Helvetica Chimica Acta p. 1505 - 1519 (1994)
Update date:2022-08-05
Topics:
Bock, Hans
John, Andreas
Naether, Christian
Ruppert, Klaus
The Na+ and K+ radical-ion salts of 2,3-diphenylquinoxyline seem to be (according to a structural database search) among the first ones of N-heterocyclic radical anions in crystals.The one-electron reduction in aprotic 1,2-dimethoxyethan (DME) solution at metal mirrors and the crystallization under Ar have been preceded by cyclovoltammetric (CV) and ESR/ENDOR measurement.The first electron insertion at -1.63 V proves to be reversible, whereas the irreversible second step, which is accompained by an overcrossing of the CV line, can be rationalized by an "ECE-DISP" mechanism via a dianion redox disproportination.The ENDOR spectrum resolves four 1H couplings and allows to simulate the ESR spectrum including the 14N hyperfine splittings.Both dark-blue single crystals of the radical ion salts <2,3-diphenylquinoxaline.- Met+ (DME)> show unexpected similarities for Met+ = Na+, K+ despite the 36-pm difference in their ionic radii.The largest structural changes inflicted by the one-electron reduction of the N-heterocyclic molecule are observed in the vicinity of the N-centers bearing the highest effective nuclear charge.The DME-chelated metal cations coordinate at the N electron pairs and form Met+(DME)-bridged polymer chains of the radical anion, which are differently ondulated in the Na+ and K+ radical anion salts.The take-home lesson suggests that many more N-heterocyclic molecules might be analogously reduced under optimized conditions and isolated as single crystals.
View MoreContact:0833-5590788/5590338/5590055
Address:Victory in the town of Red Star Village,Mount Emei City,industrial concentration area storage processing logistics parkpark
Suzhou Howsine Biological Technology Co.,Ltd(expird)
website:http://www.howsine.com
Contact:86-512-67262751
Address:No 3,Weihua Road ,Suzhou Industrial Park ,Jiangsu ,China.
Contact:+86 21 5017 5386
Address:No 999,Jiangyue Rd, Minhang Dist ,201114,Shanghai ,China
Weifang Arylchem Chemical Co., LTD
Contact:86-536-5217866
Address:Development Zone, Shouguang, Shandong Province
Shanghai Run-Biotech Co., Ltd.
website:http://www.run-biotech.com
Contact:+86-21-31576854/57171705 / 57171706
Address:second floor, building 3, No.999, jiangyue Road, minghang District, Shanghai, China
Doi:10.1016/j.bmcl.2007.10.074
(2008)Doi:10.1016/S0040-4039(01)81355-1
(1984)Doi:10.1016/S0040-4039(00)78859-9
(1992)Doi:10.1016/j.tetlet.2006.09.157
(2006)Doi:10.1021/jm0607101
(2007)Doi:10.1021/jo00198a015
(1984)