Intramolecular Hydrogen Bonding Effect on the Electron-Transfer Thermodynamics of a Series of o-Nitrobenzyl Alcohol Derivatives

From thermoelectrochemical experiments and electronicstructurecalculations of a series of nitrobenzyl alcohol derivatives, the effectof intramolecular hydrogen bonding (IHB) on the electron transferthermodynamics is discussed on a molecular basis. A linear correlationbetween formal reduction potential (E (1/2)) values and temperature was obtained for the temperature range from300 to 350 K. Estimated electron transfer entropy values (& UDelta;S)determined from this dependence and theenthalpy (& UDelta;& UDelta;H) changes relative to o-nitrobenzyl alcohol confirmed that the effect of the formationof IHB proved to be decisive in the charge-transfer thermodynamics.The possibility of intermolecular hydrogen bonding is further discussedupon comparing thermodynamic data among three different solvents.