Liu Lujia, DeGayner Jordan A, Sun Lei, Zee David Z, Harris T David
Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3113 , USA . Email:
Chem Sci. 2019 Mar 14;10(17):4652-4661. doi: 10.1039/c9sc00606k. eCollection 2019 May 7.
Materials with switchable magnetic and electrical properties may enable future spintronic technologies, and thus hold the potential to revolutionize how information is processed and stored. While reversible switching of magnetic order or electrical conductivity has been independently realized in materials, the ability to simultaneously switch both properties in a single material presents a formidable challenge. Here, we report the 2D manganese benzoquinoid framework (MeN)[MnII2(L)] (HL = 2,5-dichloro-3,6-dihydroxo-1,4-benzoquinone), as synthesized post-synthetic counterion exchange. This material is paramagnetic above 1.8 K and exhibits an ambient-temperature electrical conductivity of = 1.14(3) × 10 S cm ( = 0.74(3) eV). Upon soaking in a solution of sodium naphthalenide and 1,2-dihydroacenaphthylene, this compound undergoes a single-crystal-to-single-crystal (SC-SC) reduction to give Na(MeN)[MnL]. Structural and spectroscopic analyses confirm this reduction to be ligand-based, and as such the anionic framework is formulated as [MnII2(L˙)]. Magnetic measurements confirm that this reduced material is a permanent magnet below = 41 K and exhibits a conductivity value of = 2.27(1) × 10 S cm ( = 0.489(8) eV), representing a remarkable 200 000-fold increase over the parent material. Finally, soaking the reduced compound in a solution of [CpFe] affords Na(MeN)[MnII2(L)] a SC-SC process, with magnetic and electrical properties similar to those observed for the original oxidized material. Taken together, these results highlight the ability of metal benzoquinoid frameworks to undergo reversible, simultaneous redox switching of magnetic order and electrical conductivity.
具有可切换磁电性质的材料有望推动未来的自旋电子技术发展,从而有可能彻底改变信息的处理和存储方式。虽然材料中已分别实现了磁序或电导率的可逆切换,但在单一材料中同时切换这两种性质仍面临巨大挑战。在此,我们报道了通过合成后抗衡离子交换法制备的二维锰苯醌骨架化合物(MeN)[MnII2(L)](HL = 2,5-二氯-3,6-二羟基-1,4-苯醌)。该材料在1.8 K以上呈顺磁性,室温电导率为σ = 1.14(3) × 10 S cm(Ea = 0.74(3) eV)。将其浸泡在萘钠和1,2-二氢苊的溶液中,该化合物会发生单晶到单晶(SC-SC)还原反应,生成Na(MeN)[MnL]。结构和光谱分析证实这种还原反应基于配体,因此阴离子骨架可表示为[MnII2(L˙)]。磁性测量结果表明,这种还原后的材料在Tc = 41 K以下是永磁体,电导率值为σ = 2.27(1) × 10 S cm(Ea = 0.489(8) eV),相比母体材料显著提高了200000倍。最后,将还原后的化合物浸泡在[CpFe]溶液中,通过SC-SC过程可得到Na(MeN)[MnII2(L)],其磁电性质与原始氧化材料相似。综上所述,这些结果突出了金属苯醌骨架化合物能够实现磁序和电导率的可逆、同时氧化还原切换。