Temperature Dependence of Excited Singlet S1-State Deactivation in Corrole Free Bases

NH-tautomerization in the lowest excited singlet S1-state of 5,10-mesityl-15-(2,6-dichloropyrimidinyl)corrole free base was studied in solution at 278–318 K and shown to be the dominant deactivation channel for electronic excitation energy of its short-wavelength tautomer T2. NH-tautomerization was found to cause significant changes in the deactivation quantum yields of electronic excitation energy of this tautomer as a function of temperature. About 90% of the electronic excitation energy of corrole molecules accumulated in the singlet S1-state of long-wavelength tautomer T1 after phototautomerization if the temperature was increased to 318 K.