Four- and Five-Coordinated Nickel(II) Isocyanide Complexes and Donor-Acceptor Complexes Containing Nickel and Mercury

Article abstract of DOI:10.1246/bcsj.64.3376

Reaction of NiI2(RNC)2 (1) (a: R = 2,6-Me2C6H3; b: 4-Br-2,6-Me2C6H2; c: 2,4-t-Bu2-6-MeC6H2; d: 2,4,6-t-Bu3C6H2) with RNC or PPh3 gave NiI2(RCN)3 (2) or NiI2(PPh3)(RNC)2 (3) (a: R = 2,6-Me2C6H3; b: 2,6-Me2-4-BrC6H2).An X-ray analysis of (3a) showed that the complex has a trigonal bipyramidal structure; crystal data: Space group Pna2₁; a = 21.577(2), b = 9.440(1), c = 17.075(1) Angstroem, α = β = γ = 90.0 deg, V = 3477.7(6) Angstroem³, R = 0.0444.The bromide and chloride complexes, NiX2(2,6-Me2C6H3NC)2 (1e: X = Cl; 1f: X = Br) did not produce five-coordinated species.When complexes (1a, 1b, 1e, or 1f) were treated with Hg in the presence of isocyanide, the donor-acceptor complexes 2 (X = I, Br, or Cl) (4) were formed.An X-ray analysis of (4b) (R = 4-Br-2,6-Me2C6H2) was undertaken; crystal data: Space group: P1/ (triclinic); a = 12.709(3), b = 16.145(3), c = 12.614(3) Angstroem, α = 96.11(2), β = 107.67(2), γ = 73.11(2) deg, V = 2359.5(10) Angstroem³, R = 0.0686.The complex is a donor-acceptor complex containing the Ni-Hg bond and has a dimeric structure bridged by two I atoms.The configuration around Ni is the trigonal bipyramid and around Hg, distorted tetrahedron.