Cyclopentadienyl Grignard Reagents compounds

Catenated Organic Compounds of the Group IV Elements, 4,1 Conjugate Addition of Grignard Reagents to Aromatic Systems, 1, 221 Cyclobutadiene Metal Complexes, 4, 95 Cyclopentadienyl Metal Compounds, 2, 365 Diene-Iron Carbonyl Complexes, 1, 1... 

The nickel complex, Ni ( 5115)2, has been made by the action of the Grignard reagent on nickel (II) acetylacetonate (217) or from potassium cyclopentadienyl and the ammine [Ni(NHs)el (S N)2 in liquid ammonia (58). It forms dark emerald-green crystals which sublime at 80-90° and which, when heated in nitrogen, melt, with decomposition and the formation of a nickel mirror, at 173-174°. It is only slowly oxidized in air, and cold water neither attacks nor dissolves it it is, however, readily soluble in organic liquids. Oxidation of the compound yields an orange-yellow solution containing the ion [Ni( 5H5)2]+, which is stable for a short period in weakly acidic media, and which may be precipitated as the reineckate or tetraphenylborate. 

---