Fluorescence spectra of asymmetric diamines having primary and tertiary amino groups

Broad and asymmetric emission spectra were obtained with some saturated dia mines which have a primary and a tertiary amino group in cyclohexane, dieth yl ether and tetrahydrofuran. These spectra were resolved into three compon ent bands. The shortest- and longest-wavelength bands were assigned to an e xcited tertiary amino group moiety and an exciplex formed between the excit ed tertiary amino group and the ground-state primary amino group. The middl e-wavelength band was assigned to an excited primary amino group moiety for med through the exciplex. The enthalpy changes among three emitters were es timated from the temperature dependences of the intensity ratios of the emi ssion bands. The solvent effect on the emission bands and the enthalpy chan ges are discussed.