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Ab Initio investigation of the structure of hydrogen halide‐amine complexes in the gas phase and in a polarizable medium
Author(s) -
Kurnig Ingrid J.,
Scheiner Steve
Publication year - 1987
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.560320809
Subject(s) - chemistry , amine gas treating , polarizability , halide , proton affinity , polarizable continuum model , ab initio , solvent , gas phase , ion , proton , hydrogen halide , hydrogen , computational chemistry , ab initio quantum chemistry methods , solvent effects , solvation , protonation , nitrogen , inorganic chemistry , halogen , molecule , organic chemistry , physics , alkyl , quantum mechanics
Abstract The geometries of all 12 complexes in which HF, HCl, or HBr is paired with NH 3 , NMeH 2 , NMe 2 H, or NMe 3 are optimized with the MINI‐1 basis set. As the basicity of the amine is increased via progressive methylation, or as the proton affinity of the halide is diminished, the proton equilibrium position shifts toward the nitrogen, but in no case is this shift far enough to classify the complex as an ion pair. When the effects of a polarizable medium are included via the SCRF formalism, the shift of the proton toward the nitrogen is enhanced by increases in the solute‐solvent interaction such that relatively modest coupling leads to complexes of ion‐pair type. In all cases, complexes containing HBr are the most sensitive to either the basicity of the amine or the influence of the medium whereas the HF analogs are affected very little.