Crystal structure of an eight-coordinate terbium(III) ion chelated by N,N '-bis(2-hydroxybenzyl)-N,N '-bis(pyridin-2-ylmethyl)ethylenediamine (bbpen(2-)) and nitrate

The reaction of terbium(III) nitrate pentahydrate in acetonitrile with N,N'-bis(2-hydroxybenzy1)-N,N'-bis(pyridin-2-ylmethyl)ethylenediamine (H(2)bbpen), previously deprotonated with triethylamine, produced the mononuclear compound[N,N'-bis(2-oxidobenzyl-kappa O)-N,N'-bis(pyridin-2-ylmethyl-kappa N)ethyl-enediamine-kappa(2) N,N'] (nitrato-(KO)-O-2,O')terbium (III), [Tb (C28H28N4O2) (NO3)]. The molecule lies on a twofold rotation axis and the TWIT ion is eight-coordinate with a slightly distorted dodecahedral coordination geometry. In the symmetry unique part of the molecule, the pyridine and benzene rings are both essentially planar and form a dihedral angle of 61.42 (7)degrees. In the molecular structure, the N4O4 coordination environment is defined by the hexadentate bbpen ligand and the bidentate nitrate anion. In the crystal, a weak C-H center dot center dot center dot O hydrogen bond links molecules into a two-dimensional network parallel to (001).