Metal derivatives of azoles. Part 4. Platinum(II) and palladium(II) complexes

Abstract

The reaction of [MCl₂(L–L)][M = Pd or Pt, L–L = 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis(diphenylarsino)ethane (dpae), 2,2′-bipyridine (bipy), or cyclo-octa-1,5-diene (cod)] with alkali and an azole [pyrazole (Hpz), 3,5-dimethylpyrazole (3,5Me₂-Hpz), indazole, or tetrazole] or with a potassium pyrazolate gives the [M(azolate-N)₂(L–L)] complexes, where the azolato-ligands are unidentate. While I₂ or HCl cleaves the metal–nitrogen bonds, the reaction with HBF₄ acid affords either mono- or bi-nuclear cations, [M(azole)₂(L–L)]²⁺ or [(L–L)M(µ-pyrazolato-NN′)₂M(L–L)]²⁺ respectively; the latter compounds contain esobidentate pyrazolato-ligands.