Inclusion abilities of thiacalix- and calixarenetetrasulfonate (3 and 4) towards mono-substituted benzenes were investigated in neutral aqueous solution. In general, the hosts regioselectivity encapsulated the guests from the aromatic moiety except the complexation of toluene by 4, in which the guest penetrated from either the aromatic or the methyl group. Stabilities of the inclusion complexes increased with the electron-withdrawing ability of the7 substitutuent on the guest, suggesting π-π electronic interaction between the host and guest. In spite of the lower electron density of the aromatic ring, thiacalixarene 3 showed higher inclusion ability than calixarene 4, suggesting that the size rather than the electron density of the calix framework is a more important factor in determining the inclusion ability.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry