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DISIGN AND CONSTRUCTION OF ORGANIC FERROMAGNET AND THEIR CRYSTAL DESIGN.

有机铁磁体及其晶体设计的设计和构造。

基本信息

批准号：
06453037
负责人：
NAKAMURA Nobuo
金额：
$ 3.84万
依托单位：
HOSEI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

In order to achieve an organic ferromagnet, two approaches to it were adopted ; (i) intrarmolecular approach and (ii) intermolecular one.(i) Previous ESR studies on branched-chain hexa-and nonacarbenes, successfully generated photochemically at a cryogenic temperature from the corresponding diazo precursors, suggested their magnetic behaviors as spin-glass or super-paramagnetic. Though large scale preparations of the carbene precursors were carried out to get further insights into the phenomenon, preliminary experiments on an AC-SQUID instrument revealed that the instrumental sensitivity was quite disappointing under an extremely dilute condition which was definitely required for the carbene not to interact antiferromagnetically.The key step for the preparation of those carbene precursors was an amine-catalyzed cyclo-trimerization reaction of ethynyl ketones, whose mechanisms were determined by the use of substituted aryl ethynyl ketones to involve aryl 2-aminoethenyl ketones.Cyclic he … More xacarbene which might be assumed to have a partial skeleton of an ideal polycarbene with honycomb structure was successfully generated to show that the spin quantum number S is 6 as expected theoretically. This result together with those of isomeric branched-chain hexacarbenes clearly demonstrates that the spin multiplicity of the alternant hydrocarbon molecules is determined by the topological symmetry of the pi-bond sequence.(ii) As preliminary X-ray structural analysis on (3,5-dihydroxyphenyl) nitronyl nitroxide indicated the hydroxyl group to be effective in arranging the molecules two dimentionally, syntheses, magnetic observations, and x-ray crystallographic analyzes of several (hydroxynaphthyl) nitronyl nitroxide isomers were performed along with those of the corresponding (bromophenyl)- and (bromonaphthyl) nitronyl nitroxide radicals. It was found that some of these radicals showed ferromagnetic behaviors at extreme low temperatures. Further studies on these molecules are under way. Less

为了实现有机铁磁体，采用了两种方法；(i)分子内方法和（ii）分子间方法。(1)前人对支链六碳烷和非碳烷的ESR研究表明，从相应的重氮前驱体在低温下光化学合成的支链六碳烷和非碳烷具有自旋玻璃或超顺磁性。虽然为了进一步了解这一现象，进行了卡宾前体的大规模制备，但在AC-SQUID仪器上的初步实验表明，在极稀的条件下，仪器灵敏度相当令人失望，这是卡宾不发生反铁磁相互作用所必需的。羰基前驱体制备的关键步骤是胺催化乙基酮的环三聚化反应，其机理是用取代芳基乙基酮参与芳基2-氨基乙基酮。成功地合成了具有蜂窝状结构的理想聚碳酸酯的部分骨架，并证明了自旋量子数S为6。这一结果与同分异构体支链己烯的结果一起清楚地表明，交替烃类分子的自旋多重性是由pi键序列的拓扑对称性决定的。（ii）对（3,5-二羟基苯基）硝基氮氧化物进行了初步的x射线结构分析，结果表明羟基对分子的二维排列是有效的，因此对几种（羟基苯基）硝基氮氧化物异构体以及相应的（溴苯基）和（溴萘基）硝基氮氧化物自由基进行了合成、磁观察和x射线晶体学分析。发现其中一些自由基在极低温下表现出铁磁性。对这些分子的进一步研究正在进行中。少