In recent years, Astrochemistry (the field of Astronomy that studies the chemistry of molecules in space) has revealed the presence of large molecular organic species, both O-bearing and N-bearing, in the medium between stars (the interstellar medium or ISM). Some of these species are of pre-biotic interest due to their possible link to the emergence of life on Earth. Several research groups in the world have ex- tensively studied O-bearing complex organics in the past. However, N-bearing organics, although essential for theories of the origin of life, have not received as much attention. Besides, it has been recently shown that molecular isotopic ratios of N-bearing species are invaluable tools for revealing the origin of primitive Solar System materials and their potential connection with interstellar chemistry.
The scope of this PhD thesis is to provide observational constraints and enhance our understanding of the chemistry of N-bearing molecular species in the ISM. To achieve this, the first part of my thesis is dedicated to search for N-bearing pre-biotic molecules in the ISM and to explore the level of molecular complexity achieved by their chemistry. The second part of the thesis focuses on the nitrogen isotopic fractionation in space and the determination of galactocentric behaviour of the primordial nitrogen isotopic ratio 14N/15N. These results have implications for theories of the origin of life (in particular for the primordial RNA-world scenario) and the origin of primitive Solar System materials.