E. Brunet et al., A simple polyheterotopic molecular receptor derived from bispyrazolylmethane showing ambivalent allosteric cooperation of zinc(II), EUR J ORG C, (10), 2000, pp. 1913-1922
The preparation of compounds 1-4 as simple systems to display allostery is
described. Transport experiments (bulk liquid membrane) of ammonium cations
in the presence or absence of ZnI2 in the receiving and donor phases evide
nced strong negative or positive allosteric effects of the metal towards am
monium complexation, which depended on the relative arrangement of crowns w
ith respect to the pyrazole nitrogens.