The Perlin Effect in 2-halocyclohexanones and 2- halocyclohexanethiones

Publication date: Available online 19 February 2019Source: Computational and Theoretical ChemistryAuthor(s): Fátima M.P. de Rezende, Matheus P. Freitas, Teodorico C. RamalhoAbstractThe Perlin effect is an NMR phenomenon observed in six-membered rings and it is referred to as1JC−Hax<1JC−Heq. In the present work, the influence of halogens (F, Cl and Br) at position 2 in cyclohexanones and cyclohexanethiones is theoretically evaluated on the one-bond C2−H2 coupling constants, i.e. on the Perlin effect. An important hyperconjugative interaction (πC=Y→σ*C-H, Y = O and S) operating in the studied systems seems to play a significant role for the observed 1JC−Hax<1JC−Heq behavior. In addition, the Lewis contribution (JLewis) dominates the Fermi Contact term (JFC), which plays the major role for the overall one-bond C−H coupling constant. Compared to the gas phase, this behavior was found to be insensitive to implicit solvents (DMSO and water).Graphical abstract
Source: Computational and Theoretical Chemistry - Category: Chemistry Source Type: research
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