High temperature anionic Fe(III) spin crossover behavior in a mixed-valence Fe(II)/Fe(III) complex
Zhi-Jian Ouyang1, Xiao-Ying Mo1, Jia-Qi Ye1
1Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China. chenwb2018@gzhu.edu.cn dw320@aliyun.com.
Dalton Transactions (Cambridge, England : 2003)
|May 5, 2021
Summary
Two novel iron complexes were synthesized and characterized. Complex 2 exhibits high-temperature spin crossover (SCO) behavior, influenced by supramolecular interactions between its cation and anion components.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Crystallography
Background:
- Iron complexes are crucial in various chemical and biological processes.
- Understanding spin crossover (SCO) phenomena in iron complexes is vital for developing advanced materials.
- The ligand H3ATD (azotetrazolyl-2,7-dihydroxynaphthalene) offers unique coordination possibilities.
Purpose of the Study:
- To synthesize and structurally characterize two novel ion-pair iron(III) complexes using the H3ATD ligand.
- To investigate the magnetic properties and spin crossover behavior of the synthesized complexes.
- To elucidate the relationship between the molecular structure and the observed magnetic phenomena.
Main Methods:
- Synthesis of two ion-pair iron complexes: (PPh4)[FeIII(HATD)2]·2H2O (1) and [FeII(phen)3][FeIII(HATD)2]2·3DMA·3.5H2O (2).
- Single-crystal X-ray diffraction for detailed structural analysis of complexes 1 and 2.
- Variable-temperature magnetic susceptibility measurements to determine spin states and SCO behavior.
Main Results:
- Complexes 1 and 2 feature Fe(III) ions in octahedral coordination environments with the [FeIII(HATD)2]- core.
- Complex 1 exists in a low-spin state below 500 K.
- Complex 2 displays high-temperature spin crossover (SCO) between 360 and 500 K, driven by π-π stacking, hydrogen bonding, and Coulombic interactions.
Conclusions:
- The synthesized iron complexes exhibit distinct magnetic behaviors based on their structural arrangements.
- Supramolecular interactions within complex 2 are critical for its high-temperature spin crossover properties.
- This study provides insights into the design of iron complexes with tunable magnetic properties.
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