LnCu(5)(GlyHA)(5)(SO(4))(H(2)O)(6.5)](2)(SO(4)), where Ln (III) = Pr, Nd, Sm, Eu, Gd, Dy and Ho.