Pillars, layers, pores and networks from nickeltripyrrins: a porphyrin fragment as a versatile building block for the construction of supramolecular assemblies.

Sterically hindered nickel- tripyrrins [Ni(trpy)X] with different di-, tri- and tetradentate anions X have been prepared with the aim of finding coordination polymers formed by self-association. The syntheses were performed by simple ligand-exchange reactions and proceeded successfully with the pseudohalides CN(-), OCN(-), SCN(-), SeCN(-), N(CN)(2) (-) (dicyanoamido, dca) and C(CN)(3) (-) (tricyanomethanido, tcm), the cyanidometallates [Ag(CN)(2)](-) and [Ni(CN)(4)](2-) and the salicylate anion (sal(-)). X-ray crystallographic analyses revealed that the complexes with cyanido and isocyanato ligands, as well as the compound with a salicylato ligand, are prototypes for structurally distinct monomeric species in the solid state, whereas one-dimensional coordination polymers or supramolecular three-dimensional networks are formed from all other combinations. The polymeric compounds display a variety of individual pillar and network architectures with functionalised pores and clefts and with the Ni(trpy) fragments in different relative orientations. Hydrogen bonding and pi stacking were found to be additional structure-directing effects, which increased the structural complexity of the system. The Ni(trpy) subunit has thus been proven to be a versatile building block for the construction of supramolecular assemblies and metal organic frameworks (MOFs) from pentacoordinate Ni(II) ions.