Pulsradiolyse organischer Halogenverbindungen I. Nachweis kurzlebiger Charge‐Transfer Komplexe mit Chloratomen

In a solution of benzene in carbon tetrachloride a transient absorption in the visible part of the spectrum could be detected. It appears within less than 0.3 μs after the irradiation by a high‐energy electron pulse, and it can be shown to be due to the charge‐transfer complex between the chlorine atoms as electron acceptors and benzene molecules as electron donors. A variety of aromatic hydrocarbons also yield similar absorption bands in the visible. They show a linear correlation between the absorption energy and the ionisation potential of the aromatic molecules, which is typical for charge‐transfer complexes. A minimum value for the equilibrium constant of complex formation is given. The equilibrium is almost fully shifted to the complex side. An estimated G value for the charge‐transfer complex indicates that the complex is actually part of a main reaction in the radiation‐induced mechanism. The decay of the charge‐transfer complex is mostly pseudo‐first order with a half life of a few microseconds.