P. Goralski et al., THE HYDROGEN-BONDING OF ALCOHOLS, CHOLESTEROL AND PHENOLS WITH CYANATE AND AZIDE IONS, Perkin transactions. 2, (11), 1994, pp. 2337-2340
The hydrogen bonding between ROH hydrogen bond donors (alcohols, chole
sterol and phenols) and the cyanate and azide anions has been investig
ated in CCl4 solution by FTIR spectroscopy. Equilibrium constants K-a
and enthalpies of complex formation, have been determined by using the
intensity of the antisymmetric vibration nu(a)(X) of the uncomplexed
anions X(-). The nu(a)(X) frequency shifts in the NBu(4)X...HOR comple
xes have also been measured. The cyanate and azide anions are found to
be the strongest hydrogen bond accepters ever reported. The correlati
ons between the frequency shifts and log K-a values reveal a strong in
fluence of steric effects on association constants. The very strong ba
sicity of the cyanate ion allows a significant discrimination of the h
ydrogen bond acidity of the three classes of alcohol.