Two Types of Intramolecular Lewis-Base Adducts with the [2-(Dimethylamino)ethyl]cyclopentadienyl Ligand: Synthesis and Crystal Structures of {η5:η1-C5H4[(CH2)2NMe2]}Ni−I and {η5-μ-C5H4[(CH2)2NMe2]}(Me3P)Ni−InI2,

The synthesis and reactivity of nickel complexes with the [2-(dimethylamino)ethyl]cyclopentadienyl ligand (Cp N ) are described. The reaction of NiBr 2 with Cp N Li leads to the new paramagnetic nickelocene derivative (Cp N ) 2 Ni ( 1 ), which has been characterized by 1 H and 13 C NMR, elemental analysis, and mass spectroscopy. Synproportionation of this complex with Ni(CO) 4 affords quantitatively the dimeric nickel complex [Cp N (CO)Ni] 2 ( 2 ). Reductive cleavage of 2 with KC 8 and trapping of the anionic intermediate with Me 3 SnCl gives the stannyl−nickel complex Cp N (CO)Ni−SnMe 3 ( 4 ). Reaction of 2 with Ga 2 Cl 4 yields the gallium−nickel complex (η 5 -μ-Cp N )(CO)Ni-GaCl 2 ( 7 ) with intramolecular coordination of the dimethylamino group to the gallium center. Oxidative cleavage of 2 with iodine and liberation of CO leads to the intramolecular chelate (η 5:η 1 -Cp N )Ni−I ( 3 ). The compounds (η 5 -μ-Cp N )(PR 3 )Ni−InI 2 with R = C 6 H 5 ( 5 ) and CH 3 ( 6 ) are obtained in good yields by insertion of low-valent indium halides InX (X = Br, I) into the Ni−I bond of 3 . X-ray diffraction determinations were carried out for 3 and 6, and for 6, a comparably short Ni−In distance of 241.80(7) pm was found.