Poly(para-phenylene) with the end structure of (formula presented) provides nearly zero band gaps in long chains with (formula presented)

It was demonstrated from the molecular orbital theory that (formula presented) in which at least one H atom on the end of poly(para-phenylene) (PPP) is replaced by (formula presented) group of the chain, provides nearly zero band gaps in the long chains with (formula presented) This behavior was explained by the band overlap leading to metallic characteristics from the perspective of the intermolecular interaction between ethylene units in the oligomer.