Premium
Density functional computations of proton affinity and gas‐phase basicity of proline
Author(s) -
Marino T.,
Russo N.,
Tocci E.,
Toscano M.
Publication year - 2001
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.134
Subject(s) - chemistry , proton affinity , protonation , intramolecular force , moiety , hydrogen bond , ring (chemistry) , proline , stereochemistry , density functional theory , proton , gas phase , crystallography , computational chemistry , molecule , amino acid , ion , organic chemistry , biochemistry , physics , quantum mechanics
An Erratum has been published for this article in Journal of Mass Spectrometry 37(2) 2002, 232. The proton affinity and gas‐phase basicity of proline were evaluated by using density functional theory coupling the B3‐LYP hybrid functional with the extended 6–311++G** basis set. Cis and trans conformations of the carboxyl moiety for both exo and endo ring structures were considered for the neutral proline. The results show that the most stable structure of proline has the endo ring conformation with the carboxyl group in the cis position. The structure at the global minimum is stabilized by an intramolecular hydrogen bond. The nitrogen of the ring in the exo form is the preferred protonation site. The calculated proton affinity (924.3 kJ mol −1 ) and gas‐phase basicity (894.4 kJ mol −1 ) are in very good agreement with the experimental counterparts. Copyright © 2001 John Wiley & Sons, Ltd.