Synthesis of Well‐Defined Bicapped Octahedral Iron Clusters [(trenL)2Fe8(PMe2Ph)2]n (n=0, −1) |
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| Authors: | Raúl Hernández Sánchez Alexander M. Willis Shao‐Liang Zheng Prof. Theodore A. Betley |
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| Affiliation: | Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St. Cambridge, MA, 02138 USA |
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| Abstract: | The synthesis of polynuclear clusters with control over size and cluster geometry remains an unsolved challenge. Herein, we report the synthesis and characterization of open‐shell octairon clusters supported by two heptaamine ligands [o‐H2NC6H4NH(CH2)2]3N (trenLH9). The crystal structure of the all‐ferrous species ([trenL)2Fe8(PMe2Ph)2] ( 1 ) displays a bicapped octahedral geometry with Fe? Fe distances ranging from 2.4071(6) to 2.8236(5) Å, where the ligand amine units are formally in amine, amide, and imide oxidation states. Several redox states of the octairon cluster are accessible, as ascertained using cyclic voltammetry. The one‐electron‐reduced clusters [M]+[(trenL)2Fe8(PMe2Ph)2]? (M=Bu4N ( 2 a ); (15‐crown‐5)Na(thf) ( 2 b )) were isolated and characterized. Variable‐temperature magnetic susceptibility data indicates that the exchange coupling within the [Fe8] core is antiferromagnetic which is attenuated upon reduction to the mixed valent anion. |
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| Keywords: | cluster compounds cyclic voltammetry iron magnetic properties structure elucidation |
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