STRUCTURAL AND SPECTROSCOPIC CHARACTERIZATION OF THE MACROCYCLIC COMPLEX - [TB(CRO4)(H2O)(C22H26N6)]CENTER-DOT-0.5(CR2O7) (H2O)

The title complex was obtained by anion metathesis from [Tb(CH3COO)2(C 22H26N6)] (CH3COO). 4H(2)O and K2CrO4 in aqueous solution. The compoun d crystallizes in the triclinic space group P $($) over bar$$ 1 with a = 8.384(2), b = 10.425(2) c = 15.752(2)Angstrom, alpha = 98.82(2), be ta = 93.52(2), gamma = 97.22(2)degrees, and Z = 2. The structure is io nic and consists of a (+1) complex cation balanced in a 2:1 ratio by a disordered dichromate ion. The 9-coordinate Tb(III) is linked to the six nitrogen atoms of the macrocyclic ligand L = C22H26N6, as well as to a water molecule and a bidentate chelating chromate situated on opp osite sides of the macrocycle. The infrared spectrum shows, in additio n to the pattern of the macrocyclic ligand, the absorptions arising fr om the stretching modes of the bidentate chelating CrO42- ligand and o f the Cr2O72- counterion.