US scientists have used inorganic nodes in metal-organic frameworks (MOFs) as chelating ligand platforms for unusual coordination chemistry; using a MOF’s secondary building units for coordination chemistry is virtually unexplored.
They used the Zn4O secondary building units of the well known MOF-5 (Zn4O(1,4-benzenedicarboxylate)3) as tripodal chelating ligands and kinetically trapped a Ni2+ ion in an unusual tetrahedral all-oxygen ligand field. In doing so, they also demonstrated that MOFs can serve as veritable platforms for synthesising inorganic clusters (i.e. a NiZn3O(carboxylate)6 unit) that have no analogues in molecular chemistry.
Link to journal article
Lattice-Imposed Geometry in Metal-Organic Frameworks: Lacunary Zn4O Clusters in MOF-5 Serve as Tripodal Chelating Ligands for Ni2+
C K Brozek and M Dinca
Chem. Sci., 2012, DOI: 10.1039/c2sc20306e