Photophysical properties of two novel guanidiniocarbonyl (I) and monocyclic guanidine (II)
tetraphenylporphyrins and their interaction with DNA were investigated by steady-state and time-resolved
absorption and emission spectroscopies. I stays predominantly monomeric in aqueous solutions. It produces
singlet oxygen with high quantum yield (ΦΔ=0.67) that is typical for monomeric porphyrins. The electronic
absorption spectra of I are not influenced by interaction with DNA. This is in contrast with monomeric tetratolylporphyrins
bearing phosphonium,ammonium and pyridinium groups where the formation of stable
complexes with DNA is accompanied by a characteristic red shift of the Soret band. II extensively forms Hand
J-aggregates,which do not produce singlet oxygen (ΦΔ<0.01). In the presence of DNA only a small
fraction of II remains in monomeric form that is bound to DNA exterior.
