NHC‐Stabilized Nickel Olefin, Dialkyl, and Dicyanido Complexes

The complexes trans‐ [Ni( i Pr 2 Im) 2 Br 2 ] 1 , trans ‐[Ni( i Pr 2 Im Me ) 2 Br 2 ] 2 , trans ‐[Ni(Me 2 Im) 2 I 2 ] 3 , and trans ‐[Ni(Me 2 Im Me ) 2 Br 2 ] 4 (R 2 Im = 1,3‐diorganyl‐imidazolin‐2‐ylidene, R 2 Im Me = 1,3‐diorganyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene) are useful precursor for the synthesis of NHC‐stabilized nickel olefin, alkyne, alkyl and cyanido complexes. [Ni(NHC) 2 (η 2 ‐olefin)] and [Ni(NHC) 2 (η 2 ‐alkyne)] can be prepared via metallic reduction in the presence of the olefin or alkyne, as exemplified by the synthesis of [Ni(Me 2 Im) 2 (η 2 ‐C 2 H 4 )] 5 , [Ni(Me 2 Im) 2 (η 2 ‐C 2 Me 2 )] 6 , [Ni(Me 2 Im) 2 (η 2 ‐COE)] 7 and [Ni(Me 2 Im Me ) 2 (η 2 ‐COE)] 8 (COE = cyclooctene). The reaction of trans ‐[Ni( i Pr 2 Im Me ) 2 Br 2 ] 2 with MeMgCl, EtMgBr or n BuLi leads to trans ‐[Ni( i Pr 2 Im Me ) 2 (CH 3 ) 2 ] 9 , trans ‐[Ni( i Pr 2 Im Me ) 2 (C 2 H 5 ) 2 ] 10 and trans ‐[Ni( i Pr 2 Im Me ) 2 ( n ‐C 4 H 9 ) 2 ] 11 . The reaction of 2 with i PrMgBr afforded minor amounts of [Ni( i Pr 2 Im Me ) 2 (η 2 ‐H 2 C=CHCH 3 )] 12 . Dicyanido complexes trans ‐[Ni( i Pr 2 Im) 2 (CN) 2 ] 13 , trans ‐[Ni( i Pr 2 Im Me ) 2 (CN) 2 ] 14 , trans ‐[Ni(Me 2 Im) 2 (CN) 2 ] 15 , and trans ‐[Ni(Me 2 Im Me ) 2 (CN) 2 ] 16 were prepared from reaction of the dihalide complexes 1 – 4 and trimethylsilyl cyanide.