Antiaromaticity - Wikipedia
Antiaromaticity is a chemical property of a cyclic molecule with a π electron system that has higher energy, i.e., it is less stable due to the presence of 4n delocalised (π or lone pair) electrons in it, as opposed to aromaticity.
Antiaromaticity and Antiaromatic Compounds - Master Organic Chemistry
2017年3月27日 · Antiaromatic Compounds Are Unusually Unstable. What are the key factors that determine whether a molecule is antiaromatic? It is similar to the requirements for aromaticity, except for one key factor (in red). The molecule must have (4, 8, 12, 16…) pi electrons (summarized algebraically as “4n where n is a natural number”).
Antiaromaticity - an overview | ScienceDirect Topics
Antiaromaticity is the property of a closed-shell cyclic planar conjugated π-electron system having 4n instead of (4n+2)π electrons. From: Coordination Chemistry Reviews, 2005
Aromaticity and Antiaromaticity | Wiley Online Books
2022年10月14日 · In Aromaticity and Antiaromaticity: Concepts and Applications, a team of accomplished chemists delivers a comprehensive exploration of the evolution and critical aspects of aromaticity. The book examines the new global criteria used to evaluate aromaticity, including the Nucleus Independent Chemical Shift (NICS) index and the electronic indices ...
The application of aromaticity and antiaromaticity to reaction ...
2023年11月1日 · In this review, we will analyze the relationship between aromaticity and reaction mechanism to highlight the importance of density functional theory calculations and present it according to an approach via either aromatizing a transition state/product or destabilizing a reactant by antiaromaticity.
Aromatic, Antiaromatic, or Non-Aromatic? 13 Worked Examples
2017年3月3日 · Today, we’re going to look at the following 13 molecules and try to determine if they are aromatic or not: Let’s get started! 2. Benzene. The easiest example to start with is benzene, and it demonstrates how to use the table. It’s cyclic, conjugated, has 3 pi bonds and those pi bonds are all in the pi system.
2010年11月30日 · Defining Antiaromaticity • Introduced by Breslow in 1965 • Most criteria are the opposite of aromaticity • Hückel Rule: Planar 2n system • Chemical criteria – High kinetic reactivity • Energetic criteria – Low thermodynamic stability • Aromatic stabilization energy – Resonance energy • Hückel • Dewar • Structural criteria:
Aromatic Ions and Antiaromaticity - Chemistry LibreTexts
2023年1月23日 · Azulene is a stable blue crystalline solid that undergoes a number of typical aromatic substitution reactions. The unexpected instability of 4n π-electron annulenes has been termed " antiaromaticity ". Other examples may be cited.
Antiaromatic compounds: a brief history, applications, and the …
2021年1月1日 · Beginning from a historical viewpoint, this chapter discusses the evolution of the antiaromaticity concept—covering the early synthetic challenges of preparing cyclobutadiene, orbital symmetry considerations of antiaromaticity, and transformations that convert [4n] π-antiaromatic rings into “aromatic” systems, ending with a brief survey ...
The phenomenon of antiaromaticity in organic chemistry may simply be defined as a property of planar conjugated cyclic structures by which it becomes less stable than its acyclic conjugate. In order to find whether the compound is antiaromatic or not, it is a necessary pre-condition to