Further iminopyrrolyl complexes of nickel, cobalt, iron and copper: Synthesis and structural characterisation

• Reaction of sodium 2-iminopyrrolyls with metal halides gave new metal complexes.
• Fe(II) TBP complexes with two iminopyrrolyl and a pyridine ligand are obtained.
• Homoleptic Co(II) tetrahedral complexes with two iminopyrrolyl ligands are obtained.
• Homoleptic Ni(II) SP complexes with two iminopyrrolyl ligands are obtained.
• Cu(I) and Cu(II) complexes with one or two iminopyrrolyl ligands are obtained.

The reaction between two equivalents of 2-(N-arylformimino)pyrrolyl sodium salts (NaNC4H3C(H) = N-Ar), with Ar = C6H5 (I), 2,6-iPr2-C6H3 (II) or 2-(N-arylformimino)phenanthro[9,10-c]pyrrolyl sodium salts (NaNC16H10C(H)N-Ar), with ArC6H5 (III), 2,6-iPr2-C6H3 (IV) and one equivalent of nickel(II), cobalt(II), iron(II) and copper(I) halides, in THF, at low temperatures, afforded bis(iminopyrrolyl) or bis(iminophenanthro[9,10-c]pyrrolyl) complexes with different geometries around the metal centres. Nickel(II) derivatives displayed distorted square planar geometries, whereas for cobalt a tetrahedral complex is proposed. The reactions with FeCl2 resulted in very unstable products, giving rise to dimers with pentacoordinated Fe(III) centres. The addition of two equivalents of pyridine to the reaction medium improved the stability of the resulting compound, enabling the formation of a 16-electron Fe(II) complex, which contained simultaneously two iminopyrrolyls and also a pyridine ligand. In the reaction of CuBr with 2-(N-2,6-diisopropylphenylformimino)pyrrolyl sodium salt, a complex with the general formulation [Cu(iminopyrrolyl)]x was obtained. When exposed to the air, this complex gives rise to the corresponding bis(iminopyrrolyl) Cu(II) complex.

A series of 2-(N-arylformimino)pyrrolyl complexes of Fe, Co, Ni and Cu is synthesised and characterised by elemental analysis, mass spectrometry, NMR and X-ray diffraction.Figure optionsDownload as PowerPoint slide