Syntheses and Structure Determination of Nine-Coordinate (NH4)3[TbIII(nta)2(H2O)]·4H2O and Eight-Coordinate (NH4)3[ErIII(nta)2] Complexes

Abstract

Syntheses and structure determination of TbIII and ErIII 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[TbIII(nta)2(H2O)]·4H2O complex belongs to the monoclinic crystal system and C2/c space group. Crystal data are as follows: a = 16.357(8) A, b = 8.552(4) A, c = 17.390(9) A, β = 104.748(7)°, V = 2352.6(19) A3, Z = 4, Mr = 675.32, Dc = 1.932 g·cm−3, μ = 3.112 mm−1, and F(000) = 1368. The final R and Rw are 0.0220 and 0.0494 for 2357 (I > 2σ(I)) unique reflections, R and Rw are 0.0266 and 0.0510 for all 5613 reflections, respectively. The TbIIIN2O7 moiety in the [TbIII(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 TbIII ion directly as the ninth coordinate atom. The crystal of the (NH4)3[ErIII(nta)2] complex belongs to the trigonal crystal system and R-3c space group. Crystal data are as follows: a = 7.9181(16) A, b = 7.9181(16) A, c = 54.27(2) A, γ = 120°, V = 2946.7(14) A3, Z = 6, Mr = 597.61, Dc = 2.021 g·cm−3, μ = 4.345 mm−1, and F(000) = 1770. The final R and Rw are 0.0295 and 0.0673 for 677 (I > 2σ(I)) unique reflections, R and Rw are 0.0366 and 0.0700 for all 4827 reflections, respectively. The ErIIIN2O6 part in the [ErIII(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.