On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions.
Current-density maps, calculated at the ab initio RHF//6-31G**/CTOCD-DZ level, show no significant pi ring current in planar equilateral geometries of neutral and dianionic [N]radialenes, oxocarbons and thiocarbons C(N)Y(N) (q-) (Y=CH(2), O, S; N=4, 5, 6; q=0 (1 a-12 a), 2 (1 b-12 b)). Only the N=3...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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2007
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| _version_ | 1797082843681128448 |
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| author | Domene, C Fowler, P Jenneskens, L Steiner, E |
| author_facet | Domene, C Fowler, P Jenneskens, L Steiner, E |
| author_sort | Domene, C |
| collection | OXFORD |
| description | Current-density maps, calculated at the ab initio RHF//6-31G**/CTOCD-DZ level, show no significant pi ring current in planar equilateral geometries of neutral and dianionic [N]radialenes, oxocarbons and thiocarbons C(N)Y(N) (q-) (Y=CH(2), O, S; N=4, 5, 6; q=0 (1 a-12 a), 2 (1 b-12 b)). Only the N=3 deltate dianions C(3)Y(3) (2-) (Y=CH(2), O, S (1 b, 5 b and 9 b)) have discernible pi ring current, and then with at most 20-25 % of the strength of the standard benzene current. On the magnetic criterion, lack of current is definitive evidence against aromaticity. Pictorial molecular-orbital analysis within the ipsocentric approach shows this to be an inevitable consequence of the nodal structure of the pi and pi* orbitals of [N]radialene-like systems. On grounds of angular-momentum symmetry, spatial distribution, or both, the HOMO-LUMO excitation does not contribute a significant central diamagnetic ring current. |
| first_indexed | 2024-03-07T01:33:37Z |
| format | Journal article |
| id | oxford-uuid:9464ef66-819c-49a2-b46c-d956ebce1894 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T01:33:37Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:9464ef66-819c-49a2-b46c-d956ebce18942022-03-26T23:39:13ZOn the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:9464ef66-819c-49a2-b46c-d956ebce1894EnglishSymplectic Elements at Oxford2007Domene, CFowler, PJenneskens, LSteiner, ECurrent-density maps, calculated at the ab initio RHF//6-31G**/CTOCD-DZ level, show no significant pi ring current in planar equilateral geometries of neutral and dianionic [N]radialenes, oxocarbons and thiocarbons C(N)Y(N) (q-) (Y=CH(2), O, S; N=4, 5, 6; q=0 (1 a-12 a), 2 (1 b-12 b)). Only the N=3 deltate dianions C(3)Y(3) (2-) (Y=CH(2), O, S (1 b, 5 b and 9 b)) have discernible pi ring current, and then with at most 20-25 % of the strength of the standard benzene current. On the magnetic criterion, lack of current is definitive evidence against aromaticity. Pictorial molecular-orbital analysis within the ipsocentric approach shows this to be an inevitable consequence of the nodal structure of the pi and pi* orbitals of [N]radialene-like systems. On grounds of angular-momentum symmetry, spatial distribution, or both, the HOMO-LUMO excitation does not contribute a significant central diamagnetic ring current. |
| spellingShingle | Domene, C Fowler, P Jenneskens, L Steiner, E On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions. |
| title | On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions. |
| title_full | On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions. |
| title_fullStr | On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions. |
| title_full_unstemmed | On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions. |
| title_short | On the lack of ring-current aromaticity of (heteroatom) [N]radialenes and their dianions. |
| title_sort | on the lack of ring current aromaticity of heteroatom n radialenes and their dianions |
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