Paramagnetic19F NMR and Electrospray Ionization Mass Spectrometric Studies of Substituted Pyridine Complexes of Chromium(III): Models for Potential Use of19F NMR to Probe Cr(III)-Nucleotide Interaction.
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 whether19F NMR would be a potentially useful probe of the binding of Cr3+to DNA. The19F 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.
Department of Chemistry and Coalition for Biomolecular Products, The University of Alabama, Tuscaloosa, AL 35487-0336, USA.
Nicholas R
NR
Rhodes
Ken
K
Belmore
Carolyn J
CJ
Cassady
John B
JB
Vincent
Chromium(III); Fluoropyridine; Nucleotide; Paramagnetic NMR; Trifluoromethylpyridine