Synthesis and characterization of lanthanide complexes prepared with 2-((E)-(1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol |
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| Authors: | Abubak’r Abrahams Tatenda Madanhire Eric Hosten Richard Betz |
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| Institution: | 1. Department of Chemistry, Nelson Mandela Metropolitan University, Port Elizabeth, South AfricaAbubakr.Abrahams@nmmu.ac.za;3. Department of Chemistry, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa |
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| Abstract: | Rare-earth complexes of the general formula Ln(H2L1)2(NO3)3] Ln = Gd (1), Ho (2) or Nd (3)] were prepared from an o-vanillin derived Schiff base ligand, 2-((E)-(1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol (H2L1). The single-crystal X-ray diffraction studies and SHAPE analyses of the Gd(III) and Ho(III) complexes show that the complexes are ten-coordinate and exhibit distorted tetradecahedron geometries. The phenolate oxygen-bridged dinuclear complex, Ce2(H2L1)(ovan)3(NO3)3] (4, ovan = monodeprotonated o-vanillin), was obtained from the reaction of Ce(NO3)3?6H2O with H2L1. X-ray analysis revealed that hydrolysis of H2L1 occurred to yield o-vanillin, which bridged two cerium atoms with the Ce?Ce distance equal to 3.8232(6) Å. The Ce(III) ions are both ten-coordinate, but have different coordination environments, showing tetradecahedron and staggered dodecahedron geometries, respectively. With proton migration occurring from the phenol group to the imine function, complexation of the lanthanides to the ligand gives the Schiff base a zwitterionic phenoxo-iminium form. |
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| Keywords: | Lanthanide bidentate crystal structure Schiff base o-vanillin |
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