9,9 '-Spirobifluorene based zinc coordination polymers: a study on linker geometry and topology

Abstract : We report four Zn-based coordination polymers (CPs), synthesized from three spirobifluorene (SBF) tetracarboxylate ligands, possessing different topologies and dimensionalities. Zn-SBF-1, Zn-SBF-2 and Zn-SBF-3 CPs have 2D crystal structures with an sql topology built from square planar ligands (L1 and L3) and paddle-wheels for Zn-SBF-1 or original dimers of zinc for Zn-SBF-2 and Zn-SBF-3. Zn-SBF-4 is built from a ligand with a distorted tetrahedral geometry (L2) and an inorganic octahedral building unit resulting in a non-interpenetrated 3D porous framework with a toc topology. Structural relationships evidence that the meta (L2) versus para (L1 and L3) position of the carboxylic functions on the benzoate group of the SBF ligand increases the connectivity of the inorganic building unit and then the dimensionality of the framework.