Synthesis, spectral, luminescence and photochemical properties of the chlorin е6 tricationic derivative with trimethylammonio groups

Abstract

The synthesis, spectral and luminescence properties of 3(1),3(2)-bis(N’,N’’,N’’’-trimethylaminomethyl iodide) chlorin е6 13(1)-(N’,N’,N’’’-trimethylammonioethyl iodide)amide-15(2),17(3)-dimethyl ester (1), and its photochemical reactions with molecular oxygen in pyridine are described. The absorbance of comp. 1 with molar absorption coefficient equal to 5.8∙104 M-1·cm-1 at 661 nm first band maximum is typical for chlorin e6 compounds family. In the light in pyridine solutions saturated with air oxygen, comp. 1 showed the fluorescence with maximum at 667 nm and quantum yield of 0.13 as well as the1O2 luminescence with quantum yield of 0.59. The inhibition method by hydroquinone of 1 photooxidation the role of the reaction with1O2 was confirmed and its contribution of 30 % in this process was detected. The last result is explained by the competitive chemical interaction between 1 excited triplet molecules and O2. The rate constant of the second order reaction between 1 and1O2 was determined to be 2.0∙104 M-1∙s-1.