| 18698441 |
Jones C, Mills DP, Rose RP, Stasch A: Synthesis and structural characterisation of group 10 metal (II) gallyl complexes: analogies with platinum diboration catalysts?. Dalton Trans. 2008 Sep 7;(33):4395-408. Epub 2008 Jul 3.
Reactions of the anionic gallium (i) heterocycle, [:Ga{[N (Ar) C (H)](2)}](-) (Ar = C (6) H (3) Pr (i)(2)-2,6), with a variety of mono- and bidentate phosphine, tmeda and 1,5-cyclooctadiene (COD) complexes of group 10 metal dichlorides are reported. In most cases, salt elimination occurs, affording either mono (gallyl) complexes, trans-[MCl{Ga{[N (Ar) C (H)](2)}}(PEt (3))(2)] (M = Ni or Pd) and cis-[PtCl{Ga{[N (Ar) C (H)](2)}}(L)] (L = R (2) PCH (2) CH (2) PR (2), R = Ph (dppe) or cyclohexyl (dcpe)), or bis (gallyl) complexes, trans-[M{Ga{[N (Ar) C (H)](2)}}(2)(PEt (3))(2)] (M = Ni, Pd or Pt), cis-[Pt{Ga{[N (Ar) C (H)](2)}}(2)(PEt (3))(2)], cis-[M{Ga{[N (Ar) C (H)](2)}}(2)(L)] (M = Ni, Pd or Pt; L = dppe, Ph (2) CH (2) PPh (2) (dppm), tmeda or COD). The crystallographic and spectroscopic data for the complexes show that the trans-influence of the gallium (i) heterocycle lies in the series, B (OR)(2) > H (-) > PR (3) approximately [:Ga{[N (Ar) C (H)](2)}](-) > Cl (-). Comparisons between the reactivity of one complex, [Pt{Ga{[N (Ar) C (H)](2)}}(2)(dppe)], with that of closely related platinum bis (boryl) complexes indicate that the gallyl complex is not effective for the catalytic or stoichiometric gallylation of alkenes or alkynes. The phosphaalkyne, Bu (t) C [triple bond, length as m-dash] P, does, however, insert into one gallyl ligand of the complex, leading to the novel, crystallographically characterised P,N-gallyl complex, [Pt{Ga{[N (Ar) C (H)](2)}}{Ga{PC (Bu (t)) C (H)[N (Ar)] C (H) N (Ar)}}(dppe)]. An investigation into the mechanism of this insertion reaction has been undertaken. |
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