Conjugated system
system of connected p orbitals with delocalized electrons increasing molecular stability / From Wikipedia, the free encyclopedia
In chemistry, a conjugated system is a system of continuous and parallel p-orbitals with delocalized electrons. Conjugated systems are created by several multiple bonds, each separated by single bonds. In general, conjugated systems may lower the overall energy of the molecule and increase how steady it is. They can contain lone pairs, radicals or carbonium ions. The compound may be cyclic, acyclic, linear or mixed. In most cases, the atoms in a molecule are held together by single bonds (where orbitals from adjacent atoms overlap). Molecules which have a conjugated system have unique properties different from normal compounds created by the sharing of the delocalized electrons among many atoms.
Conjugation is the overlap of one p-orbital with another across a sigma bond (or single bond) that is in between. (The d-orbitals of larger atoms can also contribute to a conjugated system).[1]
A conjugated system has a region of overlapping p-orbitals, bridging the single bonds that are between. They allow a delocalization of pi electrons across all the adjacent aligned p-orbitals.[2] The pi electrons do not belong to a single bond or atom, but rather to a group of atoms.
The largest conjugated systems (with the greatest number of shared electrons) are in graphite, conductive polymers, and carbon nanotubes.