Acid-Base Self-Assembly Chemistry and Hydrogen Bonding Interactions Resulting in the Formation of a Tetranuclear Aggregate Containing Four Crystallographically Non-Equivalent FeIII Centers
✍ Scribed by Stefania Tanase; Elisabeth Bouwman; Gary J. Long; Ahmed M. Shahin; Allison M. Mills; Anthony L. Spek; Jan Reedijk
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 229 KB
- Volume
- 2004
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
The synthesis and characterization of a mononuclear iron(III) complex [Fe(Hphpz)Cl(CH~3~OH)] (1) and a tetranuclear assembly of a bis(μ‐hydroxo)‐bridged dinuclear iron(III) complex [{Fe(Hphpz)~2~(OH)}~2~][Fe(Hphpz)~3~]~2~ (2) with the ligand 3(5)‐methyl‐5(3)‐(2‐hydroxyphenyl)pyrazole (H~2~phpz) is reported. Compound 1 is converted into 2 in a methanol solution and in the presence of a base. The asymmetric unit of 2 consists of two independent [Fe(Hphpz)~3~] molecules and one dinuclear complex [Fe(Hphpz)~2~(OH)]~2~ containing two crystallographically non‐equivalent iron(III) ions; the three units are linked by N−H···O and O−H···O hydrogen bonding and stacking interactions to form a cluster with an approximate C~2~‐symmetry. The Mössbauer spectra of [{Fe(Hphpz)~2~(OH)}~2~][Fe(phpz)~3~]~2~ have been measured at 295 and 78 K and indicate the presence of four crystallographically distinct, but chemically similar iron(III) sites. The magnetic properties of this compound originate from the weak antiferromagnetic interaction between the Fe^III^ ions of the [Fe(phpz)~2~(OH)]~2~ dimer (J = −2.8 cm^−1^). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)