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π‐Conjugation
Author(s) -
MiliánMedina Begoña,
Gierschner Johannes
Publication year - 2011
Publication title -
wiley interdisciplinary reviews: computational molecular science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.126
H-Index - 81
eISSN - 1759-0884
pISSN - 1759-0876
DOI - 10.1002/wcms.95
Subject(s) - conjugated system , excited state , valence bond theory , molecule , chemistry , simple (philosophy) , valence (chemistry) , computational chemistry , chemical physics , molecular orbital , theoretical physics , physics , atomic physics , organic chemistry , polymer , philosophy , epistemology
In the current overview, the concept of π‐conjugation in organic compounds is reexamined. Starting from valence bond and molecular orbital (MO) theory, the principal elements of conjugation are worked out starting from a simple Hückel picture; this includes the definition of the conjugated path, bond length alternation, as well as MO localization effects, and requires the distinction between formal and effective conjugation. The latter will be needed to understand the electronic and optical properties of polyconjugated molecules, highlighting the importance of a correct quantum chemical description of ground and excited state properties. Finally, implications of conjugation on interacting systems are shortly discussed. © 2011 John Wiley & Sons, Ltd. This article is categorized under: Structure and Mechanism > Molecular Structures