Crown Ether Oxygen Atoms Research Articles

F-element/crown ether complexes. 13. Direct coordination of 12-crown-4 to hydrated terbium chloride. Synthesis and crystal structure of [Tb(OH 2) 5(12-crown-4)] Cl 3·2H 2O

The interaction of hydrated TbCl 3 with 12-crown- 4 in a 1:3 mixture of CH 3OH:CH 3CN produces crystalline [Tb(OH 2) 5(12-crown-4)]Cl 3·2H 2O. The crystal and molecular structure of this complex has been determined by single crystal X-ray diffraction techniques. It crystallizes in the orthorhombic space group Pna2 1 with a=18.758(3), b=10.080(2), c=10.242(2) Å, and D calc=1.95 g cm −3 for Z=4. Least-squares refinement using 1698 independent observed [ F O ≥ 5σ( F O)] reflections led to the final conventional R value of 0.033. The Tb(III) cation is coordinated to the four crown ether oxygen atoms (TbO average 2.52(1) Å and five water molecules in a capped square antiprismatic geometry. The capping water molecule is 2.504(7) Å from Tb, the remaining TbOH 2 separations average 2.38(2) Å. A complex network of hydrogen bonding connects the coordinated water molecules, the noncoordinated water molecules, and the chloride anions.