Phosphate binding by a novel Zn(II) complex featuring a trans-1,2-diaminocyclohexane ligand. Effective anion recognition in water

Org Biomol Chem. 2015 Feb 14;13(6):1860-8. doi: 10.1039/c4ob02321h.

Abstract

In this work we have investigated the binding properties of a new synthetic receptor for phosphate anions that combines metal ion coordination with electrostatic and H-bonding interactions. The described receptor is obtained by assembling an iminodiacetic (IDA) fragment, as a Zn(II) binding site, with a polyamine macrocyclic portion containing two trans-1,2-diaminocyclohexane (DAC) units and a pyrrole ring, as a cationic binding site, into an adaptive structure appropriately spanning the length of di- and tridentate phosphates. Potentiometric measurements together with (1)H and (31)P NMR investigation showed that, in a wide pH range including values of physiological interest, the Zn(II) complex of the receptor binds di- and triphosphates, such as ADP, ATP, pyrophosphate (PP) and triphosphate (TP), far better than monophosphate (MP), and that TP is poorly bound by methyliminodiacetate (MIDA) as a model for the Zn(II) binding site. Besides the excellent selectivity over other phosphates, the affinity for TP is the largest reported to date for Zn(II) complexes in water.

MeSH terms

  • Anions / chemistry
  • Binding Sites
  • Cyclohexylamines / chemistry*
  • Ligands
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry*
  • Phosphates / chemistry*
  • Water / chemistry*
  • Zinc / chemistry*

Substances

  • Anions
  • Cyclohexylamines
  • Ligands
  • Organometallic Compounds
  • Phosphates
  • Water
  • 1,2-cyclohexanediamine
  • Zinc