A 13C nmr study of metal ion binding to pyridoxine

Abstract
13C nmr confirms that coordination of metal ions by pyridoxine is through the C-3 and C-4′ oxygens in aqueous solution. Nitrogen appears to become more effective as a donor site in water–dimethylsulfoxide mixtures, while with increasing proportions of DMSO some cations are coordinated by DMSO rather than by pyridoxine. Changes in 13C spin–lattice relaxation times on metal ion coordination are more informative about metal binding sites than changes in 13C chemical shift. Some analogous results are reported for pyridoxamine.
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