Syntheses and structure determination of nine-coordinate (NH4)3[TbIII (nta)2(H2O)]• 4H2O and eight-coordinate (NH4)3[ErIII(nta)2] complexes

Syntheses and structure determination of Tb-III and Er-III complexes with nitrilotriacetic acids (nta) are reported. Their crystal and molecular structures, molecular formulas, and compositions were determined by single-crystal X-ray structure analyses and elementary analyses, respectively. The crystal of the (NH4)(3)[Tb-III(nta)(2)(H2O)](.)4H(2)O complex belongs to the monoclinic crystal system and C2/c space group. Crystal data are as follows: a = 16.357(8) angstrom, b = 8.552(4) angstrom, c = 17.390(9) angstrom, beta = 104.748(7)degrees, V = 2352.6(19) angstrom(3), Z = 4, Mr = 675.32, D-c = 1.932 g(.)cm(-3), mu = 3.112 min(-1), and F(000) = 1368. The final R and Rw are 0.0220 and 0.0494 for 2357 (I > 2 sigma(I)) unique reflections, R and Rw are 0.0266 and 0.0510 for all 5613 reflections, respectively. The (Tb2O7)-O-III moiety in the [Tb-III(nta)(2)(H2O)](3-) complex anion has a pseudo-monocapped square antiprismatic nine-coordinate structure, in which the eight coordinate atoms (two N and six O) are from two nta ligands and the water molecule is coordinated to the central Tb-III ion directly as the ninth coordinate atom. The crystal of the (NH4)(3)[Er-III(nta)(2)] complex belongs to the trigonal crystal system and R-3c space group. Crystal data are as follows: a = 7.9181(16) angstrom, b = 7.9181(16) angstrom, c = 54.27(2) angstrom, gamma = 120 degrees, V= 2946.7(14) angstrom(3), Z = 6, Mr = 597.61, D-c = 2.021 g(.)cm(-3), mu = 4.345 mm(-1), and F(000) = 1770. The final R and Rw are 0.0295 and 0.0673 for 677 (I > 2 sigma(I)) unique reflections, R and Rw are 0.0366 and 0.0700 for all 4827 reflections, respectively. The (ErN2O6)-N-III part in the [Er-III(nta)(2)](3-) complex anion is an eight-coordinate structure with a pseudo-dicapped octahedron, in which the eight coordinate atoms (two N and six O) are from two nta ligands.