| How nitrogen modifies the nuclear magnetic shielding in tetraazanaphthalenes. | |
| | |
MedLine Citation:
|
PMID: 19458830 Owner: NLM Status: PubMed-not-MEDLINE |
Abstract/OtherAbstract:
|
Although for planar conjugated hydrocarbons the out-of-plane component of proton magnetic shielding is an unquestionable quantitative aromaticity indicator, the same is not true for tetraazanaphthalenes. As in these compounds the (core + sigma)-currents associated to the nitrogen nuclei diminish the perpendicular component of shielding, abnormal values of (1)H NMR sigma(zz) are obtained. Therefore, a consistent aromaticity measure must be based only on the pi-contribution to the out-of-plane component of proton magnetic shielding. Otherwise, the behavior of these compounds in presence of an external magnetic field parallels that of naphthalene, with the nitrogen nuclei contributing to the ring current in a comparable amount to carbon nuclei. The pi-current contribution to magnetic shielding represents 6-8% of the out-of-plane shielding for nitrogen and 9-12% for carbon. |
| | |
Authors:
|
Inmaculada García Cuesta; José Sánchez Marín; Alfredo M J Sánchez de Merás |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-03-26 |
Journal Detail:
|
Title: Physical chemistry chemical physics : PCCP Volume: 11 ISSN: 1463-9076 ISO Abbreviation: Phys Chem Chem Phys Publication Date: 2009 Jun |
Date Detail:
|
Created Date: 2009-05-21 Completed Date: 2009-07-29 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 100888160 Medline TA: Phys Chem Chem Phys Country: England |
Other Details:
|
Languages: eng Pagination: 4278-85 Citation Subset: - |
Affiliation:
|
Instituto de Ciencia Molecular, Universidad de Valencia, P.O. Box 22085, E-46071, Valencia, Spain. garciain@uv.es |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Electrodeposition of copper composites from deep eutectic solvents based on choline chloride.
Next Document: Spontaneous charge separation induced by phenothiazine sorption within acidic H(n)ZSM-5.