Tris(6-carb-oxy-pyridine-2-carboxyl-ato)terbium(III) 2.75-hydrate

Abstract

In the title compound, [Tb(C(7)H(4)NO(4))(3)]·2.75H(2)O, the Tb(3+) atom is coordinated by three tridentate 6-carb-oxy-pyridine-2-carboxyl-ate ligands and lies on a crystallographic threefold rotation axis. The coordination polyhedron around Tb(III) adopts a distorted tricapped trigonal-prismatic geometry. Disordered water mol-ecules with partial occupancy are also present in the crystal, one of which is associated with each of the carboxyl-ate O atoms of the complex unit.

Fig. 1.

ORTEP view of the terbium tris(dipicolinate) complex (along the c axis) showing the threefold symmetry, the atom-numbering and the displacement ellipsoids with 50% probability. For symmetry codes: (i) -x + y, -x + 1, z; (ii) -y + 1, x-y + 1, z.

Fig. 2.

Phosphorescence spectrum of the title compound (solid state, RT).

Fig. 3.

IR spectrum of the title compound (solid state, RT).

Fig. 4.

Schematic representation of three facial planes containing donor atoms in title compound.

Fig. 5.

Crystal packing of the title compound showing the unit-cell contents and the disordered partial water molecules in the channels (a) viewed along the c axis and (b) viewed along the a axis.