Synthesis, Fluorescence and DNA Photocleavage Activity of Phenothiazine-Corrole Gallium(III) Complexes

Abstract

Phenothiazine(PTZ)-corrole dyads 1-3 and their gallium(III) complexes 4-6 have been synthesized and characterized.The steady-state absorption and emission spectra and the time-resolved fluorescence decay profiles have been measured in toluene.The radiative and nonradiative rate constants have been obtained from the fluorescence quantum yields and monoexponential fluorescence lifetimes.The absorption spectra revealed that the gallium(III) corrole dyads exhibit stronger Soret bands and Q bands than free base corrole dyads.The fluorescence quantum yields of 1-3 are 0.156,0.134,and 0.139,and the radiative rate constants are 4.02×107,3.47×107,and 2.89×107 s-1,respectively.The fluorescence quantum yields of 4-6 are 0.502,0.443,and 0.494,and the radiative rate constants are 20.9×107,16.78×107,and 21.11×107 s-1,which are obviously higher than those of the corresponding free base corroles.The lifetimes of 4-6 are 2.40,2.64,and 2.34 ns,respectively,which are somewhat shorter than those of the corresponding free base corroles.Agarose gel electrophoresis shows that these gallium(III) corrole dyads could cleave supercoiled DNA(form I) to give nicked-circular DNA(form II) under irradiation.