Photoswitching of the magnetic interaction between a copper(II) ion and a nitroxide radical by using a photochromic spin coupler.
Photoswitching of the magnetic interaction between a copper(II) ion and a nitroxide radical by using a photochromic spin coupler.
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DOI：
10.1002/chem.200305154
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发表时间：
2003-11
期刊：
影响因子：
--
通讯作者：
K. Takayama;K. Matsuda;M. Irie
中科院分区：
文献类型：
--
作者：
K. Takayama;K. Matsuda;M. Irie
用ESR研究了二芳基乙烯金属配合物对铜离子与硝酰基自由基分子内自旋交换相互作用的光开关效应。合成了一种含1，10-菲咯啉环和硝酰基氮氧自由基的二芳基乙烯配体。在甲苯中混合二芳基乙烯配体与[Cu（hfac）（2）]（hfac=六氟乙酰丙酮）导致闭环异构体的吸收最大值由于络合而发生蓝移。ESR测量在甲苯中在室温下的开环异构体的Cu（II）配合物给出了一个光谱，这是一个叠加的光谱从氮氧自由基和Cu（II）。当样品用366 nm的光照射时，由于大的交换相互作用，在硝酰基自由基和Cu（II）之间出现了一个新的峰。这种ESR测量表明，自旋交换相互作用的大小改变了超过160倍的光照射。这是在二芳基乙烯体系中记录的最大的磁光开关现象。
Photoswitching of an intramolecular spin exchange interaction between a copper(II) ion and a nitroxyl radical by using a metal complex of diarylethene has been studied by means of ESR spectroscopy. As a coordination ligand, a diarylethene with a 1,10-phenanthroline ring and nitronyl nitroxide radical was synthesized. Mixing the diarylethene ligand with [Cu(hfac)(2)] (hfac=hexafluoroacetylacetone) in toluene led to a hypsochromic shift of the absorption maxima of the closed-ring isomer due to complexation. ESR measurement in toluene at room temperature of the open-ring isomer of the Cu(II) complex gave a spectrum that is a superposition of the spectra from the nitroxide radical and Cu(II). When the sample was irradiated with 366 nm light, a new peak due to large exchange interaction appeared between those of the nitroxyl radical and Cu(II). This ESR measurement revealed that the magnitude of the spin exchange interaction was changed by more than 160-fold by photoirradiation. This is the largest magnetic photoswitching phenomenon recorded in diarylethene systems.