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AB initio MO study of the halogen cation basicities of some organic bases
Author(s) -
Alcamí M.,
Mó O.,
Yáñtez M.,
Abboud JoséLuis M.
Publication year - 1991
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610040309
Subject(s) - chemistry , proton affinity , trimethylphosphine , halogen , phosphine , fluorine , computational chemistry , proton , ab initio , affinities , thioether , molecular orbital , inorganic chemistry , ion , molecule , stereochemistry , organic chemistry , protonation , alkyl , physics , quantum mechanics , catalysis
Hartree—Fock calculations were performed to investigate the structure and relative stabilities of complexes between halogen cations and first‐ and second‐row bases. It is shown by means of both a qualitative perturbation molecular orbital treatment and a topological analysis of the electronic charge density that second‐row bases present enhanced halogen cation basicities compared with first‐row bases. In this respect the results predict that although the fluorine cation basicity of water is smaller than its proton affinity, the fluorine cation basicities of SH 2 , thioether, phosphine and trimethylphosphine are considerably higher than their proton basicities. Similarly, phosphine and trimethylphosphine should have chlorine cation basicities greater than their proton affinities, in contrast with ammonia and trimethylamine. The results also show that fluorine and chlorine cation basicities are more sensitive to methyl substitution than proton affinities.