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 reversibility of the process was tested by quenching with molecular oxygen. The reduction of 1 with all three metals yields the corresponding tetraanion salt 1(4-)/4M(+). Compound 2 was reduced reversibly with potassium and sodium only, while compound 3 underwent decomposition. According to the UV-VIS spectra and the electrochemical results, the tetraanion species is formed via a stepwise four-electron transfer process. A strong effect of the cyclophane hub on the charge distribution vis a vis a relevant model system is demonstrated.