Abstract
Abstract The cadmium(53P1)-photosensitized luminescence of some aliphatic diamines was studied by a steady-illumination method at temperatures between 230 and 330°C. It was found that 1,2-ethylenediamine, N,N,N′,N′-tetramethyl-1,2-ethylenediamine, 1,3-propanediamine, and N,N,N′,N′-tetramethyl-1,3-propanediamine have two emission bands (wavelengths at the peaks of these bands are about 450 and 550 nm), while N,N,N′,N′-tetramethylmethanediamine, N,N′-dimethylpiperazine, and triethylenediamine have only a short-wavelength band. From the temperature and pressure dependences of the emission intensities of the two bands, it had been concluded previously that these bands could be assigned to two kinds of 1 : 1 exciplexes between an excited cadmium atom and a diamine molecule. From the temperature dependence of the equilibrium constants between the two exciplexes which had been obtained from the ratio of the emission intensities of the two bands, the enthalpy and entropy changes of the equilibrium were evaluated. The cyclic exciplexes assigned to the long-wavelength band have smaller enthalpies and entropies than do the noncyclic exciplexes assigned to the short-wavelength band.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call