Dipotassium Hexafluoronickelate(2-)

• CAS: 17218-47-2
• Catalog Number: ACM17218472
• Category: Main Products
• Molecular Weight: 250.88
• Molecular Formula: F6K2Ni+
• Synonyms: Potassiumhexafluoronickelate
• Appearance: Pink-purple powder

Case Study

Dipotassium Hexafluoronickelate for Nickel Incorporation in Polytyramine-Modified Graphite Electrodes

de Castro, Cláudio M., et al. Journal of Materials Science, 2008, 43, 475-482.

This study reported the modification of graphite electrode surfaces by electrochemical polymerization of tyramine, and further electrochemical reduction of metals using potassium hexafluoronickelate solution to incorporate nickel into electrode films. It was found that the introduction efficiency of nickel was higher in acidic media, and the greater the mass of nickel in the modified electrode prepared in acidic media, the greater the hydrogen current density generated.
Production of Ptyr films and Nickel incorporation on modified electrodes
· Before electropolymerization, the monomer solutions were deoxygenated using nitrogen gas. Polytyramine (Ptyr) films were synthesized on graphite electrodes through potentiodynamic electropolymerization using a tyramine solution at a concentration of 15 mmol L-1. A 0.5 mol L-1 HClO4 solution was used for all experiments, with pH adjustments made using NaOH solution.
· Once the modified electrode was created, it was immersed in a potassium hexafluoronickelate solution (2 × 10^-2 mol L-1) for 20 minutes. The resulting electrode, which now contained the nickel complex, was thoroughly washed and placed in a cell containing KCl solution (0.1 mol L-1), where a potential of -1.0 V was applied for 120 seconds. This incorporation process was repeated three times for all modified electrodes. The mass of nickel incorporated in the Ptyr produced at various pH levels was calculated using Faraday's law for the electrochemical reduction of the incorporated ions.

Dipotassium Hexafluoronickelate for the Study of Selective Fluorination of Pyridine and Its Derivatives

Gryaznova, T. V., et al. Russian Chemical Bulletin, 2016, 65, 1798-1804.

The oxidative fluorination of pyridine and 4-ethylpyridine was studied under chemical and electrochemical conditions in the presence of transition metal (nickel, cobalt and silver in high oxidation states) salts using potassium hexafluoronickelate (K2NiF6) as a fluorinating agent.
The electrochemical CV studies indicated that when pyridine is added to potassium hexafluoronickelate, the oxidation peak shifts toward the cathode area, likely due to the generation of nickel(II) fluorides that oxidize at earlier stages. Substituted cyclohexanes can be fully fluorinated using the fluorinating reagents produced from potassium hexafluoronickelate in the presence of BF3 or anhydrous HF (essentially RNiF3 and NiF4).
Selective chemical fluorination of pyridine with potassium hexafluoronickelate at 80 °C yields 2-fluoropyridine (1) as the sole product, which is characterized by a singlet signal at δ19F -65.88 in its 19F NMR spectrum. The reaction, conducted with an excess of pyridine serving as both substrate and solvent, results in the initial crimson color of the potassium hexafluoronickelate solution fading after several hours, during which bright blue crystals and a beige crystalline powder form.
When potassium hexafluoronickelate was used as the catalyst at a reagent ratio of Py: K2NiF6: CsF = 1: 0.1: 2, electrolysis was carried out at 2.07 V (vs. Ag/AgNO3). Unlike the chemical reaction, the NMR spectrum of this reaction mixture showed a singlet at δ19F -128.8, indicating that the primary fluorination product in this scenario is 3-fluoropyridine (3).