Anion receptor chemistry: does pi-anion interaction exist in the gas phase?

Proponente Caterina Fraschetti - Ricercatore
Sottosettore ERC del proponente del progetto
Componenti gruppo di ricerca

The present project aims to investigate the presence of a pi-hole interaction stabilizing a non-covalent system in the gas phase, through the study of its structure and conformational landscape by ESI-CID-MS and ESI-MS-IRMPD experiments. The anion receptor chemistry plays a role of increasing importance in the supramolecular chemistry field for the unquestionable importance to have a selective system, working for instance as pollutant sensor, transmembrane channel aimed to transport anions essential for life itself, and finally as an anion extractant, able to selectively transfer ions from water to organic solutions. In the context of a supramolecular architecture stabilization, between the noncovalent interactions involved in the anion sensing, we are focusing on the anion-pi interaction, that for long has not been accounted since it is counterintuitive. The contribution of anion-pi interaction involved in the formation of complexes between electron-deficient arenes and halide ions has been underlined in crystal lattices, but investigations in solution and even more in the gas-phase are definitely rare. Our experimental setup includes two mass spectrometers: a triple quadrupole provided with a linear ion trap and a Paul trap modified with a hole that allows a laser beam to enter and activate the trapped ion cloud. Both instruments are equipped with an electrospray ion source, that very often works as reaction chamber where species not stable in solution can be formed, kinetically trapped and then isolated in the gas-phase. The experimental results need the further support by the most suitable theoretical approach (DFT, QM or MD).

PE4_2, PE4_3, PE4_1

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