All-aza smaragdyrin, a historic but elusive pentapyrrolic macrocycle, was successfully synthesized and characterized for the first time. Smaragdyrin BF 2 -complex 3 was smoothly synthesized by 2-fold S N Ar reaction of 1,9-dibromo-5-mesityldipyrrin with 5,10-dimesityltripyrrane. Treatment of 3 with methanesulfonic acid gave smaragdyrin 5 as a stable antiaromatic compound. Reduction of 5 with NaBH 4 under inert conditions gave smaragdyrin 6 as an aromatic congener, which was easily oxidized back to 5 in the air. Complex 3 was interconvertible with its 20?-congener 4 via oxidation with MnO 2 and reduction with NaBH 4 . Treatment of 3 or 4 with CuCl 2 in the presence of NaOAc gave hetero bimetal complex 8.
Bibliographical noteFunding Information:
The work is supported by the National Nature Science Foundation of China (Grant Nos. 21772036, 21602058, and 21705055), Science and Technology Planning Project of Hunan Province (2018TP1017), and Scientific Research Fund of Hunan Provincial Education Department (Grant No. 16A125). The work at Yonsei was supported by the Global Research Laboratory (GRL) Program funded by the Ministry of Science, ICT & Future, Korea (2013K1A1A2A020501 83). We thank Dr. Zier Yan (Rigaku Beijing corporation, China) for help in crystal analysis. We also thank Mr. Kyosuke Saito and Ko Furukawa for ESR measurements.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry