Ricerc@Sapienza

Understanding the structural and dynamic properties of the Mg(II) ion would represent an important step forward towards the mechanistic comprehension of relevant biological and technological processes. Mg(II) plays in fact vital roles in all forms of life, many of which are not understood as yet, activating enzymes and nucleic acids and promoting their conformational transitions. Further, rechargeable Mg-ion batteries, where common electrolytes such as acetonitrile are employed, are gaining considerable interest as promising candidates for future energy storage systems.
X-ray Absorption Spectroscopy (XAS) is by far the most accurate spectroscopic technique for the determination of the local structure of ions in liquid systems. However, to date, the use of XAS to probe the structural and electronic properties of the Mg(II) ion in aqueous and non-aqueous solutions has been severely hampered by the requirement of soft X-rays, that need tailored beamline experimental set-ups (such as vacuum conditions and windowless beamlines) and special systems of detection.
In this project, we will address the need of innovative methods that may uncover the solvation properties of the Mg(II) ion through the use of X-rays. Specifically, by combining operando near edge X-ray absorption fine structure at ambient pressure with multivariate curve resolution, Density Functional Theory and Molecular Dynamics analyses, we will monitor in real time the chemical changes that take place at the surface of a Mg-containing solid system upon exposure to a series of solvating media, such as water, methanol and acetonitrile, and retrieve quantitative structural and electronic information for the reversibly dissolved Mg(II) ions in each of the investigated solvents.
We believe our results will pave the way for the application of operando soft XAS to access the often elusive properties of low-Z number metal ions involved in processes of chemical and biological interest.