‘2E−2N squares’: Chalcogen (E=S, Se and Te) Bonding Involving Benzochalcogenodiazoles

Several intra and intermolecular interactions (secondary bonding interactions, SBIs) such as halogen bonding (XB), hydrogen bonding (HB) have great impact on crystal engineering, from catalysis to material and pharmaceutical applications. With respect to other interactions chalcogen (S, Se and Te) bonding (ChB) is less explored until very recently, although it has great potential to evolve in larger domain. In literature there are several reports on ChB and their roles in solid-state packing of molecular materials having benzochalcogenodiazole as an active moiety applicable in organic electronics. Some important and informative reviews on ChB and their various applications in catalysis and structural properties relationship were also presented. Here purpose of this review is to summarize the ChB involved in pi-conjugated molecular system having benzochalcogenodiazole to form '2E-2N square' which seems to be very important supramolecular synthon involving ChB.