权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study on the preparation and properties of polycyclic compounds bearing extremely bent benzene rings.

苯环极度弯曲多环化合物的制备及性能研究

基本信息

批准号：
04453018
负责人：
TSUJI Takashi
金额：
$ 4.35万
依托单位：
Hokkaido 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：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

1.Preparation of |1.1|paracyclophane and theoretical study on its structure and energetics. The preparation of |1.1|paracyclophane (2) via photochemical isomerization of bis (Dewar benzene) compound (1) was accomplished for the first time on the substituted derivative (R=CO_2Me) last year. To explore the chemistry of extremely strained cyclophanes further, unsubstituted 1a was prepared and 2a was successfully generated from 1a via its photochemical isomerization. According to theoretical calculations the interatomic distance between the opposing bridgehead carbons is exceptionally short at 2.3-2.4A and, thus, strong transannular interactions between the two aromatic rings in 2 is suggested. The calculations also suggest that removal of two electrons from 2a leads to electronically stabilized dication 2a^<2+> in which electronic charge is extensively delocalized and the interatomic distance mentioned above further diminishes to 2.05A,an unusually short interatomic distance for non-bonded carbon atoms. Investigation on the kinetic stabilization of 2 and the generation of 2^<2+> is now underway.Study on photochemical reactivities of Dewar benzenes 1.4-bridged with functionalized four-carbon-chain. Interested in a possibility that bridged Dewar benzene-|4|paracyclophane system may function as a photochemically driven molccular switching device. Dewar benzene derivatives bearing electron-withdrawing groups on the side chain were prepared and their photochemical behaviors were studied. Compounds 3b and 4a underwent photochemically reversible transformation into 5b and 6a, respectively, which exhibited characteristic UV/V is absorption spectra extending to 500nm. The photochemical reactivities of 3a and 4b were strikingly different from those of 3b and 4a, and their isomerization into the |4|paracyclophane structures could not be detected.

1.|1.1|对环番的合成及其结构和能级的理论研究去年首次实现了双(杜瓦苯)化合物(1)在取代衍生物(R=CO_2Me)上的光化学异构化制备|1.1|对环番(2)。为了进一步探索极端应变的环番化合物的化学结构，制备了未取代的1a，并成功地通过1a的光化学异构化生成了2a。根据理论计算，相对桥头碳之间的原子间距在2.3-2.4A之间非常短，因此，2中的两个芳环之间存在很强的跨环相互作用。计算还表明，从2a中移除两个电子导致电子稳定的2a^&lt；2+&gt；，其中电子被广泛离域，上述原子间距进一步减小到2.05A，这对于非键碳原子来说是一个异常短的原子间距。2的动力学稳定和生成2^-lt；2+&gt；的研究正在进行中。研究了官能化四碳链桥连的杜瓦苯的光化学反应活性。感兴趣的是，桥联杜瓦苯-对环番体系可能作为光化学驱动的分子开关器件发挥作用。合成了侧链含吸电子基团的杜瓦苯衍生物，并对其光化学行为进行了研究。化合物3b和4a分别在光化学上可逆转变为5b和6a，其特征的UV/VIS吸收光谱扩展到500 nm。3a和4b的光化学反应活性与3b和4a的明显不同，没有检测到它们异构化成|4|对环番结构。