Hydrogen and copper ion-induced molecular reorganizations in scorpionand-like ligands. A potentiometric, mechanistic, and solid-state study

Inorg Chem. 2007 Jul 9;46(14):5707-19. doi: 10.1021/ic700643n. Epub 2007 Jun 8.

Abstract

Two aza scorpionand-like macrocycles (L2 and L3) have been prepared. L2 consists of a tren amine with two of its arms cyclizized with a 2,6-bis(bromomethyl)pyridine. In L3, the remaining pendant arm has been further functionalized with a fluorophoric naphthalene group. X-ray data on the compounds [H(L3)]ClO4.H2O (1) and [H3(L3)](H2PO4)3.H2O (2) as well as solution studies (pH-metry, UV-vis, and fluorescence data) show the movement of the pendant arm as a result of the protonation degree of the macrocycles and of the formation of intramolecular hydrogen bonds. X-ray data on the complexes [Cu(L2)](ClO4)2]2.H2O (3) and [Cu(L3)](ClO4)2 (4) and solution studies on Cu2+ coordination show the implication of the nitrogen of the arm in the binding to the metal ion. Kinetic studies on the decomposition and formation of the Cu2+ complexes provide additional information about the pH-dependent molecular reorganizations. Moreover, the obtained information suggests that the kinetics of the tail on/off process is essentially independent of the lability of the metal center.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Copper / chemistry*
  • Hydrogen / chemistry*
  • Hydrogen-Ion Concentration
  • Ions / chemistry*
  • Kinetics
  • Ligands
  • Models, Molecular
  • Molecular Structure
  • Phosphorus Acids / chemistry
  • Potentiometry
  • Water / chemistry
  • X-Ray Diffraction

Substances

  • Ions
  • Ligands
  • Phosphorus Acids
  • Water
  • Copper
  • Hydrogen