Abstract
Oxygen is a ubiquitous element present in many inorganic, organic and hybrid compounds. It has three naturally stable isotopes: 16O (99.76 % natural abundance), 17O (0.04 %) and 18O (0.20 %). Using analytical techniques that rely on the minor oxygen isotopes can bring additional information regarding the structure and reactivity of oxygen-containing compounds. Unfortunately, due to the very low natural abundance of 17O/18O, such analyses often require to work with compounds enriched 17O/18O.In this thesis, new labeling schemes for 17O/18O-enrichment of carboxylic acids based on mechanochemistry were developed using enriched water as a source of 17O/18O-isotopes. All mechanochemical reactions were performed at room temperature and atmospheric pressure providing 17O/18O-labeled products rapidly, in a user-friendly way and a cost-efficient manner. In particular, two different mechanochemical protocols were developed for 17O/18O-labeling of fatty acids: a CDI-activation/hydrolysis approach and a saponification approach. For the labeling of amino acids, the mechanochemical saponification was applied and the results were compared to the acid-catalysed oxygen exchange approach. All the enriched products were isolated pure in moderate to high yields, and characterized by various analyses, including 17O solid-state NMR spectroscopy.In addition, 17O-enriched oleic acid was used for the synthesis of two materials systems: zinc oleate and oleic acid-grafted ZnO nanoparticles. Oxygen-17 solid-state NMR was then used to explore their structure and to describe their reactivity under UV light irradiation. In parallel, the 17O/18O-enriched amino acids were Fmoc-protected and used for the synthesis of the 17O/18O-labeled peptides RGD and GRGDS, which were also characterized by solid-state 17O NMR.