[52186-89-7] · C6K4N6Ni2 · Potassium Hexacyanodinickelate · (MW 429.90)
Physical Data: diamagnetic red solid.
Solubility: sol water; insol ethanol, liquid ammonia.
Form Supplied in: deep red solid.
Preparative Method: prepared from the reduction of potassium tetracyanonickelate with Potassium in ammonia. The product precipitates from solution as a deep red solid.1
Handling, Storage, and Precautions: blood red aqueous solutions of the reagent are decolorized by oxygen. The reagent must be handled under an inert atmosphere.
The title reagent has been little used in organic synthesis, but several reports indicated that it has some potential. For example, potassium hexacyanodinickelate reacts with alkynes in the presence of Sodium Borohydride to afford nitriles (eq 1).2 Conversion of cinnamyl bromide to the corresponding nitrile can be accomplished in aqueous acetone at rt in 83% yield.3
Treatment of benzylic halides with potassium hexacyanodinickelate in water affords bibenzyls in good yields (eq 2).4 The coupling of a-bromo ketones to 1,4-dicarbonyl compounds has also been reported although the yields are modest.3 When the reactions are performed in the presence of Carbon Monoxide, ketones are obtained (eq 2).3 Similar reactions have been reported with vinylic and allylic halides with varying results.3
Allan R. Pinhas
University of Cincinnati, OH, USA