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<p>Reactions of ferrous or ferric sulphates with the chelating diamine ligands <i>bpy</i> (2,2'-bipyridine) and <i>phen</i> (1,10-phenanthroline) in methanol/water solution yielded two new complexes, a green Fe<sup>III</sup> complex [Fe<sub>2</sub>(<i>bpy</i>)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>O(SO<sub>4</sub>)<sub>2</sub>]·3H<sub>2</sub>O <b>1</b> and dark red complex [Fe(<i>phen</i>)<sub>3</sub>](SO<sub>4</sub>)·8.4H<sub>2</sub>O <b>2</b>. Both complexes were characterized using chemical and spectroscopic methods (IR, UV–Vis). Single-crystal X-ray study showed that <b>1</b> exhibits molecular structure formed of dinuclear complex molecules comprising {Fe–O–Fe} structural unit with close distance between the deformed octahedrally coordinated Fe atoms (3.1857(8) Å) and the unit cell content is completed by water solvate molecules. The crystal structure of <b>2</b> is ionic and is formed of [Fe(<i>phen</i>)<sub>3</sub>]<sup>2+</sup> complex cation, sulphate anion and water solvate molecules. The temperature dependent magnetic study of dinuclear complex <b>1</b> revealed strong antiferromagnetic interaction between the two Fe<sup>III</sup> atoms which both are in HS state at all temperatures. The theoretical calculations predict strong antiferromagnetic interaction in dimers, and the analysis of magnetic data yields <i>J/k</i><sub><i>B</i></sub> = −315.4&#xa0;K. The thermal behaviour of both complexes <b>1</b> and <b>2</b> was studied in both oxidative (air) and inert (nitrogen) atmospheres. The thermal decomposition in all cases started with dehydration at 90&#xa0;°C <b>1</b> and 80&#xa0;°C <b>2</b>; the dehydrations were followed by temperature dependent IR spectroscopy for complex <b>2</b>. In both atmospheres, the solid residues consisted of nanosized oxides (α-Fe<sub>2</sub>O<sub>3</sub>), as corroborated by scanning electron microscopy, while energy-dispersive X-ray spectroscopy confirmed the homogeneity of the resulting oxides.</p>

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Iron(II) and iron(III) complexes with sulphate anion or ligand, their thermal behaviour and magnetic properties

  • 期刊论文

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  • 发表日期：

    2025年7月29日

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  • Miroslava Matiková Maľarová,
  • Jana Tomičová,
  • Juraj Kuchár,
  • Erika Samolova,
  • Erik Čižmár,
  • Jaroslav Briančin,
  • Juraj Černák

摘要

Reactions of ferrous or ferric sulphates with the chelating diamine ligands bpy (2,2'-bipyridine) and phen (1,10-phenanthroline) in methanol/water solution yielded two new complexes, a green FeIII complex [Fe2(bpy)2(H2O)2O(SO4)2]·3H2O 1 and dark red complex [Fe(phen)3](SO4)·8.4H2O 2. Both complexes were characterized using chemical and spectroscopic methods (IR, UV–Vis). Single-crystal X-ray study showed that 1 exhibits molecular structure formed of dinuclear complex molecules comprising {Fe–O–Fe} structural unit with close distance between the deformed octahedrally coordinated Fe atoms (3.1857(8) Å) and the unit cell content is completed by water solvate molecules. The crystal structure of 2 is ionic and is formed of [Fe(phen)3]2+ complex cation, sulphate anion and water solvate molecules. The temperature dependent magnetic study of dinuclear complex 1 revealed strong antiferromagnetic interaction between the two FeIII atoms which both are in HS state at all temperatures. The theoretical calculations predict strong antiferromagnetic interaction in dimers, and the analysis of magnetic data yields J/kB = −315.4 K. The thermal behaviour of both complexes 1 and 2 was studied in both oxidative (air) and inert (nitrogen) atmospheres. The thermal decomposition in all cases started with dehydration at 90 °C 1 and 80 °C 2; the dehydrations were followed by temperature dependent IR spectroscopy for complex 2. In both atmospheres, the solid residues consisted of nanosized oxides (α-Fe2O3), as corroborated by scanning electron microscopy, while energy-dispersive X-ray spectroscopy confirmed the homogeneity of the resulting oxides.