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Theoretical aspects of the enhancement of metal binding affinity by intramolecular hydrogen bonding and modulating p: K a values

Motahari, A ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1039/c7nj02693e
  3. Publisher: Royal Society of Chemistry , 2017
  4. Abstract:
  5. Polyols were used as model ligands for Mg2+, Ca2+, and Zn2+ complexes to study the role of the hydrogen bond network on the metal binding affinity and modulation of successive pKa values using density functional theory. The results confirm that the acidity of polyols dramatically increases upon metal complexation in the order Zn2+ > Mg2+ > Ca2+. For example, the three H-site positions in the hydroxyl groups of the heptaol, bound to Zn2+, are 11.2, 29.9, and 30.9 pKa units (in methanol) more acidic than those of pure heptaol. This acidity enhancement leads to making polyols as good ligands toward complexation. For instance, the formation constants of the heptaol in the presence of Zn2+, Mg2+, and Ca2+ in methanol were 5.67 × 1071, 6.46 × 1066, and 1.26 × 1053 times lower than those in its third deprotonation state, respectively. The natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), and reduced density gradient (RDG) analyses show that the intramolecular hydrogen bond network and increment of carbon chain length lead to the enhancement of metal binding affinity. These findings can be used for the manipulation of ligands and metal cations in designing metalloproteins. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2017
  6. Keywords:
  7. Calcium ion ; Hydrogen ; Hydroxyl group ; Ligand ; Magnesium ion ; Metal ion ; Metalloprotein ; Methanol ; Polyol ; Zinc ion ; Acidity ; Article ; Binding affinity ; Binding site ; Chemical bond ; Collisionally activated dissociation ; Complex formation ; Conjugate ; Controlled study ; Density functional theory ; Density gradient ; Electron ; Energy ; Hydrogen bond ; Ionization ; Metal binding ; Natural bond orbital ; Priority journal ; Proton transport ; Quantum theory ; Solvation ; Static electricity
  8. Source: New Journal of Chemistry ; Volume 41, Issue 24 , 2017 , Pages 15110-15119 ; 11440546 (ISSN)
  9. URL: https://pubs.rsc.org/en/content/articlelanding/2017/nj/c7nj02693e#!divAbstract