3 research outputs found
Octafluorodirhenate(III) Revisited: Solid-State Preparation, Characterization, and Multiconfigurational Quantum Chemical Calculations
No full textA simple method for the high-yield
preparation of (NH<sub>4</sub>)<sub>2</sub>[Re<sub>2</sub>F<sub>8</sub>]·2H<sub>2</sub>O has been developed that involves the reaction
of (<i>n</i>-Bu<sub>4</sub>N)<sub>2</sub>[Re<sub>2</sub>Cl<sub>8</sub>] with molten ammonium bifluoride (NH<sub>4</sub>HF<sub>2</sub>). Using this method, the new salt [NH<sub>4</sub>]<sub>2</sub>[Re<sub>2</sub>F<sub>8</sub>]·2H<sub>2</sub>O was prepared in
∼90% yield. The product was characterized in solution by ultraviolet–visible
light (UV-vis) and <sup>19</sup>F nuclear magnetic resonance (<sup>19</sup>F NMR) spectroscopies and in the solid-state by elemental
analysis, powder X-ray diffraction (XRD), and infrared (IR) spectroscopy.
Multiconfigurational CASSCF/CASPT2 quantum chemical calculations were
performed to investigate the molecular and electronic structure, as
well as the electronic absorption spectrum of the [Re<sub>2</sub>F<sub>8</sub>]<sup>2–</sup> anion. The metal–metal bonding
in the Re<sub>2</sub><sup>6+</sup> unit was quantified in terms of
effective bond order (EBO) and compared to that of its [Re<sub>2</sub>Cl<sub>8</sub>]<sup>2–</sup> and [Re<sub>2</sub>Br<sub>8</sub>]<sup>2–</sup> analogues
