Volume 1, Number 3, July - December, 2015

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A detailed study of the proton affinities of a series of β-substituted acrylamides and their Oprotonated counterparts has been performed by B3LYP (DFT) method using 6-311G(d,p) basis sets with complete geometry optimization both before and after protonation. The gas phase O-protonation is observed to be exothermic and the local stereochemical disposition of the proton is found to be almost the same in each case. The presence of β-substituent is seen to cause very little change of the proton affinities, relative to the unsubstituted acrylamides. Computed proton affinities are sought to be correlated with a number of computed system parameters such as the Mulliken net charge on the carbonyl oxygen of the unprotonated bases, Mulliken net charge on the carbonyl oxygen and Mulliken net charge on the proton of the protonated bases. The overall basicity is explained by the distant atom contribution in addition to the contribution from the carbonyl group. The electron-releasing substituents are seen to increase the computed proton affinities (PAs) while the electronwithdrawing groups have an opposite effect as expected (Ref: Biswarup Mandal, Umasankar Senapati, Bhudeb Ranjan De. The proton affinities of a series of β-substituted Acrylamide in the ground state: A DFT based computational study. Discovery Chemistry, 2015, 1(3), 64-71).

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The proton affinities of a series of β-substituted Acrylamide in the ground state: A DFT based computational study


Biswarup Mandal, Umasankar Senapati, Bhudeb Ranjan De

A detailed study of the proton affinities of a series of β-substituted acrylamides and their O-protonated counterparts has been performed by B3LYP (DFT) method using 6-311G(d,p) basis sets with complete geometry optimization both before and after protonation. The gas phase O-protonation is observed to be exothermic and the local stereochemical disposition of the proton is found to be almost the same in each case. The presence of β- substituent is seen to cause very little change of the proton affinities, relative to the unsubstituted acrylamides. Computed proton affinities are sought to be correlated with a number of computed system parameters such as the Mulliken net charge on the carbonyl oxygen of the unprotonated bases, Mulliken net charge on the carbonyl oxygen and Mulliken net charge on the proton of the protonated bases. The overall basicity is explained by the distant atom contribution in addition to the contribution from the carbonyl group. The electron-releasing substituents are seen to increase the computed proton affinities (PAs) while the electron-withdrawing groups have an opposite effect as expected.

Discovery Chemistry, 2015, 1(3), 64-71

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