Difluorobenzenes revisited: an experimental and theoretical study of spin–spin coupling constants for 1,2‐, 1,3‐, and 1,4‐difluorobenzene |
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Authors: | Ibon Alkorta Fernando Blanco Janet E. Del Bene José Elguero Laura Hernández‐Folgado María‐Luisa Jimeno |
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Affiliation: | 1. Instituto de Química Médica (CSIC), Juan de la Cierva, 3, E‐28006 Madrid, Spain;2. Department of Chemistry, Youngstown State University, Youngstown, OH 44555, USA;3. Centro de Química Orgánica ‘Lora‐Tamayo’, Juan de la Cierva, 3, E‐28006 Madrid, Spain |
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Abstract: | The experimental spin–spin coupling constants (SSCCs) for 1,3‐ and 1,4‐difluorobenzene have been determined anew, and found to be consistent with previously determined values. SSCCs for 1,2‐, 1,3‐, and 1,4‐difluorobenzene have been analyzed by comparing them with the coupling constants computed using the second‐order polarization propagator approximation (SOPPA) and the equation‐of‐motion coupled cluster singles and doubles method (EOM‐CCSD). Eighty experimental values have been analyzed using SOPPA calculations, and a subset of 40 values using both SOPPA and EOM‐CCSD approaches. One‐bond coupling constants 1J(C? C) and 1J(C? F) are better described by EOM‐CCSD, whereas one‐bond 1J(C? H) values are better described by SOPPA. An empirical equation is presented which allows for the prediction of unknown coupling constants from computed SOPPA values. A similar approach may prove useful for predicting coupling constants in larger systems. Copyright © 2009 John Wiley & Sons, Ltd. |
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Keywords: | 1H 13C 19F SOPPA EOM‐CCSD SSCCs difluorobenzenes |
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