Rao Yutao, Xu Ling, Zhou Mingbo, Yin Bangshao, Osuka Atsuhiro, Song Jianxin
Key Laboratory of Chemical Biology and Traditional Chinese Medicine, Ministry of Educational of China, Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, China.
Angew Chem Int Ed Engl. 2022 Aug 15;61(33):e202206899. doi: 10.1002/anie.202206899. Epub 2022 Jul 4.
The one-pot self-coupling reaction of 3-amino-5-bromo-BODIPY 9 under Buchwald-Hartwig amination conditions gave nitrogen-bridged cyclic BODIPY tetramer 10, pentamer 11, and hexamer 12. Oxidation of 10, 11, and 12 in the presence of alkali metal ions provided 13, 15, and 16, respectively, as the first examples of expanded azaporphyrins possessing more than six pyrrole rings. Curiously, the oxidation even in the absence of alkali metal ions gave the same complexes as a result of spontaneous complexation. 10-12 showed large association constants (10 -10 M ) with K and Na , but the spontaneous complexations were not observed, indicating the extremely high affinities of 13-16 toward alkali metal ions, which can be ascribed to the multiple and effective ion-dipole interaction of the alkali metal ion with the negatively polarized F atoms of the BF walls surrounding the cavity. Importantly, 13, 14, and 15 show diatropic ring currents as a result of global aromaticity.
在布赫瓦尔德-哈特维希胺化条件下，3-氨基-5-溴-BODIPY 9的一锅法自偶联反应得到了氮桥联环状BODIPY四聚体10、五聚体11和六聚体12。在碱金属离子存在下对10、11和12进行氧化，分别得到了13、15和16，它们是具有六个以上吡咯环的扩展氮杂卟啉的首例。奇怪的是，即使在没有碱金属离子的情况下进行氧化，由于自发络合也会得到相同的配合物。10-12与K⁺和Na⁺显示出较大的缔合常数（10⁴-10⁶ M⁻¹），但未观察到自发络合现象，这表明13-16对碱金属离子具有极高的亲和力，这可归因于碱金属离子与围绕空腔的BF壁中带负电的F原子之间的多重有效离子-偶极相互作用。重要的是，由于整体芳香性，13、14和15显示出抗磁环电流。
