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Keywords:

  • Lanthanides;
  • Cubane;
  • Poro­sity;
  • Single-molecule magnets;
  • Magnetic properties;
  • Metal–organic frameworks

Abstract

The reaction of isonicotinic acid N-oxide and Dy(NO)3·6H2O under aerobic conditions leads to the formation of a porous lanthanide, a cubane-based 3D edifice of the formula [Dy43-OH)33-O)(NOPyCOO)6(OH)(H2O)3·(DMF)3(H2O)12] (NOPyCOO = pyridine-4-carboxylate N-oxide). Crystal structure investigations show that the [Dy43-OH)33-O)] cubane cores are interconnected by organic ligands to form an extended porous structure. Thermogravimetric analyses and temperature-dependent X-ray diffraction analyses evidence that the compound is stable upon dehydration/desolvatation up to 200 °C. Calculations for the N2 kinetic radius afford a void volume of 3603 Å3 per unit cell (33.8 %) and a potential porosity of 1400 m2 g–1. The large pores can potentially host molecules with a projected surface area as large as 20 Å2 into a large pore volume (600 Å3). Moreover, the onset of a slow magnetic relaxation has been observed and rationalized by a comparison with closely related 0D and 2D compounds.