Kato Kenichi, Osuka Atsuhiro
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku Kyoto, 606-8502, Japan.
Angew Chem Int Ed Engl. 2019 Jun 17;58(25):8546-8550. doi: 10.1002/anie.201901939. Epub 2019 May 9.
meta- and para-Phenylenediamine-fused nickel(II) porphyrin dimers were synthesized by S Ar reaction of meso,β,β-trichloro nickel(II) porphyrin with meta- and para-phenylenediamines and subsequent Pd-catalyzed intramolecular C-H arylation. Their tetrachlorinated dication diradicals are very stable, allowing SQUID magnetometry and revealing clear open-shell characters for both meta and para isomers with ferro- and anti-ferromagnetic interactions, respectively. The nitrogen analogue of Thiele's hydrocarbon usually displays predominant closed-shell nature but its hidden diradical characters increase either in a twisted conformation or upon insertion of an additional phenylene spacer. The observed distinct diradical nature of the para-congener indicates that diradical properties can be enhanced also by efficient spin delocalization.
通过间位、β、β-三氯镍（II）卟啉与间苯二胺和对苯二胺的S Ar反应以及随后的钯催化分子内C-H芳基化反应，合成了间位和对位苯二胺稠合的镍（II）卟啉二聚体。它们的四氯化二价双自由基非常稳定，这使得可以使用超导量子干涉仪磁力计进行测量，并分别揭示出间位和对位异构体具有铁磁和反铁磁相互作用的明显开壳特征。蒂勒烃的氮类似物通常表现出主要的闭壳性质，但其隐藏的双自由基特征在扭曲构象中或插入额外的亚苯基间隔基时会增加。对位同系物所观察到的明显双自由基性质表明，有效的自旋离域也可以增强双自由基性质。
