Investigations of structure-property relationships in functional metal-organic frameworks

Abstract

Solids containing voids or empty spaces in their lattices which can be used for trapping gas or other molecules are called porous solids. The voids or empty spaces in these solids are occupied by guest or template molecules (usually solvent used in the synthesis) and can be removed by simple heating or evacuation. Zeolites and porous carbons are regarded as classical porous solids whose synthesis and properties have seen an enormous exploration (Figure 1). Recently, coordination compounds with infinite structures, commonly known as coordination polymers have gained enormous interest over the classical solids. A coordination polymer is an inorganic or an inorganic-organic polymeric structure containing metal ions/clusters linked by ligands (inorganic or organic) with an extended structure. In the first extended network compounds, the inorganic part contained either isolated polyhedra or small clusters. However, very soon, it was realized that these solids could possess inorganic part with larger dimensionality, giving rise to 1D chains, 2D sheets and 3D frameworks. The more general terms ‘MetalOrganic Framework’ (MOF) or ‘Porous Coordination Polymer’ (PCP) have later been coined and are widely accepted in the scientific community. MOFs or PCPs are crystalline compounds consisting of metal ions/clusters linked to organic bridging ligands to form one (1D), two (2D), three-dimensional (3D) structures that can be porous.