Alternative modes of conjugation in one-dimensional polymers

Abstract

Electronic delocalization may be achieved utilizing unconventional modes of conjugation between unsaturated centers. Spiroconjugation, through-bond coupling, and long-range through-space coupling have been explored as mechanisms for conjugation in one-dimensional semiconductors. Three prototypical systems are examined in order to shed light on the prospects for the actual exploitation of these modes of conjugation in electronically interesting polymers. The stabilizing or destabilizing influence of through-bond coupling and spiroconjugation is examined. A prevalent phosphorus chain system 1∞ [Px−5 ] (0<x<1) is analyzed as an example of an infinite ‘‘laticycle.’’ Through-space apex–apex interactions in this system have profound effects on the protonated derivative, 1∞ [P5H].