[Charge transfer complexes of nucleic acid purine bases with benzoquinone. Evidence that nucleic acid components are pi-donors].

The absorption bands of the charge transfer complexes between nucleic acid, purine components and some of their derivatives (9CH3--Ade, Ado, dAdo, pA, App, Guo, Gpp, Gppp, Cof, Hyp) as electron donors and p-benzoquinone as the acceptor were obtained by the differential method in water solution at 293 K. These bands lie in the range 330--430 nm and have all characteristic properties of the charge transfer bands. All points of the relationships between the energy corresponding to the charge transfer band maximum (hvct) and the donor ionization potential (Id) for the nucleic acid components and their derivatives fall on the same straight line for the pi-donors (the aromatic molecules), known from literature data, which differ markedly from the same straight line for n-donors (the alifatic amines), obtained in this work. It shows that the investigated nucleic acid components and their derivatives are the pi-donors in the charge transfer complexes with p-benzoquinone.