Crystal structure of an eight-coordinate terbium(III) ion chelated by N,N′-bis(2-hydroxybenzyl)-N,N′-bis(pyridin-2-ylmethyl)ethylenediamine (bbpen2−) and nitrate

Abstract

The reaction of terbium(III) nitrate pentahydrate in acetonitrile with N,N′-bis(2-hydroxybenzyl)-N,N′-bis(pyridin-2-ylmethyl)ethylenediamine (H2bbpen), previously deprotonated with triethylamine, produced the mononuclear compound [N,N′-bis(2-oxidobenzyl-κO)-N,N′-bis(pyridin-2-ylmethyl-κN)ethylenediamine-κ2N,N′](nitrato-κ2O,O′)terbium(III), [Tb(C28H28N4O2)(NO3)]. The molecule lies on a twofold rotation axis and the TbIII 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 N4O4 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).

Keywords

• crystal structure
• lanthanide
• terbium(III)
• N,N′-bis(2-hydroxybenzyl)-N,N′-bis(pyridin-2-ylmethyl)ethylenediamine
• mononuclear
• dodecahedral.