Skip to main content
padlock icon - secure page this page is secure

Structural trends in a series of isostructural lanthanide–copper metallacrown sulfates (Ln

Buy Article:

$52.00 + tax (Refund Policy)

The seven isostructural complexes, [Cu5Ln(C2H4N2O2)5(SO4)(H2O)6.5]2(SO4)·6H2O, where LnIII = Pr, Nd, Sm, Eu, Gd, Dy and Ho, are representatives of the 15‐metallacrown‐5 family. Each dianion of glycinehydroxamic acid (GlyHA) links two CuII cations forming a cyclic [CuGlyHA]5 frame. The LnIII cations are located at the centre of the [CuGlyHA]5 rings and are bound by the five hydroxamate O atoms in the equatorial plane. Five water molecules are coordinated to CuII cations, and one further water molecule, located close to an inversion centre between two adjacent [Cu5Ln(GlyHA)5]2+ cations, is disordered around this inversion centre and coordinated to a CuII cation of either the first or second metallacrown ether. Another water molecule and one of the two crystallographically independent sulfate anions are coordinated, the latter in a bidentate fashion, to the LnIII cation in the axial positions. The second sulfate anion is not coordinated to the cation, but is located in an interstitial position on a crystallographic inversion centre, thus leading to disorder of the O atoms around the centre of inversion. The Ln—O bond distances follow the trend of the lanthanide contraction. The apical Ln—O bond distances are very close to the sums of the ionic radii. However, the Ln—O distances within the metallacrown units are slightly compressed and the LnIII cations protrude significantly from the plane of the otherwise flat metallacrown ligand, thus indicating that the cavity is somewhat too small to accommodate the LnIII ions comfortably. This effect decreases with the size of the lanthanide cation from complex (I) (LnIII = Pr; 0.459 Å) to complex (VII) (LnIII = Ho; 0.422 Å), which indicates that the smaller lanthanide cations fit the cavity of the pentacopper metallacrown ring better than the larger ones. The diminished contraction of Ln—O distances within the metallacrown planes leads to an aniostropic contraction of the unit‐cell parameters, with a, c and V following the trend of the lanthanide contraction. The b axes, which are mostly aligned with the rigid planes of the metallacrown units, show only a little variation between the seven compounds.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Document Type: Research Article

Publication date: July 15, 2011

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more