Selectivity and Cooperativity in the Binding of Multiple Guests to a Pillar[5]arene-Crown Ether Fused Tricyclic Host

J Org Chem. 2015 Aug 21;80(16):7994-8000. doi: 10.1021/acs.joc.5b01038. Epub 2015 Aug 7.

Abstract

A novel tricylic host molecule 1 that consists of two pillar[5]arene units and a crown ether ring was found to selectively bind two kinds of guest molecules with different shapes, sizes, and electronic constitutions, namely 1,4-dicyanobutane G1 and paraquat G2, with its two macrocyclic subunits, to form a four-component complex 2G1⊂1⊃G2. An (1)H NMR study of stepwise bindings of G1 and G2 to host 1 in CDCl3/DMSO-d6 revealed that the strength of the association between complex 2G1⊂1 and guest G2 was only one-fourth of that between free 1 and G2, demonstrating a negative heterotropic cooperativity of G1 in the binding of G2 to host 1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Calixarenes
  • Crown Ethers / chemistry*
  • Crystallography, X-Ray
  • Macrocyclic Compounds / chemical synthesis*
  • Macrocyclic Compounds / chemistry
  • Models, Molecular
  • Molecular Conformation
  • Quaternary Ammonium Compounds / chemistry*

Substances

  • Crown Ethers
  • Macrocyclic Compounds
  • Quaternary Ammonium Compounds
  • pillar(5)arene
  • Calixarenes