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-hy­droxy­benz­yl)-N,N′-bis­(pyridin-2-ylmeth­yl)ethyl­enedi­amine (H(2)bbpen), previously deprotonated with tri­ethyl­amine, produced the mononuclear compound [N,N′-bis­(2-oxidobenzyl-κO)-N,N′-bis­(pyridin-2-ylmethyl-κN)ethylenedi­amine-κ(2) N,N′](nitrato-κ(2) O,O′)terbium(III), [Tb(C(28)H(28)N(4)O(2))(NO(3))]. The mol­ecule lies on a twofold rotation axis and the Tb(III) 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)°. In the mol­ecular structure, the N(4)O(4) coordination environment is defined by the hexa­dentate bbpen ligand and the bidentate nitrate anion. In the crystal, a weak C—H⋯O hydrogen bond links mol­ecules into a two-dimensional network parallel to (001).