Studies of polyphotochromic behaviour of supermolecules by NMR spectroscopy. Part 2. A bis-[3H]naphthopyran with a (Z)-ethenic bridge between each moiety
Studies of polyphotochromic behaviour of supermolecules by NMR spectroscopy. Part 2. A bis-[3H]naphthopyran with a (Z)-ethenic bridge between each moiety
复制标题
通过核磁共振波谱研究超分子的多光致变色行为。
DOI：
10.1039/b203014d
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发表时间：
2002
影响因子：
3.1
通讯作者：
G. Vermeersch
中科院分区：
文献类型：
--
作者：
J. Berthet;S. Delbaere;D. Levi;A. Samat;R. Guglielmetti;G. Vermeersch
用^1H和^19F NMR研究了一种新的双光致变色分子（CC-Z）的行为，该分子由两个萘并吡喃部分通过（Z）-乙烯双键连接而成。为了便于研究，还研究了萘并吡喃（Naphthopyran，NPH）和由萘并吡喃实体通过双键间隔基连接到甲氧基萘核（C-Z）的模型。首先，研究在低温（228 K）下进行，以提取表征光花菁的^1H和^19F NMR化学位移。此后，检查在环境温度下的行为，鉴定出（Z-E）异构化的主要反应以及分子内环化反应。还观察到环化形式的萘并吡喃实体的意想不到的热开放，导致光铁菁的不同立体异构体之间的平衡。
The behaviour of a new biphotochromic molecule ( CC–Z ), formed by two naphthopyran moieties linked through a ( Z )-ethenic double bond, has been studied by ^1H and ^19F NMR spectroscopy. To facilitate the investigations, a naphthopyran ( CHR ) and a model constituted by a naphthopyran entity linked through a double bond spacer to a methoxynaphthalene nucleus ( C–Z ) were also studied. At first, the studies were performed at low temperature (228 K) to extract the ^1H and ^19F NMR chemical shifts characterising photomerocyanines. Thereafter, the behaviour at ambient temperature was checked, identifying a major reaction of ( Z – E ) isomerisation as well as an intramolecular cyclisation reaction. An unexpected thermal opening of the naphthopyran entities in the cyclised form was also observed, leading to an equilibrium between the different stereoisomers of the photomerocyanines.