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arXiv · 0910.0357

New method to estimate stability of chelate complexes

F. V. Grigoriev·A. Yu. Golovacheva·A. N. Romanov·O. A. Kondakova·V. B. Sulimov
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Abstract

A new method allowing calculation of the stability of chelate complexes with Mg2+ ion in water have been developed. The method is based on two-stage scheme for the complex formation. The first stage is the ligand transfer from an arbitrary point of the solution to the second solvation shell of the Mg2+ ion. At this stage the ligand is considered as a charged or neutral rigid body. The second stage takes into account disruption of coordinate bonds between Mg2+ and water molecules from the first solvation shell and formation of the bonds between the ligand and the Mg2+ ion. This effect is considered using the quantum chemical modeling. It has been revealed that the main contribution to the free energy of the complex formation is caused by the disruption/formation of the coordinate bonds between Mg2+, water molecules and the ligand. Another important contribution to the complex formation energy is change of electrostatic interactions in water solvent upon the ligand binding with Mg2+ ion. For all complexes under investigation the reasonable (in frame of 2 kcal/mol) agreement between calculated and experimental values are achieved.

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F. V. Grigoriev, A. Yu. Golovacheva, A. N. Romanov, O. A. Kondakova, V. B. Sulimov. 2009-10-02. New method to estimate stability of chelate complexes. https://arxiv.org/abs/0910.0357

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