Abstract:
Until the period of mid 1990s, there were mainly two kinds of porous materials, viz. inorganic material and carbon based material. At that time, zeolites and porous carbons were considered as classical porous solids.1 However, their tedious synthetic conditions and limitations in tuning the porosity forced the scientists to conceive different strategies to discover new materials (Figure 1). The last two decades have witnessed an accomplished development in designing a different type of porous material which is concerned with the linking of metal ions or metal-oxygen clusters (known as secondary building unit (SBU)2) with organic bridges by strong chemical bonds to form crystalline, extended structures.3 This new type of porous materials which are well known as metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) are widely accepted in the scientific community, and creates a colligating bridge between molecular coordination chemistry and materials science. In the history of coordination polymers (CPs), extensive research had been focused only on isolated polyhedral, mononuclear cluster and their different properties. However, very soon it was realized that these isolated structures can be extended to higher dimensionality, giving rise to 1D chain, 2D sheets or 3D framework porous architectures.
