11-12
S. Tanase, M.C. Mittelmeijer-Hazeleger,
G. Rothenberg, C. Mathonière, V. Jubera,
J.M.M. Smits, R. de Gelder,
A facile building-block synthesis of multifunctional
lanthanide MOFs,
J. Matter. Chem. 21 (2011) 15544-15551
Abstract
We report a building blocks approach providing a direct route to
multifunctional MOFs, that display photoluminescent
properties, robustness, porosity and in some cases unique magnetic properties.
The self-assembly of [Mo(CN)(8)](4-) with several in situ prepared lanthanide
building blocks gives 3D robust porous networks with open channels. This
approach solves the coordination problem, allowing exact placement of the
lanthanide ions within the structure. Our MOFs feature good thermal stability
and permanent porosity thanks to the strong carboxylate
and cyanide linkages. The fact that we have both nitrogen-containing ligand and a pi-system means that these MOFs can be excited
using low-energy photons. Efficient visible emission was observed for MOFs
containing Eu(III) and Tb(III). Surprisingly, the
Tb-MOF shows ferromagnetic behavior, proving that the magnetic interaction
between Tb(III) ions is strong enough to compensate the ligand
field effects.