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Theoretical study of the interaction of nonactin with Na + , K + , and NH 4 +
Author(s) -
Gresh Nohad,
Pullman Alberte
Publication year - 1982
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.560220405
Subject(s) - chemistry , intramolecular force , ionophore , intermolecular force , binding energy , interaction energy , intermolecular interaction , enthalpy , methanol , computational chemistry , inorganic chemistry , crystallography , stereochemistry , thermodynamics , molecule , organic chemistry , calcium , physics , nuclear physics
Abstract In an attempt to account for the preferential binding to nonactin of K + relative to Na + , theoretical computations are performed using the intermolecular interaction energies of the ionophore with the two cations. Both K + and Na + liganding conformations are considered, and an evaluation is made of the intramolecular energy expenditure caused by the reduction of the size of the cavity. The energy balance for the complexation of the two cations computed by taking into account the cation–ionophore interactions, the interactions between the liganding groups, as well as the desolvation enthalpies of the cations in methanol, favors K + over Na + by 4 to 5 kcal/mol, in fair agreement with the difference in the measured enthalpies of binding. The binding of NH 4 +to nonactin is also investigated.