CHARGED CYCLOPHANES WITH EXTENDED CONJUGATION - THE EFFECT OF THE CYCLOPHANE HUB ON THE CHARGE-DISTRIBUTION

Compounds 1, 2 and 3 were chemically reduced with lithium, sodium and potassium metals in [H-2(8)]THF at 220 K. In each case the reversibili ty of the process was tested by quenching with molecular oxygen. The r eduction of 1 with all three metals yields the corresponding tetraanio n salt 1(4-)/4M(+). Compound 2 was reduced reversibly with potassium a nd sodium only, while compound 3 underwent decomposition. According to the UV-VIS spectra and the electrochemical results, the tetraanion sp ecies is formed via a stepwise four-electron transfer process. A stron g effect of the cyclophane hub on the charge distribution vis a vis a relevant model system is demonstrated.