TY - DATA T1 - Recognition of Achiral and Chiral Ammonium Salts by Neutral Ditopic Receptors Based on Chiral Salen-UO2 Macrocycles PY - 2010/03/05 AU - Maria E. Amato AU - Francesco P. Ballistreri AU - Salvatore Gentile AU - Andrea Pappalardo AU - Gaetano A. Tomaselli AU - Rosa M. Toscano UR - https://acs.figshare.com/articles/journal_contribution/Recognition_of_Achiral_and_Chiral_Ammonium_Salts_by_Neutral_Ditopic_Receptors_Based_on_Chiral_Salen_UO_sub_2_sub_Macrocycles/2786419 DO - 10.1021/jo902328y.s001 L4 - https://ndownloader.figshare.com/files/4480795 KW - phenyl rings KW - anion KW - Neutral Ditopic Receptors KW - Chiral Ammonium Salts KW - chiral diimine bridge KW - recognition KW - chiral quaternary ammonium salts KW - Lewis acidic uranyl site KW - MM KW - TBA KW - TMA KW - receptor KW - CH KW - cation KW - NMR KW - complex N2 - A mononuclear (M20) and a dinuclear (M40) uranyl chiral macrocyclic complex, incorporating both a salen unit containing two phenyl rings linked to a chiral diimine bridge and the (R)-BINOL unit, behaves as an efficient ditopic receptor for achiral and chiral quaternary ammonium salts. Binding affinities in chloroform solution have been measured for 1:1 complexes of many quaternary salts encompassing tetramethylammonium (TMA), tetraethylammonium (TEA), tetrabutylammonium (TBA), and acetylcholine (ACh), as well as trimethylanilinium (TriMAn), benzyltrimethylammonium (BnTriMA), (α-methylbenzyl)trimethylammonium and pyrrolidinium cations. The anion of the salt is bound by the hard Lewis acidic uranyl site, with an increasing binding efficiency on increasing the anion hardness (I− < Br− < Cl−), whereas CH−π or π−π attractions by binapthyl moiety, or the salicylaldehyde unit, or the phenyl rings of diimine bridge ensure the recognition of the cation partner. Optimized structures of receptor−anion−cation ternary complexes obtained by MM calculations are supported by 2D-ROESY NMR measurements. ER -