Anion Recognition with Antimony(III) and Bismuth(III) Triaryl‐Based Pnictogen Bonding Receptors

The synthesis and characterisation of a library of acyclic antimony(III) and bismuth(III) triaryl pnictogen bonding (PnB) receptor systems are reported. In the first‐generation receptor series, quantitative (1)H NMR chloride titration experiments in THF solvent media reveal halide anion binding potency is intimately correlated with both the electronic‐withdrawing nature of the aryl‐ substituent and the polarisability of the PnB donor. Further extensive anion binding investigations with the most potent Sb‐ and Bi‐based PnB receptors: 1⋅Sb(2CF3) and 1⋅Bi(2CF3) , reveal novel selectivity profiles, both displaying Cl(−) selectivity relative to the heavier halides and, impressively, to a range of highly basic oxoanions. The synthesis and preliminary chloride anion binding studies of a series of novel tripodal tris‐proto‐triazole triaryl Sb(III) and Bi(III) mixed PnB‐HB receptor systems are also described. Whereas parent triphenyl Sb(III) and Bi(III) compounds are incapable of binding Cl(−) in THF solvent media, the PnB‐triazole HB host systems exhibit notable halide affinity.