| Abstract: | Tetrathiafulvalenes. XXII. Redox- and Spectroscopic Properties of Tetrathiafulvalenes (TTF) and Tetraselenafulvalenes (TSF) and their Mono- and Dications The polarographic oxidation potential of TTF is decreased by alkyl- and increased by aryl-substituents. The oxidation potentials of arylated TTF can be correlated with σ+-constants (σ 0,1). TSF are weaker donors than the respective TTF. Alkyl substitution at TTF causes a bathocromic shift and aryl substitution a hypsochromic shift of the longest wavelength absorption band. In the mono- and dications of TTF a bathochromic shift of this absorption band is observed by alkyl- as well as aryl-substituents which is especially pronounced, when the molecule is planar. |
