Electron exchange reactions between tungsten hexachloride and nitrogen donors

The 1:1 molar reactions of WCl6 with a selection of aliphatic amines, in CH2Cl2 at room temperature, led to the isolation of the W(V) salts [amineH][WCl6] (amine = NEt3, 1; NHEt2, 2; pyrrolidine, 3; NH2CH2Ph, 4), in 47–57% yields. Analogously, [dmpH][WCl6], 5, was obtained in 55% yield from WCl6/3,5-dimethylpyrazole (dmp). The 1:2 molar reactions of WCl6 with NEt3 and NH2CH2Ph afforded the W(IV) salts [NHEt3]2[WCl6], 6, and [NH3CH2Ph]2[WCl6], 7, in 50–52% yields, respectively. Compounds 1–7 were characterized by analytical and spectroscopic methods, in addition the molecular structures of 2, 5 and 6 were ascertained by single crystal X-ray diffraction studies. A possible pathway regarding the 1:1 molar reaction of WCl6 with triethylamine is proposed on the basis of DFT calculations. The iminium [PhCH = NH2]+ cation was identified as a co-product in the mixtures obtained from WCl6 and variable amounts of benzylamine.

Graphical abstractAmmonium salts containing either W(V) or W(IV) chloride anions have been isolated from the reactions of WCl6 with limited amounts of aliphatic amines, or 3,5-dimethylpyrazole.Figure optionsDownload full-size imageDownload as PowerPoint slide