Thermal, magnetic, FTIR and XRD study of new Co(II) and Ni(II) theophyllinato complexes with benzylamine or ethanolamine

Article abstract of DOI:10.1023/A:1010177311508

Four new theophyllinato (th) complexes of Co(II) and Ni(II) were synthesized containing ethanolamine (2-aminoethanol, ea) or benzylamine (ba). Comprehensive FTIR speetroscopic, powder XRD, magnetic and thermal studies on these mixed ligand complexes have been carried out to get structural information. The almost identical FTIR spectra and XRD patterns of Co and Ni compounds with same composition have indicated that Co(th)₂(ba)2·2H₂O (1) and Ni(th)₂(ba)2·2H₂O (2) or Co(th)₂(ea)2 (3) and Ni(th)₂(ea)₂ (4) have very similar structure pair wise. The infrared spectra and X-ray diffraction patterns of thermally dehydrated 1 and 2 containing benzylamine have allowed only to suggest that the co-ordination number around the metal centres is four, while the high thermal stability of complexes 3 and 4 have indicated that they contain two of bidentate ethanolamine molecules in octahedral co-ordination. A big difference observed between the magnetic moments of Co compounds 1 and 3 have proven that the inner co-ordination sphere of complexes with benzylamine (1 and 2) is tetrahedral, whilst that with ethanolamine (3 and 4) is basically octahedral, independent of the cation centres (Co or Ni).