Synthesis and structural studies on trivalent lanthanide 2-acetylpyridine-2-furoylhydrazone complexes

Summary Two types of M(Hapfh)₂Cl]Cl₂ and M(apfh)₂OH] complexes; Hapfh=2-acetylpyridine-2-furoylhydrazone M=La^III, Pr^III, Nd^III, Eu^III or Dy^III], possessing the neutral and deprotonated ligand respectively, have been prepared and characterised by elemental analysis, molar conductance, magnetic susceptibility measurements, electronic, i.r. and n.m.r. (¹H and¹³C) spectral studies. The nephelauxetic ratio ( ), covalency () and bonding parameter (b^1/2) have been calculated for the Nd^III complexes. I.r. spectral studies reveal that Hapfh acts as a neutral tridentate in M(Hapfh)₂Cl]Cl₂ and uninegative tridentate in M(apfh)₂OH]. A coordination number of seven around the metal ions is proposed.