Nine-coordinate rare earth metal complexes with aminopolycarboxylic acids: Mononuclear (NH4)(3)[Tb-III(ttha)]center dot 5H(2)O and binuclear (NH4)(4)[Tb-2(III)(dtpa)(2)]center dot 9H(2)O

The two title coordination compounds, (NH4)(3)[Tb-III(ttha)]center dot 5H(2)O (ttha = triethylenetetramine-N,N,N',N'', N''',N'''-hexaacetic acid) and (NH4)(4)[Tb-2(III)(ttha)]center dot 9H(2)O (dtpa = diethylenetriamine-N,N,N',N'',N''-pentaacetic acid), have been prepared and characterized by FT-IR, elemental analyses, TG-DTA and single crystal X-ray diffraction techniques. The (NH4)(3)[Tb-III(ttha)]center dot 5H(2)O compound is monoclinic, P2(1)/c; a = 10.398(1) angstrom, b = 12.791(1) angstrom, c = 23.199(2)angstrom; beta = 90.914(2)degrees; V = 3084.9(5)angstrom(3); Z = 4; D (calc) = 1.704 g/cm(3); mu(MoK (alpha) ) = 2.376 mm(-1); R = 0.023 and wR(2) = 0.049 for 5429 observed reflections with I >= 2 sigma(I). The [Tb-III(ttha)](3-) complex anion in the crystal has a nine-coordinate mononuclear molecular structure with pseudo-monocapped square-antiprismatic configuration. The (NH4)(4)[Tb-2(III)(dtpa)(2)]center dot 9H(2)O compound is triclinic, P-1; a = 9.739(1)angstrom, b = 10.010(1)angstrom, c = 12.968(2)angstrom; alpha= 85.890(2)degrees, beta = 77.338(2)degrees, gamma = 77.587(2)degrees; V = 1204.2(2) angstrom(3); Z = 1; D (calc) = 1.832 g/cm(3); mu(MoK (alpha) ) = 3.015 mm(-1); R = 0.024 and wR(2) = 0.060 for 4750 observed reflections with I >= 2 sigma(I). The [Tb-2(III)(dtpa)(2)](4-) complex anion has a binuclear structure in the crystal; the two Tb-III centers are equivalent and have a nine-coordinate environment with the same pseudo-tricapped trigonal-prismatic configuration. The thermal analysis revealed that the coordination cores of the (NH4)(3)[Tb-III(ttha)]center dot 5H(2)O and (NH4)(4)[Tb-2(III)(dtpa)(2)]center dot 9H(2)O compounds are stable up to 221 degrees C and 252 degrees C, respectively.