Promising Ultraviolet Absorbers——Novel Guanine Analogs Having Significantly Improved Ultraviolet Absorption Capacity and Dissipating the Energy of Absorbed Photons by Nonradiative Decay Mechanism

摘要

Structural properties of nucleobase underlie their ultrafast excited-state dynamics and low fluorescence quantum yields,which cause effectively nonradiative decay process and render them like sunscreens.Thus,eight guanine analogs[N-2-(2'-nitrobenzoyl)-guanine,N-2-(3'-nitrobenzoyl)-guanine,N-2-(4'-nitrobenzoyl)-guanine,N-2-(2'-hydroxybenzoyl)-guanine,N-2-(4'-methoxylbenzoyl)-guanine,N-2-(4'-chloricbenzoyl)-guanine,N-2-(4'-methylicbenzoyl)-guanine and N-2-(3',5'-dinitrobenzoyl)-guanine] with different substituted benzoyls,except N-2-(4'-chloricbenzoyl)-guanine,were newly synthesized.In contrast with guanine,they exhibit wider ultraviolet absorbent range,higher molar extinction coefficient and lower fluorescence intensity.