The results also suggest that in compounds 1–3, the hydrogen elimination are controlled by LP(e) → σ* resonance energies. Azulene, which has a specific structure of ring-fused unsaturated seven- membered and five-membered rings, is a typical non-benzenoid aromatic. It is a system of two fused rings, one containing 7 and the other 5 carbons.
Based on the optimized ground state geometries using the MPW1PW91/6-31++G** method, the natural bond orbital analysis (NBO) of donor–acceptor (bonding-antibonding) interactions revealed that by the increase of electronegativity of atom $ $ resonance energies and also, the HOMO-LUMO energy-gaps in the ground state structures increase. What are non benzenoid compounds give an example The most basic example of non benzenoid aromatic compound is AZULENE. The nucleus independent chemical shift (NICS) values of all reactants, TSs and products indicate that all studied structures are aromatic and the studied reactions are controlled kinetically and thermodynamically by the change of the aromaticity.
Our results show that the MPW1PW91/6-31++G** method is in good agreement with the available experimental values. We already learn that aromatic compounds are mainly divided into two types: benzenoid and non benzenoid.īenzenoid compounds are aromatic compounds that have at least one benzene ring at its chemical can be characterised by the presence of one or more fused or isolated benzene ring in their structure.A theoretical study of the thermal decomposition kinetics of 2,5-dihydrofuran (1), 2,5-dihydrothiophene (2), and 3-pyrroline (3) has been carried out at the B3LYP/6-31++G**, B3PW91/6-31++G** and MPW1PW91/6-31++G** levels of theory. When we look at flow charts Aromatic compounds are mainly divided into benzenoid and non-benzenoid compounds.
If a compound follows the above rules then it is said to be an aromatic compound. General criteria must be met if a molecule is said to show aromaticity.Īn aromatic molecule must possess planar cyclic structureĪromatic rings must contain only $s$ is an integer.
0 kommentar(er)
