2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3
Deuterium substitution on two ortho-substituted-OCH2-fragments in Nitro-Benzo-9-Crown-3 induces low frequency shifts, positive mnDCj, in all 13C NMR resonances which is an indication of the increased shielding in this crown ether. The magnitude of these shifts vary from 15DC7=716 to 54DC3=15 ppb for...
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Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
2002-07-01
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| Series: | Iranian Journal of Chemistry & Chemical Engineering |
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| Online Access: | http://www.ijcce.ac.ir/article_9544_7e83964c971d4eb728e86c2fa121bd75.pdf |
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| author | Abolghasem Moghimi Majid Rastegar Mahdi Ghandi Hamid Reza Bijanzadeh |
| author_facet | Abolghasem Moghimi Majid Rastegar Mahdi Ghandi Hamid Reza Bijanzadeh |
| author_sort | Abolghasem Moghimi |
| collection | DOAJ |
| description | Deuterium substitution on two ortho-substituted-OCH2-fragments in Nitro-Benzo-9-Crown-3 induces low frequency shifts, positive mnDCj, in all 13C NMR resonances which is an indication of the increased shielding in this crown ether. The magnitude of these shifts vary from 15DC7=716 to 54DC3=15 ppb for C7 and C3 CD3COCD3, and C6D6 on mnDCj values were investigated. The mnDCj values depended more on the nature of the solvent than on the concentration. The order of induced isotope shifts is: 15D, 51D>24D, 42D>34D, 43D>56D, 65D>45D, 54D. The isotope shifts observed are suggested to be a sum of contributions from low frequency shift due to inductive-type and negative hyperconjugation perturbations. The C-D bond, as a poorer electron acceptor than a C-H bond induces less positive charge on directly attached oxygens O1 and O2. This in turn, causes shielding of C1 and C2 in C1O1CD2 and C2O2CD2 fragments. The difference in 34DC1 and 43DC2 values is attributed to the conformational dependence of the negative hyperconjugation. The C1 and C2, are in fact, not equally affected by the two CD2 groups by negative hyperconjoagation because of the existence of NO2 group attached to the benzene ring. |
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| format | Article |
| id | doaj.art-8d42b9bed18248a4abb8595261f5311c |
| institution | Directory Open Access Journal |
| issn | 1021-9986 1021-9986 |
| language | English |
| last_indexed | 2024-12-11T17:54:42Z |
| publishDate | 2002-07-01 |
| publisher | Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR |
| record_format | Article |
| series | Iranian Journal of Chemistry & Chemical Engineering |
| spelling | doaj.art-8d42b9bed18248a4abb8595261f5311c2022-12-22T00:56:06ZengIranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECRIranian Journal of Chemistry & Chemical Engineering1021-99861021-99862002-07-0121161295442H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3Abolghasem Moghimi0Majid Rastegar1Mahdi Ghandi2Hamid Reza Bijanzadeh3Chemistry Department, University of Imam Hossein, Tehran, P.O. Box 16575-347, I.R. IRANChemistry Department, University of Tehran, Tehran, I.R. IRANChemistry Department, University of Tehran, Tehran, I.R. IRANChemistry Department, University of Tarbiat Modares, Tehran, I.R. IRANDeuterium substitution on two ortho-substituted-OCH2-fragments in Nitro-Benzo-9-Crown-3 induces low frequency shifts, positive mnDCj, in all 13C NMR resonances which is an indication of the increased shielding in this crown ether. The magnitude of these shifts vary from 15DC7=716 to 54DC3=15 ppb for C7 and C3 CD3COCD3, and C6D6 on mnDCj values were investigated. The mnDCj values depended more on the nature of the solvent than on the concentration. The order of induced isotope shifts is: 15D, 51D>24D, 42D>34D, 43D>56D, 65D>45D, 54D. The isotope shifts observed are suggested to be a sum of contributions from low frequency shift due to inductive-type and negative hyperconjugation perturbations. The C-D bond, as a poorer electron acceptor than a C-H bond induces less positive charge on directly attached oxygens O1 and O2. This in turn, causes shielding of C1 and C2 in C1O1CD2 and C2O2CD2 fragments. The difference in 34DC1 and 43DC2 values is attributed to the conformational dependence of the negative hyperconjugation. The C1 and C2, are in fact, not equally affected by the two CD2 groups by negative hyperconjoagation because of the existence of NO2 group attached to the benzene ring.http://www.ijcce.ac.ir/article_9544_7e83964c971d4eb728e86c2fa121bd75.pdfnmr13c nmr2h isotope shift2h isotope labelingcrown ethersnitro-benzo-9-crown-3 |
| spellingShingle | Abolghasem Moghimi Majid Rastegar Mahdi Ghandi Hamid Reza Bijanzadeh 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3 Iranian Journal of Chemistry & Chemical Engineering nmr 13c nmr 2h isotope shift 2h isotope labeling crown ethers nitro-benzo-9-crown-3 |
| title | 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3 |
| title_full | 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3 |
| title_fullStr | 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3 |
| title_full_unstemmed | 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3 |
| title_short | 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3 |
| title_sort | 2h isotope effect on 13c chemical shifts of nitro benzo 9 crown 3 |
| topic | nmr 13c nmr 2h isotope shift 2h isotope labeling crown ethers nitro-benzo-9-crown-3 |
| url | http://www.ijcce.ac.ir/article_9544_7e83964c971d4eb728e86c2fa121bd75.pdf |
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