Abstract
“Xenophilic” complexes offer metal-metal bonds between disparate metal sites, but the nature of the metal-metal bonding is often unclear. Here, we describe two novel complexes with unsupported Fe−Fe bonds, LxFe−Fp (LX = β-aldiminate or β-diketiminate; Fp = Fe(CO)2Cp), that offer insight into Fe−Fe bonding. Mössbauer, magnetism, and DFT analysis indicate that the most accurate electronic structure description is LFeII←Fe0(CO)2Cp, in which the Fe(CO)2Cp is low-spin iron(0) and acts as an X-type ligand toward the high-spin iron(II) of the LFe fragment. This largely electrostatic interaction has a bond order of only 0.5. The three-coordinate high-spin iron(II) site has large zero-field splitting, and in addition its Mössbauer parameters can be used to rank the Fp− “metalloligand” as a donor; it is nearly as strong a donor as phosphides and alkyls.
Original language | English (US) |
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Article number | e202104431 |
Journal | Chemistry - A European Journal |
Volume | 28 |
Issue number | 11 |
DOIs | |
State | Published - Feb 19 2022 |
Externally published | Yes |
Keywords
- Iron
- magnetism
- metal-metal bonds
- xenophilic complexes
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Organic Chemistry