72918-80-0

Upstream product

• 1295-35-8 bis(1,5-cyclooctadiene)nickel ⁽⁰⁾ 
• 122-79-2 Phenyl acetate 

Downstream Products

• 14917-14-7 Ni(CO)2(2,2'-bipyridine) 
• 122-79-2 Phenyl acetate 

Relevant academic research and scientific papers

Reductive elimination of aryl carboxylates from acyl(aryloxy)nickel(II) and -palladium(II) complexes

Acyl(p-cyanophenoxy)nickel(II) and -palladium(II) complexes, M(COR)(OC6H4-p-CN)L2 (M = Ni, Pd; L2 = bpy, (PEt3)2), have been prepared by insertion reactions of CO into the metal-carbon bonds of the corresponding methylnickel(II) and -palladium(II) complexes. Addition of π-acids such as CO, maleic anhydride, and acrylonitrile selectively induces reductive elimination of p-cyanophenyl acetate from acylnickel(II) complexes, whereas thermolysis of the complexes mainly results in decarbonylation. In contrast, reductive elimination from the palladium analogue proceeds smoothly on thermolysis, and no apparent accelerating effect of added π-acids is observed. Kinetic studies of both reductive eliminations reveal that the former proceeds via an associative mechanism involving a five-coordinate intermediate, whereas the latter proceeds via two mechanisms, one being a dissociative pathway involving a three-coordinate species and the other being a direct reductive elimination from a four-coordinate species.

Preparation and Properties of Monoalkylnickel(II) Complexes Having a Phenoxo, Benzenethiolato, Oximato, β-Diketonato, or Halo Ligand

Thirteen complexes of a type NiR(Y)Ln (R=CH3 (Me), C2H5 (Et); Y=OC6H5, p-cyanophenoxo, p-phenylphenoxo, 8-quinolinolato, OCOEt, OCOPh, acetophenone oximato, acetylacetonato, benzoylacetonato, Cl; L=triethylphosphine (PEt3), 2,2'-bipyridine (bpy)) have been prepared by reactions of dialkylnickel(II) complexes NiR2L2 (1) with the corresponding active hydrogen compounds HY.Reactions of 1 with R'COY (Y=OC6H5, OCOC6H5, Cl) also afford the NiR(Y)Ln type complexes with formation of unsymmetrical ketones RCOR'.Reactions of 1 with alcohols lead to dehydrogenation of alcohols to afford aldehydes or ketones.The NIR(Y)Ln type complexes have be en characterized by elemental analysis and spectroscopies (IR, NMR, visible).NMR spectra of trans-NiMe(OCOPh)(PEt3)2, NiMe(acetophenone oximato)(PEt3) (11), NiMe(benzoylacetonato)(PEt3) show temperature dependence, indicating occurrence of rapid dynamic reactions on NMR time scale in these complexes.The acetophenone oximato ligand in 11 is proposed to serve as an oxa-, aza-?-allylic ligand on the bases of IR and NMR spectroscopies.NiEt(OCOC2H5)(bpy) (8), NiEt(OCOC6H5)(bpy), and NiEt(Cl)(bpy) (14) undergo disproportionation reaction to give NiEt2(bpy) and NiY2(bpy) type complexes.Diethyl ketone is also produced during the disproportionation of 8.Reactions of 14 with olefins having electron-withdrawing substituents afford NiCl2(bpy) and Ni(olefin)2(bpy).

Oxidative Addition of Aryl Carboxylates to Ni(0) Complexes Involving Cleavage of the Acyl-O Bond

Reactions of aryl carboxylates RCOO-p-C6H4X (R=CH3, C2H5, n-C3H7; X=H, CH3, OCH3, CN) with bis(1,5-cyclooctadiene)nickel, Ni(cod)2, in the presence of phosphine ligands yield olefin (R(-H)), p-XC6H4OH, and nickel carbonyl complex(es) when the R group has a β hydrogen, whereas CH4, C2H6, nichel carbonyl complex(es), and nickel phenoxide are formed when the R group is CH3.The formation of the products is accounted for by assuming oxidative addition of the ester to nickel involving the cleavage of the acyl-O bond of RCOO-p-C6H4X followed by decarbonylation of the acylnickel complex and decomposition of the alkylnickel complex: RCOO-p-C6H4X + NiLn -> RCONiLnOC6H4X -> RNiLnOC6H4X + CO.The intermediate alkyl(phenoxo)nickel-type complex NiCH3(OC6H5) was in fact isolated in the reaction of phenyl acetate with Ni(cod)2 in the presence of 2,2'-bipyridine.The rate of the reaction is first order with respect to the concentration of the zerovalent nickel complex and the pseudo-first-order rate constant increases with with the increase in the basicity of the phosphine ligand added and with the increase of the electron-withdrawing ability of X.On the basis of these results a mechanism involving a nucleophilic attack at the carbonyl carbon by nickel is proposed.The activation parameters for the reaction of C2H5COOC6H5 with the mixture of Ni(cod)2 and PPh3 are ΔH=21+/-2 kcal/mol, ΔS=-8.8+/-2.9 eu.