Mixed-ligand complexes of boric acid with organic biomolecules

KÖSE D. A., Zumreoglu-Karan B.

CHEMICAL PAPERS, vol.66, no.1, pp.54-60, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 66 Issue: 1
  • Publication Date: 2012
  • Doi Number: 10.2478/s11696-011-0108-0
  • Journal Name: CHEMICAL PAPERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.54-60
  • Hacettepe University Affiliated: Yes

Abstract

Boric acid forms meta-stable complexes with biomolecules like amino and hydroxy acids and stable complexes with the diol group containing carbohydrates, vitamins, and nucleotides, yielding mono-chelate (1 : 1 complex) or bis-chelate (1 : 2 complex) structures with negatively charged tetrahedral borate anions. Here we report water-soluble, bio-available mixed-ligand boron adducts for potential nutritional and/or pharmaceutical applications. The complexes were prepared by complete esterification of boric acid with a number of acyclic-and cyclic hydroxy-functionalized biomolecules employing sodium as the counter ion. Structural and thermal properties of the complexes were investigated using chemical analysis, B-11 NMR, FTIR, and TGA-DTA techniques. Complexes containing salicylic acid as one of the ligands displayed higher thermal and hydrolytic stabilities. (C) 2011 Institute of Chemistry, Slovak Academy of Sciences