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Proton affinity of five‐membered heterocyclic amines: Assessment of computational procedures
Author(s) -
Rao J. Srinivasa,
Sastry G. Narahari
Publication year - 2005
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.20862
Subject(s) - proton affinity , protonation , computational chemistry , basis set , chemistry , affinities , ab initio , density functional theory , proton , polarization (electrochemistry) , quantum chemistry , regioselectivity , molecule , stereochemistry , physics , quantum mechanics , organic chemistry , ion , supramolecular chemistry , catalysis
Ab initio quantum chemical calculations, G3B3, second‐order Møller–Plesset (MP2), and the hybrid density functional method B3LYP were employed to compute the proton affinities of 24 heterocyclic amines. A range of basis sets are employed, starting from double‐ζ polarization quality to triple‐ζ quality basis set with augmented diffuse and polarization function. Experimental values were used to calibrate the performance of various theoretical models. The regioselectivity for the protonation has been unambiguously established by performing B3LYP/6‐31G* calculations on the possible putative sites of attack. For the given series of compounds the performance of B3LYP/6‐31++G** and G3B3 levels of theory have been in excellent agreement with the experimental results with the deviations are of the order comparable with the experimental error. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006