Mechanochemical Synthesis, Characterization and Reactivity of a Room Temperature Stable Calcium Electride Article Swipe
YOU?
·
· 2024
· Open Access
·
· DOI: https://doi.org/10.1021/jacs.4c09408
· OA: W4403213943
A new calcium-based Room temperature Stable Electride (RoSE), K[{Ca[N(Mes)(SiMe<sub>3</sub>)]<sub>3</sub>(<i>e</i><sup><i>-</i></sup>)}<sub>2</sub>K<sub>3</sub>] (<b>2</b>), is successfully synthesized from the reaction of a calcium tris-amide, [Ca{N(Mes)(SiMe<sub>3</sub>)}<sub>3</sub>K] (<b>1</b>) (Mes = 2,4,6-trimethylphenyl), with potassium under mechanochemical treatment. The dimeric structure of K[{Ca[N(Mes)(SiMe<sub>3</sub>)]<sub>3</sub>(<i>e</i><sup><i>-</i></sup>)}<sub>2</sub>K<sub>3</sub>] is calculated using <i>ab initio</i> random structure searching (AIRSS) methods. This shows the existence of highly localized anionic electrons (<i>e</i><sup><i>-</i></sup>) and suggests poor electrical conductance, as confirmed via electroconductivity measurements. The two anionic electrons in <b>2</b> are strongly antiferromagnetically coupled, thus in agreement with the largely diamagnetic response from magnetometry. Reaction of <b>2</b> with pyridine affords 4,4'-bipyridine, while reaction with benzene gives C-H activation and formation of a calcium hydride complex, [K(η<sup>6</sup>-C<sub>6</sub>H<sub>6</sub>)<sub>4</sub>][{Ca[N(Mes)(SiMe<sub>3</sub>)](H)}<sub>2</sub>K<sub>3</sub>] (<b>3</b>). Computational DFT analysis reveals the crucial role played by the ligand framework in the stabilization of this new Ca-hydride complex.
