Abstract: The interaction of 1,4-benzodiazepin-2-ones, the sedatives and muscle relaxants in medicine, with tetracyanoethylene or potassium p-methylphenoxide can form charge transfer complexes respectively. Using spectrophotometric method, the electron affinity(E_A) and the ionizaton potential (I_p) of the title compounds are calculated with the energy of electron transfer hv_CT. The thermodynam-ic constants(K, △H, △S) of the complexes are determined as well. The results show that 1,4-benzo-diazepin-2-ones can not only act as the charge acceptors but also as the charge donors. The hv_CT or △Hvs Hammett substituent constant σ at position 7 of the molecule gives a linear relationship.

Key words: 1,4-Benzodiazepin-2-ones, Charge transfer complex, Electron affinity, Ionization poten-tial