Cross-conjugation

Cross-conjugation is a special type of conjugation in a molecule, when in a set of three Pi bonds only two pi-bonds interact with each other by conjugation, the third one is excluded from interaction . In classical terms it means that the strict alternation of single and double bonds --CH=CH–CH=CH–CH-- (i.e., conjugated) is interrupted by two consecutive single bonds at each cross-conjugated point in the cross-conjugated pathway: --CH=CH–C(=CH)–CH=CH--. Examples of cross-conjugation can be found in molecules such as benzophenone, divinylether, dendralenes and fullerene. The type of conjugation has an impact on reactivity and molecular electronic transitions.

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