Design、Synthesis and Property of Bifunctional Photochromic Spirooxazine Molecule
|School||Institute of Physical and Chemical Technology|
|Keywords||Photochromism Spirooxazine Azobenzene TMHPO Bifunctional|
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, especially in optical information storage.In this thesis, we designed and synthesized two series compounds by linking spirooxazine with 4-hydroxy-tetramethyl-1-piperidinylox (TMHPO) and Azobenzene. The novel results are list as follows:1. Two series compounds have been synthesized. 1. Spiroxazine containing azo group. 2. Spiroxazine containing TMHPO group. Fifteen compounds have been synthesized, which have not been reported. The structures are as follows: 2. The photochromic mechanism of the bifunctional compound, spirooxazine containing azo group was investigated. It was found that in different solvent, the photochromic mechanism was different. In CH3CN, upon light irradiation with 355nm, only spirooxazine moiety was photoisomerized to the merocyanine form (PMC). In dibromopentane, it was found that the trans-cis photoisomerization of azobenzene moiety occurred through the pathway of excited triplet state.3. The compound having two photochromic group spirooxazine and azobenzene, which could be photoisomerized upon light irradiation with different wavelength independently. In CH3CN, upon light irradiation with 355nm, spirooxazine moiety was photoisomerized to the opened form while the trans-cis photoisomization of azobenzene moiety was not observed. Upon light irradiation with 532nm, the absorption of azobenzene moiety was different from that of before irradiation, while the photoisomerization of spirooxazine moiety didn’t occur. Based on that, we designed a molecular switch.4. The relationship between the photochromic and paramagnetic properties for bifunctional compound spirooxazine containing TMHPO, the compound SPO-TMHPO-1, has been studied. The bifunctional groups in the compound SPO-TMHPO-1 was linked by short chain, when irradiation with 254nm light, the ESR signal was reduced than that before irradiation. It could be having some applications.5. In PMMA, The light fatigue resistance of spiroxazines combined with TMHPO was studied. It was found that the light fatigue resistance of spiroxazines combined with TMHPO was better than that of the mixture of spirooxazine and TMHPO. And the light fatigue resistance of SPO-TMHPO-3 was better than that of SPO-TMHPO-7. It illuminated when linked by short chain, the interaction between the TMHPO and the spirooxazine was strong. When mixed together, the interaction between the TMHPO and the spirooxazine was faint.6. In PMMA, the thermal decay rate of the colored form of SPO-TMHPO-3、SPO-TMHPO-7 and the mixture of spirooxazine and TMHPO was investigated. It was found that the decay rate of the compound SPO-TMHPO-4, in which TMHPO was linked by short chain, was the slowest. And that of the compound SPO-TMHPO-7 was the fastest. That meaned that besides the interaction between the TMHPO and the spirooxazine, the free volume of PMMA also determined the thermal decay date. It was also found that the electron-donating groups in the 5-position of indoline moiety could stabilize the colored forms and then low the thermal decay date.