The through‐space transmission of 77Se — 77Se coupling constants
The IPPP‐INDO method is applied to study different interactions as well as transmission mechanisms of 77Se — 77Se coupling constants in cis‐ and trans‐1,2‐bis(methylseleno)ethene. Preferential conformations were determined using a modified version of the PCILO‐CNDO method. The preferential conformat...
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Autores principales: | , , |
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Publicado: |
1987
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Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01928651_v8_n3_p265_Contreras http://hdl.handle.net/20.500.12110/paper_01928651_v8_n3_p265_Contreras |
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Sumario: | The IPPP‐INDO method is applied to study different interactions as well as transmission mechanisms of 77Se — 77Se coupling constants in cis‐ and trans‐1,2‐bis(methylseleno)ethene. Preferential conformations were determined using a modified version of the PCILO‐CNDO method. The preferential conformation of the cis compound is such that nonbonding electron pairs of both Se atoms overlap to some extent. In this conformation a large and positive through‐space transmission of the Fermi contact term of the 77Se — 77Se coupling takes place, which strongly depends on the Se — Se distances. The similarity between this coupling and others involving different nuclei is discussed. The total calculated coupling is in fair agreement with experimental values for similar compounds. The 77Se — 77Se coupling in the trans‐compound is largely dominated by the orbital interaction, which is mainly transmitted through the vinyl π‐electron system. Copyright © 1987 John Wiley & Sons, Inc. |
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