For the solid state investigations, the oligomer to be investigated was deposited onto a Pt-disk electrode (@ = 1 mm) by sublimation or by dipcoating the respective oligomer in dichloromethane. In this way, fully chargeable (iv ) homogenous layers of differing thickness could be prepared.
The amount of material employed was determined from the integral under the redox waves ( = charge). In the reduction of p-sexiphenyl the charge numbers of the redox steps could be derived unambiguously from the observed charge ratio of 2.1 for the first two redox steps (Table 1 b,c). In the case of quaterphenyl an experiment was carried out with a large electrode and a weighable amount of material; this gave a value of 2 for the charge number. A similar experiment with sexiphenyl confirmed the above described direct method for the quantitative measurement.
By reduction and oxidation of one and the same sample ofp-sexiphenyl it was confirmed that the integral under the first reduction wave is identical with that under the first oxidation wave (Ei = 1.65 V), i.e., two electrons per molecule are transferred in both cases.