Immobilization of cobalt(III) Schiff base complexes onto Montmorillonite-K10: Synthesis, experimental and theoretical structural determination

• Novel Cobalt Schiff base complexes were prepared.
• The X-ray crystallography show that they are hexacoordinated in the solid state.
• Nanohybrid of the complexes and MMT clay were prepared via ion-exchange method.
• SEM and TEM show the resulting hybrid nanomaterials have layer structures.
• The structure of complexes were confirmed by theoretical calculation.

The [Co(naphophen)(PPh3)(OH2)]ClO4 and [Co(naphophen)(PBu3)(OH2)]BF4 (where naphophen = bis(naphthaldehyde)1,2-phenylenediimine) complexes were synthesized and chracterized by FT-IR, UV–Vis, 1H NMR, 13C NMR spectroscopy and elemental analysis techniques. The coordination geometry of the synthesized complexes were determined by X-ray crystallography. Cobalt (III) complexes have six-coordinated pseudo-octahedral geometry in which the O(1), O(2), N(1) and N(2) atoms of the Schiff base forms the equatorial plane. These complexes showed a dimeric structure via hydrogen bonding between the phenolate oxygen and the hydrogens of the coordinated H2O molecule. The theoretical calculations were also performed to optimize the structure of the complexes in the gas phase to confirm the structures proposed by X-ray crystallography. In addition, UV–Visible and IR spectra of complexes were calculated and compared with the corresponding experimental spectra to complete the experimental structural identification. The synthesized complexes were incorporated onto the Montmorillonite-K10 nanoclay via simple ion-exchange reaction. The structure and morphology of the obtained nanohybrids were identified by FT-IR, XRD, TGA/DTA, SEM and TEM techniques. Based on the XRD results of the new nanohybrid materials, the Schiff base complexes were intercalated in the interlayer spaces of clay. SEM and TEM micrographs of the clay/complex shows that the resulting hybrid nanomaterials has layer structures.

The [Co(naphophen)(PPh3)(OH2)]ClO4 and [Co(naphophen)(PBu3)(OH2)]BF4 complexes were synthesized and characterized by FT-IR, UV–Vis, 1H NMR, 13C NMR spectroscopy and elemental analysis techniques. The coordination geometry of synthesized complexes were determined by X-ray crystallography. The theoretical calculations were also performed to optimize the structure of complexes in the gas phase. The UV–Visible and IR spectra of complexes were calculated. The obtained complexes were incorporated into Montmorillonite-K10 nanoclay via simple ion-exchange reaction and were identified by FT-IR, XRD, TGA/DTA, SEM and TEM techniques..Figure optionsDownload as PowerPoint slide