S,C,C- and O,C,C-Bridged Triarylamines and Their Persistent Radical Cations
S,C,C- and O,C,C-Bridged Triarylamines and Their Persistent Radical Cations
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S,C,C-和O,C,C-桥三芳胺及其持久自由基阳离子
DOI：
10.1021/acs.joc.1c00969
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发表时间：
2021
期刊：
影响因子：
3.6
通讯作者：
Shin-ichiro Kato
中科院分区：
文献类型：
--
作者：
Shunpei Kataoka;Shuichi Suzuki;Yoshihito Shiota;Kazunari Yoshizawa;Taisuke Matsumoto;Motoko S. Asano;Toshitada Yoshihara;Chitoshi Kitamura;Shin-ichiro Kato
本工作报道了结构受限的S，C，C-和O，C，C-桥连的三芳胺衍生物及其持久自由基阳离子的合成、晶体结构和电子性质。通过简单的合成方法得到了O，C，C-桥连的三苯胺和二萘基苯胺。类似于先前报道的S，C，C-桥接的三苯胺，O，C，C-桥接的三芳基胺容易被氧化，以提供相应的自由基阳离子，这是作为六氯锑酸盐获得。X-射线晶体学分析表明，这些O，C，C-桥连的三芳基胺自由基阳离子，这是平面三芳基胺自由基阳离子的家庭没有取代基的芳基环上的新成员几乎平面结构。的S，C，C-和O，C，C-桥接的三芳基胺自由基阳离子的电子性质的详细调查表明，自旋和正电荷是充分离域的平面三芳基胺支架。结果为桥接单元的影响提供了以下见解（硫对氧）和二苯并成环对桥联三芳胺自由基阳离子自旋离域的影响：（1）硫桥相对于氧桥有效地降低了氮原子上的自旋密度;二苯并成环作用导致氧原子上的自旋密度适度降低，而不是氮原子上的自旋密度。
This work reports the synthesis, crystal structures, and electronic properties of structurally constrained S,C,C- and O,C,C-bridged triarylamine derivatives and their persistent radical cations. O,C,C-Bridged triphenylamines and a dinaphthylphenylamine were obtained through a straightforward synthetic protocol. Similar to a previously reported S,C,C-bridged triphenylamine, the O,C,C-bridged triarylamines were easily oxidized to afford the corresponding radical cations, which were obtained as hexachloroantimonate salts. X-ray crystallographic analyses showed almost planar structures for these O,C,C-bridged triarylamine radical cations, which represent new members of the family of planar triarylamine radical cations without substituents on the aryl rings. Detailed investigations of the electronic properties of the S,C,C- and O,C,C-bridged triarylamine radical cations demonstrated that the spin and positive charge are sufficiently delocalized over the planar triarylamine scaffolds. The results provide the following insights into the effects of the bridging unit (sulfur vs oxygen) and the dibenzo-annulation on the spin delocalization in the bridged triarylamine radical cations: (1) An effective decrease of the spin density on the nitrogen atom is observed for the sulfur bridge relative to the oxygen bridge; and (2) a moderate decrease of the spin density on the oxygen atom rather than the nitrogen atom is induced by the dibenzo-annulation.