共查询到18条相似文献,搜索用时 109 毫秒
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螺吡喃是一类重要的光致变色化合物.螺吡喃的正向光致变色是指在紫外光照下,螺吡喃分子的C—O键异裂,由闭环无色体(SP)可逆地变成开环有色体(MC).所形成的有色体可以在暗条件下热致褪色或在可见光照下褪成无色体(示意图1).它的逆向光致变色是指某一类螺... 相似文献
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光致变色螺吡喃化合物的合成及光致变色性质测定 总被引:3,自引:0,他引:3
光致变色螺吡喃化合物的合成及光致变色性质测定赵福群,周金渭,张复实,唐应武,宋心琦(清华大学化学系,北京100084)目前本科教学中涉及光化学的实验很少,学生对这方面的理性知识和感性知识知之甚少,而光化学是目前一个非常活跃的研究领域。有鉴于此,我们结... 相似文献
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一种含螺吡喃和肉桂酸酯双光功能基团的光致变色染料的合成与性能 总被引:8,自引:0,他引:8
合成了一种含有光致聚合肉桂酸酯基团的新型光致变色螺吡喃染料,研究其与普通螺吡喃染料在不同高分子材料中的光致变色和热退色过程(PMMA和PVCi).通过UV-Vis光谱、NMR谱和IR光谱研究了新型染料中的肉桂酸酯基团的光致聚合过程,考察了其对螺吡喃结构的光致变色显色体热稳定性的影响. 相似文献
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在环已烷和乙腈的稀溶液中测定了1,3,3-三甲基-6′-硝基螺[吲哚啉-2,2′[2H]-苯并吡喃]光致变色过程的纳秒、微秒激光闪光光解光谱。实验结果表明:闭环体A的C—O键异裂发生在闭环体的激发单线态~1A~*而成为顺式结构单线态~1X~*(螺C—O键已断开,但仍保持闭环体的结构)和~3X~*(~1X~*系间窜跃)。中间产物~1X~*在纳秒级时间内很快生成CT(charge-separation twist state),CT吸收峰位置(580nm)基本上不受溶剂极性的影响,这说明其不是反式、两性离子结构的部花菁B。三线态~3X~*在氮气饱和溶液中的消减途径有2个,一是经基态X生成部花菁B,又因~3X~*的分子结构更接近闭环体A,其同时释放能量回到基态闭环体A。氧气饱和的溶液中,三线态~3X~*被猝灭成为X,其主要产物是部花菁B。此时反式两性离子结构的部花菁B生成速度变快、吸收强度变大。产物CT在环己烷溶液中和部花菁B共同存在,而在极性溶剂乙腈中,其最后生成了稳定的两性离子结构体部花菁B。 相似文献
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研究了1-正-辛基-3,3-二甲基-吲哚啉-2,2′-螺-5′,6′-(2-溴-4-硝基-苯并)吡喃, 1-正-辛基-3,3-二甲基-吲哚啉-2,2′-螺-5′,6′-(4-硝基-苯并)吡喃, 1-正-辛基-3,3-二甲基-吲哚啉-2,2′-螺-5′,6′-(2,4-二硝基-苯并)吡喃及1-正-辛基-3,3-二甲基-吲哚啉-2,2′螺-5′6′-(2-氯-4-硝基-苯并)吡喃在环已烷和甲苯溶液中光致开环过程的瞬态吸收光谱。观察到具有较长寿命的中间体及聚集体的存在。初步提出异构化反应过程的机制中既包含有三重态过程, 也有单重态参与。 相似文献
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设计合成了几种新型螺吡喃化合物(SP), 采用1H NMR, IR 和MS 对其结构进行表征. 研究了目标产物的光致变色性能及其影响因素, 并对SP1 在高分子材料领域的应用作了初步研究. 结果表明: 苯并吡喃环连有强吸电子基时, 最大吸收峰红移; 1 位N原子上连有柔性长链基团时, 热褪色速率较慢; 采用紫外光照射目标产物不同时间, SP1 表现出较好的抗光疲劳性. 分别以SP1 为接枝组分和共混组分制备两种高分子材料SP-g-hPMMA 和SP-m-PMMA, 通过紫外光辐照动力学研究表明, SP-g-hPMMA 和SP-m-PMMA 均表现出比SP1 优异的光致变色性能, 且不影响PMMA 的机械性能. SP1 有望用于高分子光致变色材料领域. 相似文献
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为了改善螺吡喃的光致变色性能,提高这一系列化合物的耐疲劳度,在螺吡喃吲哚啉环的氮原子上通过短碳链引入含氮杂环基团,成功合成了1'-(3-N-杂环基丙基)-3',3'-二甲基-6-硝基螺[吲哚啉-2,2'(2H)苯并吡喃](4a~4f).这一系列新的化合物.用核磁共振氢谱、碳谱、红外光谱和元素分析对这些化合物进行结构表征.通过紫外吸收光谱研究化合物在不同溶液(乙醇、二氯甲烷和环己烷)中和不同高分子膜(PMMA和PVB)中的变色性质.进一步对化合物4a在不同溶液中的动力学性质,以及在PMMA膜和PVB膜中的热消色动力学性质进行了研究,拟合计算并比较了消色过程的动力学常数.最后,又将化合物4a和不含含氮杂环的螺吡喃母体进行比较,发现耐疲劳度有很大提高. 相似文献
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IntroductionDiscoveryofthephotochromicreactionsofspiropy ransbyFischerandHirshberg1in 195 2andHirshberg’sideaofusingthephenomenonfora“photochemicalerasablememory”2 initiatedactiveresearchonpho tochromism .Numerousotherapplicationsbasedonre versiblecolorando… 相似文献
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Photochromic spiropyran molecules were embedded in electrospun polymer microfibers. Electrospinning of a clear viscous chloroform solution containing a spiropyran and a matrix polymer, such as polystyrene and polyethylene oxide, affords polymer microfibers that are photoswitchable. Photomasked, 365 nm UV irradiation of the microfibers results in the generation of patterned color images owing to the selective transformation of the spiropyran molecules from their ring‐closed SP to ring‐opened MC form. The UV‐irradiated areas display brilliant red fluorescence, which changes to green fluorescence upon prolonged irradiation.
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A series of spiropyrans with a polyaromatic or heteroaromatic pendant was synthesized conveniently.Their photochromic behaviors were investigated with the aid of absorption spectral measurements.The results indicated that the compounds with the same parent spiropyran but different aromatic pendant show significantly different photochromic properties.This may be due to the π-π orbital interaction between the polyaromatic pendant and the open photomerocyanine form of spiropyran.The results obtained are very useful in the molecule design area. 相似文献
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In situ photochromic process in the monolayer of aphotochromic spiropyran derivative without long alkyl chain,was investigated.The photochromism at the air/water interface under differnet surface pressures was studied by surface pressure-area isotherms,surface pressure-time curves,area-time curves and Brewster angle microscopy.Both forms of the compound were found to form monolayers at the air/water interface althouhg it does not have long alkyl chain.A large area expansion in the monolayer corresponding to a zreo^th order reaction was found at the initial stage of the UV light irradiation.A series of dynamic investigations revealed that at high pressure after phase transition in the monolayer,the surface pressure changes greatly umder alternative irradiation of UV and visible light.An obvious morphological change accompanying with the photochromism was observed in situ. 相似文献
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Clara Brieke Prof. Dr. Alexander Heckel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15726-15734
A new design is presented for the incorporation of spiropyran photoswitches into nucleic acids by oligonucleotide solid phase synthesis. This design enables interaction of the 6‐nitrospirobenzopyran (NitroBIPS) photoswitch with the adjacent nucleobases and leaves the photochemical properties of NitroBIPS intact. UV/Vis spectroscopy and HPLC revealed that NitroBIPS incorporated into DNA consists of up to 40 % merocyanine in its thermal equilibrium and undergoes reversible switching between the photoisomeric spiropyran (SP) and merocyanin (MC) state by alternating excitation using visible light or heat for at least fifteen switching cycles. Exchanging the chromene part of NitroBIPS on the DNA level gives access to differently substituted spiropyran derivatives allowing the screening for spiropyrans with suitable properties in a straightforward manner. Thus, by incorporating the highly hydrolysis‐stable pyrido‐spiropyran derivative PyBIPS pure light‐triggered reversible switching of a spiropyran in DNA has been realized for the first time. Therefore, this design represents a new useful platform for investigating the photochromic behavior of different spiropyran photoswitches in a nucleic acid environment and for using spiropyrans to induce light‐ or heat‐triggered changes in conformations or in fluorescence quenching properties of oligonucleotides. 相似文献
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Natalia L. Zaichenko Tatyana M. Valova Olga V. Venidiktova Alexander V. Lyubimov Andrey I. Shienok Liubov S. Koltsova Anton O. Ayt Galina V. Lyubimova Leonid D. Popov Valery A. Barachevsky 《Molecules (Basel, Switzerland)》2021,26(22)
Spectral-luminescence properties of a hybrid compound containing a coumarin-type spiropyran and an azomethinocoumarin fragment in toluene-acetonitrile solution in the presence of Li+, Ca2+, Zn2+ and Mg2+ ions are reported. Two excited state proton transfers can occur in the hybrid compound—the transfer of a proton from the OH group of the 7-hydroxy coumarin tautomer to the N atom of the C=N bond of the azomethine fragment leading to green ESIPT fluorescence with a maximum at 540 nm and from the OH group of the 7-hydroxy coumarin tautomer to the carbonyl group of the pyrone chromophore, which leads to the formation of the 2-hydroxyl-tautomer T of coumarin with blue fluorescence with a maximum at 475 nm. Dependence of these excited state proton transfers on the metal nature and irradiation with an external UV source is discussed. 相似文献