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A new cross-conjugated mesomeric betaine
Cross-conjugated mesomeric betaine (CCMB) has been defined as the dipolar species in which positive and negative charges are exclusively restricted to different parts of the molecule. In contrast to indolizine which undergoes [8+2] cycloaddition with dimethyl acetylenedicarboxylate (DMAD), its 1-aza...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9037020/ https://www.ncbi.nlm.nih.gov/pubmed/35478922 http://dx.doi.org/10.1039/d1ra03981d |
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author | Sharma, Nivedita Kour, Manjinder Gupta, Raakhi Bansal, Raj K. |
author_facet | Sharma, Nivedita Kour, Manjinder Gupta, Raakhi Bansal, Raj K. |
author_sort | Sharma, Nivedita |
collection | PubMed |
description | Cross-conjugated mesomeric betaine (CCMB) has been defined as the dipolar species in which positive and negative charges are exclusively restricted to different parts of the molecule. In contrast to indolizine which undergoes [8+2] cycloaddition with dimethyl acetylenedicarboxylate (DMAD), its 1-aza analogue, namely imidazo[1,2-a]pyridine reacts with the same reagent to afford the first representative of the CCMB isoconjugate with the odd non-alternant hydrocarbon anion. The structure of the product could be assigned on the basis of the NMR and HRMS results. Furthermore, the spectral studies indicated the presence of additional DMAD molecules in CCMB, possibly in the form of a charge-transfer (CT) complex. The whole sequence of reactions initiated by the attack of imidazo[1,2-a]pyridine on DMAD could be rationalized on the basis of the computational study of a model reaction sequence at the DFT (B3LYP/6-31+G(d)) level indicating the formation of a new CCMB derivative. The electronic excited states of the product were investigated by time-dependent density functional theory (TDDFT) calculations at the wB97XD/6-311++G(d,p) level, which indicate low-lying charge transfer that is characteristic of the CCMBs. |
format | Online Article Text |
id | pubmed-9037020 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-90370202022-04-26 A new cross-conjugated mesomeric betaine Sharma, Nivedita Kour, Manjinder Gupta, Raakhi Bansal, Raj K. RSC Adv Chemistry Cross-conjugated mesomeric betaine (CCMB) has been defined as the dipolar species in which positive and negative charges are exclusively restricted to different parts of the molecule. In contrast to indolizine which undergoes [8+2] cycloaddition with dimethyl acetylenedicarboxylate (DMAD), its 1-aza analogue, namely imidazo[1,2-a]pyridine reacts with the same reagent to afford the first representative of the CCMB isoconjugate with the odd non-alternant hydrocarbon anion. The structure of the product could be assigned on the basis of the NMR and HRMS results. Furthermore, the spectral studies indicated the presence of additional DMAD molecules in CCMB, possibly in the form of a charge-transfer (CT) complex. The whole sequence of reactions initiated by the attack of imidazo[1,2-a]pyridine on DMAD could be rationalized on the basis of the computational study of a model reaction sequence at the DFT (B3LYP/6-31+G(d)) level indicating the formation of a new CCMB derivative. The electronic excited states of the product were investigated by time-dependent density functional theory (TDDFT) calculations at the wB97XD/6-311++G(d,p) level, which indicate low-lying charge transfer that is characteristic of the CCMBs. The Royal Society of Chemistry 2021-07-21 /pmc/articles/PMC9037020/ /pubmed/35478922 http://dx.doi.org/10.1039/d1ra03981d Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/ |
spellingShingle | Chemistry Sharma, Nivedita Kour, Manjinder Gupta, Raakhi Bansal, Raj K. A new cross-conjugated mesomeric betaine |
title | A new cross-conjugated mesomeric betaine |
title_full | A new cross-conjugated mesomeric betaine |
title_fullStr | A new cross-conjugated mesomeric betaine |
title_full_unstemmed | A new cross-conjugated mesomeric betaine |
title_short | A new cross-conjugated mesomeric betaine |
title_sort | new cross-conjugated mesomeric betaine |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9037020/ https://www.ncbi.nlm.nih.gov/pubmed/35478922 http://dx.doi.org/10.1039/d1ra03981d |
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