Synthesis And Properties Of Novel Photochromic Spiropyrans Having A Long Alkyl Side Chain

Photochromism is defined as a reversible phototransformation of a chemical species between two forms having different absorption spectra. Photochromism is a new scientific field born in 90's of twentieth century. It is an interdispline field based on the research of chemistry,physics,materials and photoelectronic technology. During the last decade, organic photochromic compounds have increasingly attracted more attention and interest of chemists and engineers due to their potential applications in the areas of optical information storage,ophthalmic glasses,electronic display systems and optical switches.Recently, the researchs about photochromic compounds focused mainly on Schiff bases,azo-compounds,fulgides,diarylethenes,spiropyrans and spirooxazines. Among of them, spiropyrans are the most important and the most candidates for the application because of their very good thermally irreversible and fatigue-resistant photochromic performances. The main purpose of this thesis is to synthesize novel photochromic spiropyrans bearing more perfect photochromic performances by linking long chain substitutes to the simple traditional spiropyrans. Moreover, to investigate the photochromic properties of these novel spiropyran compounds.This thesis mainly consists of three parts:In the first part, a brief review of photochromism is provided, including the definition and photochromic mechanism of the photochromic compounds; the recent development about kinds of photochromic compounds; and the recent applications of photochromic compounds in optical information storage,photocontrol of bio-active moleculars,photochromic super-moleculars,defend and decorate materials and so on.The second part focused on the synthesis of photochromic spiropyrans. In this thesis, we designed and synthesized three series spiropyran compounds.1. A series of novel spiropyran compounds bearing long chain groups derived from long chains containing indoles and various of salicylaldehyde ramifications; 2. Novel spiropyran compounds containing amide groups; 3. Novel spiropyran compounds containing long chains and barbiturate groups derived from aldehyde substituted spiropyrans and barbiturate. There are four new compounds that have not yet been reported. The structures of the spiropyran compounds are confirmed mainly by IR spectra,UV-Vis spectra,1H NMR and MS.In the third part, photochromic properties of the spiropyran compounds are investigated in many aspects mainly by UV-Vis spectra. It is shown that spiropyran compounds SP1,SP2,SP3,SP4,SP8 and SP9 reveal very good photochromic property in ethanol, while spiropyran compounds SP5,SP6 and SP7 reveal very good negtive photochromic property in ethanol. All the synthesized spiropyran compounds bear thermochromic property. Moreover, spiropyran compounds SP1,SP2,SP3,SP4,SP6,SP7,SP8 and SP9 are sensitive to pH. It is find that spiropyran compounds SP1,SP2,SP3,SP5,SP6,SP8 and SP9 reveal a negative solvatochromism in different solvents while SP4 and SP7 reveal a positive solvatochromism. Compare with the traditional spiropyran compounds, the spiropyrans bearing long chain groups are better at the aspects of dissolution,photochromism,fatigue-resistant and so on. In addition, we have also investigated the fluorescence property of the novel spiropyran compounds.