Investigation of flexible and anionic metal-organic frameworks and derived materials for energy and environmental applications

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,