Selective recognition and extraction of iodide from pure water by a tripodal selenoimidazol(ium)-based chalcogen bonding receptor
Abu Saleh Musha Islam, Sourav Pramanik, Sahidul Mondal, Rajib Ghosh, Pradyut Ghosh
Abstract
A selenium-based tripodal chalcogen bond (ChB) donor TPI-3Se is demonstrated for the recognition and extraction of I − from 100% water medium. NMR and ITC studies with the halides reveal that the ChB donor selectively binds with the large, weakly hydrated I − . Interestingly, I − crystallizes out selectively in the presence of other halides supporting the superiority of the selective recognition of I − . The X-ray structure of the ChB-iodide complex manifests both the μ 1 and μ 2 coordinated interactions, which is rare in the C–Se···I chalcogen bonding. Furthermore, to validate the selective I − binding potency of TPI-3Se in pure water, comparisons are made with its hydrogen and halogen bond donor analogs. The computational analysis also provides the mode of I − recognition by TPI-3Se. Importantly, this receptor is capable of extracting I − from pure water through selenium sigma-hole and I − interaction with a high degree of efficiency (∼70%).