Hydrogen Bonding in Anion Recognition: A Family of Versatile, Nonpreorganized Neutral and Acyclic Receptors.

摘要: The diamides and disulfonamides m-C6H4(CONHAr)2 (Ar = Ph, 1; p-n-BuC6H4, 2, 2,4,6-Me3C6H2, 3), m-C6H4(SO2NHPh)2, 4, 2,6-C6H3N(CONHPh)2, 5, readily synthesized on a multigram scale, bind strongly to halides acetate in organic solvents with Ka's as high 6.1 × 104 (NMR spectroscopy). binding stoichiometry is 1:1 solution for all cases except the 4·F- 4·OAc- complexes, where both 1:2 stoichiometries were found. association constants CD2Cl2 (1H NMR) follow trend Cl- > Br- I- receptors. F- OAc- may be stronger or weaker than depending nature of receptor. presence pyridine nitrogen 5 more rigid amide 1−3 vs less sulfonamide structure 4 increases selectivity smaller anions. enthalpy entropy formation 2·Cl- ΔH −31 kJ/mol; ΔS −23 J/(mol·K) (VT-NMR). X-ray [PPh4]2[1·Br][Br]·CH2Cl2, shows complexation via two N−H···Br- hydr...