%0 Journal Article %1 Lichtblau.1993 %A Lichtblau, Alexander %A Hausen, Hans Dieter %A Kaim, Wolfgang. %D 1993 %J Zeitschrift fuer Naturforschung, B: A Journal of Chemical Sciences %K butyldimethylsilyl butyldimethylsilylquinoxaline;electrochem butyldimethylsilylquinoxaline;mol butyldimethylsilylquinoxaline;quinoxaline crystal mol oxidn structure %N 6 %P 713--718 %R 10.1515/znb-1993-0603 %T First structural characterization of an easily oxidized derivative of 1,4-dihydroquinoxaline %V 48 %X The first crystal structure anal. of a 1,4-dihydroquinoxaline is described by example of the 1,4-bis(tert-butyldimethylsilyl) deriv. I. In the solid state, this mol. exhibits a nonplanar heterocycle with a dihedral angle of 156.3° along the N-N axis in the boat-shaped 8p electron ring system. The alkyl groups of the SiMe2CMe3 substituents are arranged so as to minimize steric repulsion. Despite the reduced p electron conjugation due to nonplanarity, the compd. is oxidized reversibly to an EPR detectable radical cation at -0.59 V vs. ferrocene in dichloromethane. However, the 2nd oxidn. to the fully arom. dication is electrochem. irreversible. A comparison with previously obtained results illustrates the structural flexibility of the nonarom. 1,4-dihydro-1,4-diazine ring system which is strongly affected by rather weak nonbonded interactions. on SciFinder(R)

@article{Lichtblau.1993, abstract = {The first crystal structure anal. of a 1,4-dihydroquinoxaline is described by example of the 1,4-bis(tert-butyldimethylsilyl) deriv. I. In the solid state, this mol. exhibits a nonplanar heterocycle with a dihedral angle of 156.3° along the N-N axis in the boat-shaped 8\textgreek{p} electron ring system. The alkyl groups of the SiMe2CMe3 substituents are arranged so as to minimize steric repulsion. Despite the reduced \textgreek{p} electron conjugation due to nonplanarity, the compd. is oxidized reversibly to an EPR detectable radical cation at -0.59 V vs. ferrocene in dichloromethane. However, the 2nd oxidn. to the fully arom. dication is electrochem. irreversible. A comparison with previously obtained results illustrates the structural flexibility of the nonarom. 1,4-dihydro-1,4-diazine ring system which is strongly affected by rather weak nonbonded interactions. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Lichtblau, Alexander and Hausen, Hans Dieter and Kaim, Wolfgang.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2e9fa6cc7c941d5d0eccf51dd033fbce0/huebleriac}, doi = {10.1515/znb-1993-0603}, interhash = {8b9bd7f966cb4c2f606187f2d1b1a5bc}, intrahash = {e9fa6cc7c941d5d0eccf51dd033fbce0}, issn = {0932-0776}, journal = {Zeitschrift fuer Naturforschung, B: A Journal of Chemical Sciences}, keywords = {butyldimethylsilyl butyldimethylsilylquinoxaline;electrochem butyldimethylsilylquinoxaline;mol butyldimethylsilylquinoxaline;quinoxaline crystal mol oxidn structure}, number = 6, pages = {713--718}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {First structural characterization of an easily oxidized derivative of 1,4-dihydroquinoxaline}, volume = 48, year = 1993 }