Syntheses and structural determination of nine-coordinate K 3[Nd III(nta) 2(H 2O)]·6H 2O and K 3[Er III(nta) 2(H 2O)]·5H 2O

Abstract

The syntheses and structural determination of the Nd III and Er III complexes with nitrilotriacetic acid (nta) were reported in this paper. Their crystal and molecular structures and compositions were determined by single-crystal X-ray structure analyses and elemental analyses, respectively. The crystal of the K 3[Nd III(nta) 2(H 2O)]·6H 2O complex belongs to monoclinic crystal system and C2/ c space group. The crystal data are as follows: a=1.5490(11) nm, b=1.3028(9) nm, c=2.6237(18) nm, β=96.803(10)°, V=5.257(6) nm 3, Z=8, M=763.89, D c =1.930 g cm −3, μ=2.535 mm −1 and F(000)=3048. The final R 1 and wR 1 are 0.0390 and 0.0703 for 4501 ( I>2 σ( I)) unique reflections, R 2 and wR 2 are 0.0758 and 0.0783 for all 10474 reflections, respectively. The Nd IIIN 2O 7 part in the [Nd III(nta) 2(H 2O)] 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 a water molecule coordinate to the central Nd III ion directly. The crystal of the K 3[Er III(nta) 2(H 2O)]·5H 2O complex also belongs to monoclinic crystal system and C2/ c space group. The crystal data are as follows: a=1.5343(5) nm, b=1.2880(4) nm, c=2.6154(8) nm, β=96.033(5)°, V=5.140(3) nm 3, Z=8, M=768.89, D c =1.987 g cm −3, μ=3.833 mm −1 and F(000)=3032. The final R 1 and wR 1 are 0.0321 and 0.0671 for 4445 ( I>2 σ( I)) unique reflections, R 2 and wR 2 are 0.0432 and 0.0699 for all 10207 reflections, respectively. The Er IIIN 2O 7 part in the [Er III(nta) 2(H 2O)] 3− complex anion has the same structure as Nd IIIN 2O 7 part in which the eight coordinate atoms (two N and six O) are from two nta ligands and a water molecule coordinate to the central Nd III ion directly.