Conjugated hetero-TCNQs

As mentioned earlier, 1 shows lower reduction potentials than TCNQ, reflecting the lower aromaticity of thiophene than benzene. In cyclic voltammetry, the first half-wave reduction potentials of 27 and 30 are further lower than that of 1 (Table 4.1). However, gaps between the first and second reduction waves become smaller with separation of the two dicyanomethylene groups as expected, demonstrating effective reduction of on-site coulombic repulsion in the dianionic states. In particular, the second wave of 30 coalesces into the first one as a result of minimization of on-site coulombic repulsion. The conjugated hetero-TCNQs 27 and 30 like 1 form non-ionic complexes with TTF, but interestingly their electrical conductivities are... 

---