Long-range bonding interactions were evaluated using variable-temperature NMR spectroscopy and suitable 2'-CH2X-substituted phenylpyridines (X = Me, NMe2, OMe, F). It was found that the arylpyridyl rotational barriers were lower when electronegative atoms were bound to the α carbon of the 2' moiety. This effect was ascribed to a stabilizing interaction in the transition state due to the lone pair of the heterocyclic nitrogen with the α carbon. Computational support for this hypothesis came from CCSD(T)/6-31+G(d) calculations. Steric effects of the X moiety were ruled out by comparison of the rotational barriers of analogous biphenyls.
Long-range bonding/nonbonding interactions: A donor-acceptor resonance studied by dynamic NMR / Ruzziconi, R.; Lepri, S.; Buonerba, F.; Schlosser, M.; Mancinelli, M.; Ranieri, S.; Prati, L.; Mazzanti, A.. - In: ORGANIC LETTERS. - ISSN 1523-7060. - STAMPA. - 17:11(2015), pp. 5b01152.2740-5b01152.2743. [10.1021/acs.orglett.5b01152]
Long-range bonding/nonbonding interactions: A donor-acceptor resonance studied by dynamic NMR
MANCINELLI, MICHELE;RANIERI, SILVIA;PRATI, LUCA;MAZZANTI, ANDREA
2015
Abstract
Long-range bonding interactions were evaluated using variable-temperature NMR spectroscopy and suitable 2'-CH2X-substituted phenylpyridines (X = Me, NMe2, OMe, F). It was found that the arylpyridyl rotational barriers were lower when electronegative atoms were bound to the α carbon of the 2' moiety. This effect was ascribed to a stabilizing interaction in the transition state due to the lone pair of the heterocyclic nitrogen with the α carbon. Computational support for this hypothesis came from CCSD(T)/6-31+G(d) calculations. Steric effects of the X moiety were ruled out by comparison of the rotational barriers of analogous biphenyls.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
