Reactions of low-valent metal complexes with fluorocarbons. Part XII. Fluoro-olefin reactions of zerovalent nickel complexes

Abstract

Bis(cyclo-octa-1,5-diene)nickel reacts with perfluoropropene to give (1,5-C₈H₁₂)Ni(C₃F₆)(I), which reacts with triphenyl- or triethyl-phosphine to afford (Ph₃P)₂Ni(C₃F₆)(IIa) and (Et₃P)₂Ni(C₃F₆)(IIb), respectively. The zerovalent nickel compounds (1,5-C₈H₁₂)(Et₃P)₂Ni, (1,5-C₈H₁₂)[(Buⁿ)₃P]₂Ni, [(Ph₂PCH₂)₂][(Buⁿ)₃P]₂Ni, (Et₃P)₄Ni, and (Ph₂PMe)₄Ni, react with tetrafluoroethylene to give the stable crystalline octafluoronickelacyclopentane complexes L₂Ni(CF₂)₄(L = Et₃P, Buⁿ₃P, or Ph₂PMe; or L₂= Ph₂PCH₂CH₂PPh₂). These complexes readily undergo ligand-exchange reactions, and by treatment with 2,2′-bipyridyl or cyclo-octa-1,5-diene and zinc bromide give, in certain cases, the crystalline derivatives C₁₀H₈N₂Ni(CF₂)₄(VIII) and (1,5-C₈H₁₂)Ni(CF₂)₄(IX). The diene ligand in the latter can be displaced with triphenylphosphine or γ-picoline to give (Ph₃P)₂Ni(CF₂)₄ and (γ-picoline)₂Ni(CF₂)₄, respectively. Treatment of (1,5-C₈H₁₂)₂Ni with C₂F₄ gives an unstable compound, which on addition of Ph₂PMe or Et₃P gave L₂Ni(CF₂)₄. The compound [(MeO)₃P]₂Ni(CF₂)₄,½C₆H₆ is obtained from tetrafluoroethylene and tetrakis(trimethyl phosphite)nickel, and tetrakis(methyldiphenylphosphine)nickel reacts with trifluoroethylene to give (Ph₂PMe)₂Ni(C₂F₃H)₂.