R. S. Kumar, R. Sabesan, S. Krishnan
2002
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0
Influential Citations
13
Citations
Journal
Journal of Molecular Liquids
Abstract
Abstract The experimental values of the dipolar increments of the complexes of 2,6 diphenyl piperidin-4-one and 3,5 dimenthyl 2,6 diphenyl piperidin-4-one with 2,3,5 trimethyl phenol, p-cresol, p-chlorophenol, 2,4 dichlorophenol and p-nitrophenol in dilute solutions of carbon tetrachloride were determined at 303K at 2MHz. The preferred orientation of the piperidones is a chair conformation with a slight flattening of the ring on methyl substitution and the nitrogen lone pair is equatorial to the heterocyclic ring. The dipolar increment is consistent with pKa values if θb is taken in the vicinity of 90° which implies that H-bond formation is between the OH group and the N-atom rather than the carbonyl oxygen. The through bond interaction in piperidones is found to be quenched by methyl substitution.