Inclusion complex formation of p-nitrophenol and p-nitrophenolate with hydroxypropyl-beta-cyclodextrins

The interaction of the p-nitrophenol/p-nitrophenolate conjugate has been in vestigated with different 2-hydroxypropyl-beta-cyclodextrin hosts. The meas ured values for stability constants attain a maximum as a function of incre asing average degree of substitution. The quotients of constants, character izing the inclusion of p-nitrophenolate and p-nitrophenol, respectively, ar e decreased showing that the effect of London dispersion forces is greatly overshadowed by the hydroxypropylation.