کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
27466 | 44024 | 2011 | 5 صفحه PDF | دانلود رایگان |
Zinc chlorophyll derivatives possessing various substituents at the 3- and 13-positions were cleaved at the C19–C20 bond upon irradiation of an oxygen-saturated dichloromethane solution with visible light. The resulting photooxidation products were zinc complexes of linear tetrapyrroles which showed longer wavelength absorption bands in the near-infrared region than the visible Qy bands of the corresponding cyclic tetrapyrroles as the starting materials. Electron-withdrawing C13-substituents of the linear tetrapyrroles shifted the longest absorption maxima bathochromically, as observed in the cyclic tetrapyrroles. In contrast, more electron-withdrawing C3-substituents of the linear tetrapyrroles gave more hypsochromically shifted redmost maxima, which was the reverse of the substitution effect of the cyclic tetrapyrroles.
► Photooxidative cleavages of zinc chlorophyll derivatives.
► Preparation of linear tetrapyrroles possessing various C3- and C13-substituents.
► Usual bathochromic shifts of redmost maxima by electron-withdrawing C13-substituents.
► Novel hypsochromic shifts of redmost maxima by electron-withdrawing C3-substituents.
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 219, Issues 2–3, 15 April 2011, Pages 250–254