新型中位取代七甲川菁染料的合成及光稳定性研究

本文合成了两种新型中位取代近红外七甲川菁染料,采用核磁1 HN-MR和HRMS质谱对其结构进行了表征.并测试了染料在不同溶剂中的吸收光谱和荧光发射光谱性质.染料3b、3c在甲醇中的最大吸收波长和最大荧光发射波长分别为677/790nm和647/786nm,斯托克斯位移分别为113 nm、139nm.经过光降解实验测试得到3种染料3a—3c在乙醇中的光降解速率常数分别为1.21×10-3 mol/min、1.81×10-3 mol/min和2.14×10-3 mol/min.循环伏安法测得染料3a—3c的氧化电位分别在0.729V、0.624V和0.598V.光降解实验表明:七甲川菁染料中位亚甲基链上吸电基取代增强染料光稳定性,供电基取代减弱染料的光稳定性;供-吸电子能力强弱决定了染料的光稳定性强弱;同时中位氯原子取代与共轭链上的氢键作用有利于染料的稳定性增强,中位氮原子取代无法形成很好的氢键作用,不利于染料稳定性的提高.

Synthesis, Characterization and Spectral Properties of Novel Meso-Substituted Heptamethine Cyanine Dye

Two novel meso-substituted heptamethine cyanine dyes were prepared and characterized by 1HNMR and HRMS spectra.The absorption and emission spectral properties in different solvents were studied.The maxima of the absorption and fluorescent spectra of the dyes 3b and 3c were at 677/790 nm and 647/786 nm in methanol respectively with larger stokes shifts of 113 nm and 139 nm.The photo-degradation reaction showed that the rate constants for the three dyes 3a—3c were 1.21×10-3 mol/min,1.81×10-3 mol/min and 2.14×10-3 mol/min respectively.Cyclic voltammetry showed that the oxidative potentials for 3a—3c were 0.729 V,0.624 V and 0.598 V respectively.The experiment of photodegradation showed that electron-withdrawing group on methine chain of heptamethine cyanine dye enhanced the photostability and electron-donating group on methine chain decreased the photostability of the dyes.The ability of donating and withdrawing affected the photostability of the dyes.The hydrogen bond on substituted atom on methine chain was favor for enhancing the photostability of the dyes.And hydrogen bond of chlorine atom on methine chain was in favor of enhancing the photostability of the dyes.But nitrogen atom on methine chain can not form hydrogen bond and not helpful for the photostability of the dyes.