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Electrostatic bonding models: A test on group 1 and 2 metal complexes with H 2 O, NH 3 , H 2 S, PH 3 , and related ligands
Author(s) -
Magnusson Eric
Publication year - 1995
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540160809
Subject(s) - chemistry , ligand (biochemistry) , formal charge , divalent , ion , dipole , metal , adduct , binding energy , computational chemistry , point particle , relaxation (psychology) , molecule , crystallography , atomic physics , organic chemistry , physics , biochemistry , receptor , psychology , social psychology , quantum mechanics
Electrostatic models frequently proposed to describe ion–molecule interactions have been tested on the adducts formed by Group 1 and 2 cations with H 2 O, NH 3 , H 2 S, PH 3 , their methyl analogs, and their anions. The results from the model calculations were compared with all‐electron calculations (geometry optimized, MP2, TZP basis sets) carried out on adducts formed with Li + , Na + , K + , Ca 2+ , and Mg 2+ . The electrostatic potential model was utilized in two ways: The attraction of the point charge was calculated with and without relaxation of the ligand. A third model allowed relaxation of the ligand but treated the cation as a frozen core. The final model was the crude point charge/point dipole approximation. At long range, the models satisfactorily track the effects on energy of gross changes in the ion–ligand interaction (monovalent versus divalent ions, neutral ligands versus anions, parent ligands versus methyl derivatives), but correlation at close range is poor, especially for binding by divalent cations. The hypothesis that the calculated strength of cation–dipole binding is dependent on calculated dipole moment could not be verified. © 1995 by John Wiley & Sons, Inc.