The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Nuclear magnetic resonance study of some paramagnetic hydrated fluorides》. Authors are Easwaran, K. R. K.; Srinivasan, R..The article about the compound:Nickel(ii)fluoridetetrahydratecas:13940-83-5,SMILESS:[H]O[H].[H]O[H].[H]O[H].[H]O[H].[Ni+2].[F-].[F-]).Quality Control of Nickel(ii)fluoridetetrahydrate. Through the article, more information about this compound (cas:13940-83-5) is conveyed.
A preliminary study of 1H and 19F in compounds of the type MF2.4H2O (M = Mn, Fe, Co, Ni, Zn) was carried out (at room temperature and 90°K.), to investigate the nature of the hyperfine interaction. The samples were prepared by dissolving the carbonates (except in the case of Fe, where pure Fe powder was used) in 40% HF and precipitating with EtOH. The Fe compound was not very stable, and was kept in vacuo. X-ray powder photographs revealed the Fe, Co, Ni, and Zn salts to be isomorphous. For the 1H resonance, an increase in line width at low temperatures is attributed to the increase in the electronic polarization. The 19F fractional shift, α, increased through the Ni++, Co++, Fe++ series (increasing number of unpaired spins) at room temperature This order was not preserved at lower temperatures Paramagnetic susceptibilities were also measured at room temperature by the Gouy method.
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Reference:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider