Solvent Tuning of the Optical Absorption and Fluorescence Properties of Meso-tetra(aryl) porphyrins and Their Dications With Weak and Strong Carboxylic Acids

摘要

abstract_textpThe solvent dependence of the photophysical properties of meso-tetra(aryl) porphyrins with electron-donating and electron-withdrawing meso substituents and their dications with CF3COOH and CH2ClCOOH has been studied. Dependence of the natural radiative lifetimes (tau(1), tau(2), tau(3)), non-radiative rate constant (k(nr)), fluorescence quantum yields (Phi(f)), stokes shifts and the intensity of the emission bands of the free base porphyrins and the dications on the solvent polarity and Lorentz-Lorenz function, Phi(n(2))= (n(2) -l)/(n(2) + 2) (n, refractive index) was investigated in details. Furthermore, the degree of configuration interaction (CI) between the excited states was evaluated from the f(Soret)/f(Q(0,0)) ratio. It was found that the optical absorption and fluorescence characteristics of the free base porphyrins and their diacids can be finely tuned by changing the solvent's polarity, even though no close correlation was observed between some of the optical properties and the solvent properties./p/abstract_text