Metal complexes of C-2-symmetric chiral bipyridine ligands. X-ray structure of [bis(nitrato)(4S,5S)-2,2-dimethyl-4,5-bis(2-pyridyl)-1,3-dioxolane cobalt(II)]

Chelating properties of C-2-symmetric chiral bipyridine ligands are discuss ed. In particular we report the syntheses of the cobalt(II), nickel(II), zi nc(II) and copper(II) complexes of (4S,5S)-2,2-dimethyl-4,5-bis(2-pyridyl)- 1,3-dioxolane. All compounds have been characterized by IR spectroscopy, an d an X-ray diffraction analysis has been carried out on one of them: Co(L)( NO3)(2). The ligand coordinates the cobalt atom by the two nitrogen donors N(1) and N(2). A seven-membered chelation ring is formed, presenting a rema rkable non-crystallographic twofold pseudosymmetry around the axis connecti ng Co and the midpoint of the C(6)-C(7) bond. The metal also binds two mono dentate nitrates, thus completing a distorted coordination tetrahedron.