Effects of Electron Donors on the Photodecomposition of Menadione in Aqueous Solution. I. The Interaction between Electron Donors and Menadione in Aqueous Solution.

Among nine pharmaceutical preparations, the values of parameters λh.o. and λl.e. representing the energy levels of the highest occupied molecular orbital and the lowest empty molecular orbital were obtained by a molecular orbital method, simple LCAO MO method of π-electrons. On the basis of these calculations, it was found that eight electron donors used formed the molecular complex with menadione in aqueous media. The free energy changes in the complex formation tend to be increased by the addition of better eletron donors. As a result, it was suggested that the driving force of the complex formation would be due to charge transfer force.