# Tag Info

## Hot answers tagged aromaticity

13

A very basic way to do this would be to draw a diagram that shows the p-orbitals going above and below the plane. For Borole, the bonding orbitals would look like as shown below (taken from the wikipedia page on Borole): Natural Bonding Orbitals of Borole. Structure optimised using ORCA BP86-D3BJ and def2- TZVPP basis set. The calculated occupencies of the ...

9

Simply for the beginners in organic chemistry, this explanation of aromaticity is good enough: An aromatic (or aryl) compound contains a set of covalently bound atoms with specific characteristics: A delocalized conjugated $\pi$ system, most commonly an arrangement of alternating single and double bonds. Coplanar structure, with all the contributing atoms ...

8

Benzocyclobutadiene has an aromatic benzene ring as well as an anti-aromatic cyclobutadiene ring. This gives it the characteristics of both aromatic and anti-aromatic compounds. Now, according to Cyclobutadiene and its related compounds, [1,p 180]: Benzocyclobutadiene, the monobenzo derivative of cyclobutadiene, is intermediate in structure between the ...

5

Anti-aromaticity is often not taught very clearly. Let me start, then, by emphasising that this anti-aromatic diradical state should not be taken as a real thing. It is a purely hypothetical state that may arise if the molecule adopted the shape of a planar regular polygon (i.e. square for $\ce{C4H4}$, octagon for $\ce{C8H8}$). Because of various reasons, ...

4

According to Huckel's rule Four Criteria for Aromaticity The molecule needs to be (1) planar, (2) cyclic, (3) fully conjugated, and has (4) 4n+2 electrons. Your molecule does not seem to be planar (b/c of N and O atoms) but assuming that it has a nearly planar conformation it satisfies all other criteria. You only need to count one of Oxygen's lone pair and ...

4

Two factors come into play: (1) the inherent difference in resonance energy is not as great as you might think, and (2) the greater tendency for a dissociable proton to bind more tightly to an oxime function rather than a phenol function appears to counterbalance the reduced $\pi$-electron bonding difference. Less than meets the eye Suppose you were to use ...

3

The given dihydroborinine is indeed anti-aromatic if is it fully conjugated and planar, but counting pi electrons in a conjugated ring is not as simple as it seems when you have boron in the ring. If the boron is not joined to a ligand, as in (mono)boronine or unhydrogenated diborinine, it could pass its electron deficiency into the sigma bonding framework ...

2

Yup, they aren't. With the saturated carbon atom in the ring, you can't get a delocalized ring of pi electrons that you would need to apply Huckel's Rule. A more rigorous analysis in Ref. [1] give us a curious conflict between theoretical and experimental results for this molecule. The theoretical calculations suggest that delocalization of the pi bond ...

2

Simpler explanations, can by their nature be less accurate than a detailed description, but are helpful in beginning to understand things. Getting to the heart of your question: “How is the aromaticity in graphene different from the aromaticity in benzene? . . . but is it possible to find a simpler if less accurate way to explain the difference,” Perhaps a ...

2

G3 is generally a term used to describe a particular computational model used in calculating molecular bonding in quantum chemistry. The G refers to Gaussian and 3 is just a third iteration of including additionally complex terms to the molecular orbital calculations being used. There's a brief discussion on wikipedia, but you'll find more extensive ...

1

As Ivan Neretin pointed out in the comments, $\pi$ bonds will remain same whether or not in resonance. However, if you have trouble counting the double bond equvalent, you can directly use the formula for it given as $$\ce{DU=\dfrac{2C+2-H+N-X}{2}}$$ so here number of carbons are C=23, H=21, N=1 which also gives 14 as the answer.

1

Plants like fully decomposed (composted) organic materials just like humans prefer cooked food. The solution which you are preparing, is going to hurt the plants rather badly. For example, cow dung is a good organic fertilizer but fresh manure will burn the plants. Why don't you bury this fish waste in the ground or soil, mix it with old leaves and let it ...

1

Cleavage of the double bond will lead to both compounds having two rings that are aromatic, however the amount of resonance energy(hence stability) will not be the same. Both systems will have a Cyclopentadienyl anion, but one will have a Cyclopropenium cation while the other has a Tropylium cation . As the Tropylium cation has more resonance structures, it ...

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