Developing deep eutectic solvents as sustainable media for homogeneous catalysis and energy storage

The chemical sciences are moving towards more sustainable (biodegradable, non-toxic, non-polluting, carbon-neutral, atmosphere-friendly, cheaper) processes. This thesis follows the green zeitgeist and describes the application of deep eutectic solvents (DESs) as potential green solvents in organometallic catalysis and the preparation of anthraquinones salts towards the development of redox-active DESs for energy storage applications. The first chapter reviews ionic liquids and DESs. Their differences and green attributes are discussed. The second chapter aims to detail the experimental and computational methodologies employed in this thesis. In the third chapter, two novel and affordable cross-coupling methodologies in DESs are described: a Suzuki reaction and a regioselective Negishi reaction. The Suzuki reaction was chemically robust and proceeded in DESs smoothly, whereas the Negishi reaction posed bigger challenges. Temperature was the most influential variable, and its careful control allowed to perform the Negishi reaction in DESs at open air, thus circumventing its need for protective atmosphere and dry solvents. With Pd3(OAc)6 pre-catalyst, the Negishi reaction exhibited good performance with iodoarenes functionalized at the ortho-position with metal-coordinating groups, whereas with [Pd(OAc)2(PPh3)2] pre-catalyst exhibited better performance with meta- or para-substituted iodoarenes. This feature was exploited in a regioselective Negishi reaction with methyl 2,3,5-triiodobenzoate that exhibited high selectivity for the ortho-monosubstituted product. The fourth chapter involves the preparation of anthraquinone salts as potential candidates for redox-active DESs.