CYCLOPENTADIENYLNICKEL COMPLEXES

Article abstract of DOI:10.1016/0022-328X(85)80190-X

The neutral complexes (η⁵-C5H5)NiXL (X = Cl, L = PPh3 (I); L = PCy3 (II); X = Br, L = PPh3 (III); L = PCy3 (IV); X = I, L = PPh3 (V); L = PCy3 (VI)) have been obtained by treatting NiX2L2 with thallium cyclopentadienide.The same reaction in the presence of TlBF4 gives cationic derivatives <η⁵-C5H5)NiL2>BF4 (L = 2PPh2Me (VII); L = dppe (VIII)), whereas mononuclear complexes containing two different ligands (L2 = PPh3 + PCy3 (IX)) or dinuclear <<(η⁵-C5H5)Ni(PPh3)>2dppe>(BF4)2 (X) are obtained from the reaction of III with TlBF4 in the presence of a different ligand.Reduction of cationic complexes with Na/Hg gives very unstable nickel(I) derivatives (η⁵-C5H5)NiL2, which could not be isolated purely.Similar reduction of neutral complexes under CO gives a mixture of decomposition products containing <(η⁵-C5H5)Ni(CO)>2 and nickel(0) carbonyls, whereas in the presence of acetylenes, dinuclear <(η⁵-C5H5)Ni>2(RCCR') (R = R'= Ph; R = Ph, R' = H) are obtained.