The absorption maximum of D was 580 nm and was quite different from that of the corresponding 1, 4analogue A, A, 505 nm. This means that both terminal sites of the acyclic radical cation are electronically interacting with each other and the degree of the interaction seems to depend on the chain length. Introduction of two methyl substituents at C2 and C3 positions of A induces the destabilization, and the 1, 4-radical cation B is no longer ...
