Nickel, dicyclopentadienyl

Naphthylacetamide, 32, 94 a-Naphthylcyanamide, 31, 20 /3-Naphthyl ethyl ether, 32, 97 a-NAPHTHYL isothiocyanate, 36, 56 /3-Naphthyl isothiocyanate, 36, 57 -Naphthyl methyl ether, 32, 100 a-Naphthylphenylacetylene, 34, 43 a-Naphthylthiourea, 36, 56 Neophyl chloride, 32, 90 Nickel, dicyclopentadienyl-, 36, 35 Nicotinamide, 30, 3 33, 52 Nicotinic acid, 6-hydroxy-, 36, 44 Nocotinonitrile, 33, 52... 

Although not so generally applicable for the preparation of dicyclopentadienyl metal compounds as the sodium cyclopenta-dienide method, the amine procedure represents the simplest preparation of ferrocene. The amine procedure can also be employed for dicyclopentadienylnickel (about 80% yield), using nickel bromide obtained by the action of bromine on nickel metal powder and 1,2-dimethoxyethane as the solvent. The method of preparation given here is a modified version of that originally described. ... 

Proton-magnetic-resonance shifts have been reported on solid samples of dicyclopentadienyl nickel (97), vanadium (98), and chromium (98). For the nickel compound, a shift to higher fields was observed in contrast to shifts to lower fields for vanadium and chromium. It was suggested that charge-transfer effects give a positive spin density to the carbon atoms in the nickel compound and a negative spin density to the carbon atoms in other cases, but the reason for this difference is not clear from molecular-orbital theory. 

These were made on the uncharged dicyclopentadienyls of vanadium, chromium, iron, cobalt, nickel, ruthenium, manganese, and magnesium,... 

Metal cyclopentadienyls have already proved to be of considerable technical interest. According to investigations carried out mainly in the United States, ferrocene is able to bring about smokeless combustion of fuel oil when added in amounts of 0.05% (1). Its use as an oil additive for jet motors and as an antiknock has also been proposed. Liquid ferrocene is said to have advantages as a thermally stable heat-transfer medium. Dicyclopentadienyl nickel also has possible applications, and dicyclopentadienyl titanium-dichloride has been studied in association with aluminum alkyls for the polymerization of ethylene (15, 133, 134). Finally, the carbonyl CHsC5H4Mn(CO)3 has been considered as a fuel additive in conjunction with tetraethyl lead (0). Other information is given in the patent literature (40). 

Synthesis of ferrocene in high yield by this method has been reported by a number of investigators (18,34-36,38). Wilkinson et al. (36) have described the preparation of ferrocene, and dicyclopentadienyl compounds of cobalt and nickel in yields of 80-90% anhydrous diethylamine served both as solvent and acceptor for hydrogen halide. This procedure for preparing ferrocene has been published in detail in Organic Synthesis (18). 

Many 7i-cyclopentadienyl complexes may be prepared from the reaction of alkali metal cyclopentadienides with ammonia-soluble transition metal salts such as nitrates and thiocyanates in liquid ammonia (2-30). The amine complexes, [M(NH3) ] (C5H5)2, lose ammonia when heated in vacuo, and the uncharged dicyclopentadienyl complexes of iron, cobalt, nickel, chromium, and manganese are obtained. 

Also useful for dicyclopentadienyl complexes of nickel and iron. Arene type ... 

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