240. Syntheses of alkylphenanthrenes. Part II. Pimanthrene, 1 : 4 : 7-trimethylphenanthrene, retene, and 1 : 4-dimethyl-7-isopropylphen-anthrene
作者:Robert Downs Haworth、Barnet Mark Letsky、Cecil Robert Mavin
DOI:10.1039/jr9320001784
日期:——
Polymer-Bound Chiroptical Molecular Switches; Photochemical Modification of the Chirality of Thin Films
作者:Michiel L.C.M. Oosterling、Anne Marie Schoevaars、Henk J. Haitjema、Ben L. Feringa
DOI:10.1002/ijch.199600048
日期:——
Photobistable chiral polymers were obtained by covalent attachment of inherentlydissymmetric 2-hydroxy-9-(7′methyl-1′,2′,3′,4′-tetrahydrophenanthrene-4′-ylidene)-9H-thioxanthene to methacrylate copolymers with appropriate spacers. Upon irradiation at 300 nm the opticalactivity of thin films of these polymers could be altered.
Light-Driven Molecular Motors: Stepwise Thermal Helix Inversion during Unidirectional Rotation of Sterically Overcrowded Biphenanthrylidenes
作者:Matthijs K. J. ter Wiel、Richard A. van Delden、Auke Meetsma、Ben L. Feringa
DOI:10.1021/ja052201e
日期:2005.10.1
To investigate the unidirectional rotation of chiral overcrowded biphenanthrylidenes in more detail, the size of the substituent next to the double bond responsible for the unidirectionality of rotation was varied. The thermal and photochemical isomerization of three sterically overcrowded alkenes is described. The behavior of the biphenanthrylidenes with methyl and ethyl substituents is rather similar
为了更详细地研究手性过度拥挤的联亚芳基的单向旋转,改变了负责单向旋转的双键旁边的取代基的大小。描述了三种空间过度拥挤的烯烃的热和光化学异构化。具有甲基和乙基取代基的联亚芳基的行为相当相似,这些化合物围绕中心双键进行单向 360 度旋转,涉及两个光化学顺反异构化和两个热螺旋反转的四步序列。这两个真正的分子马达之间的唯一区别是一个小的熵效应,它导致乙基取代的分子马达旋转得稍微快一点。异丙基取代化合物的行为与其他两个显着不同。虽然不是所有不同的异丙基取代分子马达的异构体都被光谱检测到,但实验数据得出的结论是,这种化合物也可以被认为是一种分子马达,能够进行 360 度单向旋转。(1)H NMR 和 X 射线分析表明,在单向旋转中作为中间体的介观形式,证明热螺旋反转是一个逐步过程。