A series of N-aryl-3,4-(9′,10′-dihydroanthracene-9′, 10′-diyl)succinimides have been synthesized as model compounds to study the interaction of an aromatic π system with aliphatic H atoms and heteroatoms such as oxygen, sulfur, and fluorine. The steric requirements of the rigid scaffold forces the N-aryl residue and a benzene ring of the dihydroanthracenyl moiety to adopt an edge-to-face conformation in which one of the ortho-substituents of the N-aryl group interacts with the π system. The succinimides were generally obtained as mixtures of isomers and their ratios were considered as a function of the substitution pattern at the ortho positions of the N-aryl residue. The experimentally observed ratios were in good agreement with those predicted computationally by DFT calculations at the BMK/cc-pVDZ level of theory. From this study it was concluded that in these systems the aliphatic C-H/π interaction is mildly stabilizing and, to a certain extent, capable of overcoming unfavorable steric effects. On the other hand, the interaction of a π system with oxygen, sulfur, or fluorine atoms was destabilizing. When methyl or ethyl groups were allowed to compete with oxygen and fluorine for interaction with the benzene ring, C-H/π interactions were consistently observed to preferentially occur despite unfavorable steric effects.
Aliphatic C–H/π and Heteroatom/π Interactions in N-Aryl-3,4-(9′,10′-dihydroanthracene-9′,10′-diyl)succinimides / L. Raimondi, M. Benaglia, F. Cozzi. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - 2014:23(2014), pp. 4993-4998. [10.1002/ejoc.201402288]
Aliphatic C–H/π and Heteroatom/π Interactions in N-Aryl-3,4-(9′,10′-dihydroanthracene-9′,10′-diyl)succinimides
L. RaimondiPrimo
;M. BenagliaSecondo
;F. Cozzi
2014
Abstract
A series of N-aryl-3,4-(9′,10′-dihydroanthracene-9′, 10′-diyl)succinimides have been synthesized as model compounds to study the interaction of an aromatic π system with aliphatic H atoms and heteroatoms such as oxygen, sulfur, and fluorine. The steric requirements of the rigid scaffold forces the N-aryl residue and a benzene ring of the dihydroanthracenyl moiety to adopt an edge-to-face conformation in which one of the ortho-substituents of the N-aryl group interacts with the π system. The succinimides were generally obtained as mixtures of isomers and their ratios were considered as a function of the substitution pattern at the ortho positions of the N-aryl residue. The experimentally observed ratios were in good agreement with those predicted computationally by DFT calculations at the BMK/cc-pVDZ level of theory. From this study it was concluded that in these systems the aliphatic C-H/π interaction is mildly stabilizing and, to a certain extent, capable of overcoming unfavorable steric effects. On the other hand, the interaction of a π system with oxygen, sulfur, or fluorine atoms was destabilizing. When methyl or ethyl groups were allowed to compete with oxygen and fluorine for interaction with the benzene ring, C-H/π interactions were consistently observed to preferentially occur despite unfavorable steric effects.Pubblicazioni consigliate
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