One of the supreme anion binding building blocks exhibiting strong interplay among topology, complementarity and coordination over the last two decades is the tris(2-aminoethyl)amine skeleton. However, recognition of anions/hydrated anions within the self-assemblies of simplest phenyl-based tris(oxyurea/thiourea) neutral ligands has been underexplored from 1995 and more challenging, mainly because of the lack of pi-acidic or electron-withdrawing substituents in aryl terminals, especially in the solid state. Herein, two simple tris(oxyurea) (L-1) and tris.thiourea) (L-2) electron-rich scaffolds are reported with comparatively less acidic terminal aromatic functionalization but still capable of trapping chair-shaped cyclic water hexamer within the infrequent fluoride encapsulated hexameric L-1 core as well as divalent carbonate anion encapsulated dimeric capsular cage of L-2 via hydroxide ion induced aerial CO2 fixation. Moreover, L-1 shows large dihydrogen phosphate dimer [(H2PO4-)(2)] bound neutral dimeric pseudo-capsular assembly, while the thiourea analogue L-2 exhibits chloride and acetate bound unimolecular capsular assembly and divalent sulfate bound dimeric cage via hydrogen-bonding activated proton transfer reaction.
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