Excited States of Chiral Pyrazines
Absorption spectroscopy is one of the most used methods for investigation of the excited states of molecules. Although it is an extremely powerful tool for this purpose, it nevertheless has the disadvantage that weak bands — at least when recorded in solution — are in general not clearly discernible if they appear close to a strong band. A combination of this “isotropic” absorption measurements with that of the Circular Dichroism (CD) can often be of great help; especially the utilization of the so-called “g-factor” has been advocated by MASON (2) but this is still very seldom done. We would like to show here hew this combination of UV- and CD-spectroscopy can be successfully used in assigning symmetry labels to four excited states of pyrazines. The preparative work, determination of the absolute configuration, and part of the CD-evidence has recently been published by us (3).
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References and Notes
- (1).Fellow of the A.-v.-Humboldt-Stiftung 1974/5 at Bochum. Permanent address: Central Chemical Research Institutes of the Hungarian Academy of Sciences, Budapest.Google Scholar
- (6).Badruddin, Thesis, Bochum (1975).Google Scholar
- (15).H. Smith and A.A. Hicks, Chem.Comnun. 1112 (1970).Google Scholar
- (20).G. Snatzke, Angew. Chemie, in preparation.Google Scholar