MOLECULAR AND CRYSTAL-STRUCTURE OF A LANTHANIDE COMPLEX, DYDTPA-BMA HYDRATE

1,7-Bis-[N-methylcarbamoyl)methyl]-1,4,7-triazaheptane-1,4,7-triacetic acid dysprosium(III) hydrate, DyDTPA-BMA hydrate, C16H40DyN5O15, M(w) = 705.0 g mol-1, crystallizes in a monoclinic cell, P2(1)/n, Z = 4. The cell dimensions are a = 9.358(2), b = 25.187(4), c = 12.009(2) angstrom, beta = 109.52(1)-degrees and V = 2667.6(8) angstrom 3. T = 120 K, D(calc) = 1.76 Mg m-3, lambda(MoK-alpha) = 0.710 69 angstrom, F(000) = 1416. R = 0.024 for 4543 unique reflections. The compound crystallizes as discrete nonionic (8 + 1) coordinate dysprosium complexes. Eight of the ligands are three amine nitrogen atoms, three carboxyl oxygen atoms and two amide oxygen atoms. The ninth ligand is a water molecule. There is no particular strain in the complex: distances and angles in the ligand are of normal values. The Dy-O distances are shorter than the sum of the respective ionic radii, and the Dy-N distances are longer. The resulting complex has one hydrophobic and one hydrophilic side. The ligating water molecule is bonded on the latter side, where the water molecules of crystallization also appear in highest concentration. The complex is hydrogen-bonded to water molecules and to other complexes, making a three-dimensional network. There are no intramolecular hydrogen bonds.