Esther Matamoros Castellano

This paper explores and revisits in detail the formation and characterization of sugar-based aminonitriles, whose ultimate origin can be traced to the interaction of biomolecules with cyanide. Although the synthesis and spectroscopic data of 2-amino-aldononitriles were reported long ago, there are both contradictory and confusing results among the published data. We have now addressed this concern through an exhaustive structural elucidation of acylated 2-amino- and 2-alkyl(aryl)amino-2-deoxyaldonitriles using mass spectrometry and FT-IR, FT–Raman, and NMR spectroscopies. Several structures could be unambiguously determined through single-crystal X-ray diffraction, which allowed us to correct other misassignments. Moreover, this study unveils how steric and electronic effects influence the acylation outcome of the amino, (alkyl, aryl)amino, or acetamido group at C-2. The chirality at the latter, which was assigned tentatively through optical rotation correlation, and hence the preferential threo stereochemistry generated during the cyanohydrin synthesis of 2-amino-2-deoxy aldononitriles have now been established with confidence.

A family of acylhydrazones have been prepared and characterized with the aim of investigating their potential as information storage systems. Their well-established synthetic methodologies allowed for the preparation of seven chemically stable acylhydrazones in excellent yields that have been photophysically and photochemically characterized. In addition, DFT and TD-DFT calculations have been performed to gain more insights into the structural, energetic and photophysical properties of the E/Z isomers. Our results reveal that E/Z configurational isomerization upon irradiation is highly dependent on the stabilization of the E or Z isomers due to the formation of intramolecular H bonds and the electronic/steric effects intrinsically related to their structures. In addition, Raman spectroscopy is also used to confirm the molecular structural changes after the formation of hydrogen bonds in the isomers.