Paramagnetic 19F NMR and Electrospray Ionization Mass Spectrometric Studies of Substituted Pyridine Complexes of Chromium(III): Models for Potential Use of 19F NMR to Probe Cr(III)-Nucleotide Interaction

Nicholas R Rhodes; Ken Belmore; Carolyn J Cassady; John B Vincent

doi:10.1016/j.poly.2013.03.002

Paramagnetic ¹⁹F NMR and Electrospray Ionization Mass Spectrometric Studies of Substituted Pyridine Complexes of Chromium(III): Models for Potential Use of ¹⁹F NMR to Probe Cr(III)-Nucleotide Interaction

Polyhedron. 2013 Nov 12:64:10.1016/j.poly.2013.03.002. doi: 10.1016/j.poly.2013.03.002.

Authors

Nicholas R Rhodes¹, Ken Belmore, Carolyn J Cassady, John B Vincent

Affiliation

¹ Department of Chemistry and Coalition for Biomolecular Products, The University of Alabama, Tuscaloosa, AL 35487-0336, USA.

Abstract

The synthesis and characterization of chromium basic carboxylate complexes, [Cr₃(O₂CR)₆L₃]⁺, containing trifluoroacetate, 3-fluoropyridine, 3-trifluoromethylpyridine, and 4-trifluoromethylpyridine are described. The substituted pyridine ligands are used as models of DNA bases to determine whether ¹⁹F NMR would be a potentially useful probe of the binding of Cr³⁺ to DNA. The ¹⁹F NMR resonances of the coordinated ligands, while broadened by delocalization of unpaired electron density from the S=3/2 chromic centers, are readily discernable, and the contact shifts are of sufficient magnitude that the signals from coordinated and free ligands can easily be differentiated. Thus, ¹⁹F NMR appears to be a potentially useful probe of the binding of Cr³⁺ to DNA containing F-labeled bases. Additionally, electrospray MS is shown to be a convenient method to establish the identity of chromium basic carboxylate assemblies.

Keywords: Chromium(III); Fluoropyridine; Nucleotide; Paramagnetic NMR; Trifluoromethylpyridine.

Grants and funding

R21 AT003485/AT/NCCIH NIH HHS/United States