The influence of the coordination environment of cobalt(ii) ions on the magnetic properties of heterometallic complexes with a {Co2Li2} metal core

Abstract

Five new heterometallic carboxylate complexes of the composition [Co₂Li₂(A)₆(L)₂] (L = 4-phenylpyridine, A = 2-furoate anion (1); L = 2,2′-bipyridine, A = 2-furoate anion (2), 3,5-di-tert-butylbenzoate anion (3); L = quinoline, A = 3-cyanobenzoate anion (4), 4-cyanobenzoate anion (5)) were synthesized. The structures of all compounds were determined by single-crystal X-ray diffraction. When monodentate N-donor ligands are replaced by chelating 2,2′-bipyridine, the coordination polyhedron of cobalt ions changes from a distorted tetrahedron to a distorted octahedron. Complexes 1–4 are field induced single-molecule magnets. Mechanisms of slow magnetic relaxation are discussed taking into account both experimental data and quantum chemical calculations.