183007-01-4Relevant articles and documents
EPR investigations of β-deuteriated 5,5"-dimethyl-2,2':5',2"-terthiophenes
Engelmann, Guennar,Stoesser, Reinhard,Kossmehl, Gerhard,Jugelt, Werner,Welzel, Hans-Peter
, p. 2015 - 2020 (2007/10/03)
The unambiguous assignment of the β-hyperfine coupling constants of the radical cations of 5,5"-dimethyl-2,2':5',2"-terthiophene (11) has been achieved by EPR spectroscopic investigations of the deuteriated compounds 12, 13, and 14.The syntheses of these substances were achieved by cross-coupling following the Negishi and Kumada reaction starting from deuteriated derivatives of chloromethylated thiophene derivatives.The generation of the radical cations was carried out by electrochemical oxidation at a constant potential in the EPR spectrometr.In the presence of acidic compounds a D-H exchange at the β-positions of oligothiophenes was observed.The experimentally determined spin density distribution was rationalized by means of semiempirical quantum mechanical calculations (RHF-INDO-SP).Theoretical and experimental assignments are in good agreement.