Spectroscopy of ionic and neutral forms of some substituted porphyrins in ground and excited states

The spectral-luminescent properties of solutions of tetraphenylporphyrin derivatives with different concentrations are investigated. The spectra of neutral and ionic forms are identified, and the quantum yields of usual and, in some cases, short-wavelength fluorescence from highly excited states are determined. The spectra of transient absorption from excited states arising during a few tens of nanoseconds are measured. A method of determining the quantum yield of triplet molecules is suggested and successively used. A mechanism of phototransformations of a compound in chloroform under laser excitation is elucidated.