W. Peschke et Fp. Schmidtchen, INCREMENTAL RIGIDIFICATION OF A FOLDABLE ANION HOST - DOES IT HELP INGUEST BINDING, Tetrahedron letters, 36(29), 1995, pp. 5155-5158
In an effort to quantify the effect of freezing internal rotations in
foldable onion hosts we prepared compounds 11-14. In spite of their st
ructural similarity the complex stability in this series with squarate
anion in DMSO spanned about two powers of ten and gave no indication
for a dependence on host flexibility.