Studies of Some Hindered 2,2′-Bithienyls and 3,3′-Bridged 2,2′-Bithienyls With Special Reference to Their Uv Spectra and Oxidation Potentials

Some hindered bithienyl derivatives have been synthesized by cross-coupling reaction of Grignard reagents using NiCl2(dppp)(dppp = Ph2PCH2CH2CH2PPh2) or by reductive dimerization in the presence of Zn/NiCl2(PPh3)2. Their UV spectra and oxidation potentials are discussed in terms of their coplanarity and of the inductive effect of the substituent.