Extending the Row of Lanthanide Tetrafluorides: A Combined Matrix-Isolation and Quantum-Chemical Study
Thomas Vent-Schmidt, Zongtang Fang, Zachary Lee, David Dixon, Sebastian Riedel – 2016
Only the neutral tetrafluorides of Ce, Pr, and Tb as well as the [LnF₇]³⁻ anions of Dy and Nd, with the metal in the +IV oxidation state, have been previously reported. We report our attempts to extend the row of neutral lanthanide tetrafluorides through the reaction of laser‐ablated metal atoms with fluorine and their stabilization and characterization by matrix‐isolation IR spectroscopy. In addition to the above three tetrafluorides, we found two new tetrafluorides, ³NdF₄ and ⁷DyF₄, both of which are in the +IV oxidation state, which extends this lanthanide oxidation state to two new metals. Our experimental results are supported by quantum‐chemical calculations and the role of the lanthanide oxidation state is discussed for both the LnF₄ and [LnF₄]⁻ species. Most of the LnF₄ species are predicted to be in the +IV oxidation state and all of the [LnF₄]⁻ anions are predicted to be in the +III oxidation state. The LnF₄ species are predicted to be strong oxidizing agents and the LnF₃ species are predicted to be moderate to strong Lewis acids.