Syntheses and structure of nine-coordinate GdIII complexes, Na[GdIII(edta)(H2O)3]•5H2O and Na4[GdIII(dtpa)(H2O)]2•14H2O

The crystal and molecular structures of the Na-4[ Gd-III(edta)(H2O)(3) ].5H(2)O (edta = ethylenediaminetetraacetic acid) and Na-4[ Gd-III(dtpa) (H2O) ](2) . 14H(2)O (dtpa = diethylenetriaminepentaacetic acid) complexes were determined by single-crystal X-ray structure analyses. The crystal of the Na[Gd-III(edta)(H2O)(3)].5H(2)O belongs to orthorhombic crystal system and Fdd2 space group. The crystal data are as follows: a = 1.9424(7)nm, b = 3.5496(12)nm, c = 1.2125(4) nm, V = 8.360(5)nm(3), Z = 16, M = 612.63, D-c = 1. 947 g . cm(-3), mu = 3.274 mm(-1) and F (000) = 4880. The final R and wR values are 0.0295 and 0.0677 for 3102 [ I > 2.0 sigma (I) ] unique reflections, and 0.0328 and 0.0695 for all 8269 reflections, respectively. The [ Gd-III (edta) (H2O)(3) ]-complex anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which the nine coordinate atoms, two N and seven O are from one edta ligand and three coordinate water molecules. The crystal of the Na-4[Gd-III(dtpa)(H2O)](2).14H(2)O belongs to monoclinic crystal system and P2(1)/n space group. The crystal data are as follows: a = 1.4894 (6) nm, b = 1. 7987 (7) nm, c = 1. 9600 (7) nm, beta = 99.496 (7), V = 5. 179 (3) nm3, z = 4, M = 1471.44, D = 1. 841 g . cm(-3) mu = 2.676 mm(-1) and F (000) = 2872. The final R and wR are 0.0435 and 0. 0979 for 8929 [ I > 2.0 sigma ( I) ] unique reflections, and 0. 0820 and 0. 1167 for all 20717 reflections, respectively. The total complex moleculue is composed of two close parts in structure. The [ Gd-III ( dtpa) (H2O) ](2-) complex anion in the every part has a nine-coordinate structure with distorted monocapped square antiprismatic prism, in which the dtpa coordinates with central Gd-III ion acting as a octadentate ligand with three N atoms and five O atoms, and one water as the ninth ligand directly coordinates with central Gd-III ion.