Abstract:
Porous materials, owing to their multifaceted applications, have attracted the
attention of materials scientists all over the world since the creation of nanometer sized
spaces give rise to many interesting applications, e.g., gas storage, separation, catalysis,
sensing, etc. Porous materials can be broadly classified in four different classes, namely
inorganic (e.g., zeolites, mesoporous silica), organic (e.g., covalent organic frameworks,
conjugated microporous polymers), carbon materials and organic-inorganic hybrid
materials, e.g., porous coordination polymers (PCPs), or metal-organic frameworks
(MOF) (Fig. 1). Zeolites, which are microporous aluminosilicates, are the torchbearers of
inorganic porous materials, and have been used extensively as microporous materials for
adsorption and separation of industrially important feedstocks, catalysis and ionexchangers
owing to their extra-framework cation.1, 2 However, zeolites are rather rigid in
nature and do not allow functionalization and tuning of the pore surface and hence
selective sequestration and signalling is not possible in them.3 Mesoporous silica is
another class of inorganic porous materials which have been used extensively for
catalysis and drug delivery. Pure organic porous materials include covalent organic
frameworks (COFs) and conjugated microporous polymers (CMP). Although these show
large surface areas and good porosity, the synthetic procedures are rather tedious and lack
structural control and these materials cannot be tuned easily. The third class of porous
materials, activated carbons, have open porous structures with high surface area but the
structure is essentially disordered.4,
