1H and 17O NMR study of H-bond dynamics in picolinic acid N-oxide solutions in acetonitrile-h3 and acetonitrile‑d3: Novel aspects of old casus

•Non-trivial effect of isotopomers of acetonitrile, as reaction media, on H-bond dynamics was deduced.•Traces of water, even in the micro-amount, substantially modify the structuring of acetonitrile.•Isotopic substitution CH3 → CD3 influents the micro-structuring and local fluctuations in solvent.•Structuring can distort the experimental outcomes of kinetics that occur in micro- to nanoseconds scales.