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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.
The best-known example is benzene (C 6 H 6) with a conjugated system of six π electrons, which equals 4n + 2 for n = 1. The molecule undergoes substitution reactions which preserve the six π electron system rather than addition reactions which would destroy it. The stability of this π electron system is referred to as aromaticity. Still, in ...
In contrast to the rarity of Möbius aromatic ground state molecular systems, there are many examples of pericyclic transition states that exhibit Möbius aromaticity. The classification of a pericyclic transition state as either Möbius or Hückel topology determines whether 4N or 4N + 2 electrons are required to make the transition state aromatic or antiaromatic, and therefore, allowed or ...
In organic chemistry, Baird's rule estimates whether the lowest triplet state of planar, cyclic structures will have aromatic properties or not. The quantum mechanical basis for its formulation was first worked out by physical chemist N. Colin Baird at the University of Western Ontario in 1972.
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For Möbius systems there is an odd number of plus–minus sign inversions in the basis set in proceeding around the cycle. A circle mnemonic [3] was advanced which provides the MO energies of the system; this was the counterpart of the Frost–Musulin mnemonic [6] for ordinary Hückel systems.
Preheat oven to 425ºF with the rack set 5 to 6 inches from the top. Stir together butter and garlic in a bowl. Season with salt and pepper. Spread butter on cut side of bread, dividing evenly ...
WASHINGTON (Reuters) -The U.S. Supreme Court declined on Monday to decide whether federally mandated warnings on cigarette packs that graphically illustrate the health risks of smoking violate the ...