POTENTIAL PHOTOSENSITIZERS FOR PHOTODYNAMIC TUMOR THERAPY—I. PHOTOPHYSICAL PROPERTIES OF TWO CHLORIN DERIVATIVES

Abstract

Abstract— Photophysical properties of two chlorin type molecules (CHLI) and (CHLII) were investigated in different solvents. Quantum yields of fluorescence φ F of S, → T, intersystem crossing φ T , and of singlet oxygen ( 1 Δ g ) formation φ Δ , as well as the Stern‐Volmer constants for the quenching of the S, states by oxygen and the bimolecular rate constants of quenching of 1 Δ g by the chlorins were measured. The values of φ T and φ Λ can be given as 0.57 and 0.58 for CHLI and 0.69 and 0.58 for CHLII. The values of the fluorescence quantum yields, the strong absorption of the chlorins in the red (Λ > 630 nm) and the high values of the quantum yields for 1 Δ g formation recommend the chlorin derivatives as potential markers and photosensitizers for tumor therapy.