A Ferric Semiquinoid Single-Chain Magnet via Thermally-Switchable Metal-Ligand Electron Transfer

作者：DeGayner, Jordan A.; Wang, Kunyu; Harris, T. David^*

来源：Journal of the American Chemical Society, 2018, 140(21): 6550-6553.

DOI：10.1021/jacs.8b03949

• VALENCE TAUTOMERISM
• MIXED-VALENCE
• COORDINATION POLYMERS
• IRON COMPLEXES
• COBALT
• EXCHANGE
• BEHAVIOR
• SERIES
• CONDUCTIVITY
• COERCIVITY

We report the synthesis of a semiquinoid-bridged single-chain magnet, as generated through a thermally induced metal ligand electron transfer. Reaction of FeCl3 with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (LH2) in the presence of (NMe4)Cl gave the compound (NMe4)(2)[LFeCl2]. Together, variable-temperature X-ray diffraction, Mossbauer spectra, Raman spectra, and dc magnetic susceptibility reveal a transition from a chain containing (L2-)Fe-II units to one with (L3-center dot)Fein upon decreasing temperature, with a transition temperature of T-1/2 = 213 K. The dc magnetic susceptibility measurements show strong metal radical coupling within the chain, with a coupling constant of J = -81 cm(-1), and ac susceptibility data reveal slow magnetic relaxation, with a relaxation barrier of Delta(tau) = 55(1) cm(-1). To our knowledge, this compound provides the first example of a semiquinoid-bridged single-chain magnet.

• 出版日期2018-5-30
• 单位西北大学; 南开大学