Zhang Jun, Kosaka Wataru, Sato Hiroyasu, Miyasaka Hitoshi
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan.
Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
J Am Chem Soc. 2021 May 12;143(18):7021-7031. doi: 10.1021/jacs.1c01537. Epub 2021 Apr 14.
Changing nonmagnetic materials to spontaneous magnets is an alchemy-inspiring concept in materials science; however, it is not impossible. Here, we demonstrate chemical modification from a nonmagnet to a bulk magnet of either a ferrimagnet or antiferromagnet, depending on the adsorbed guest molecule, in an electronic-state-flexible layered metal-organic framework, [{Ru(2,4-FPhCO)}TCNQ(EtO)] (; 2,4-FPhCO = 2,4-difluorobenzoate; TCNQ(EtO) = 2,5-diethoxy-7,7,8,8-tetracyanoquinodimethane). The guest-free paramagnet undergoes a thermally driven intralattice electron transfer involving a structural transition at 380 K. This charge modification can also be implemented by guest accommodations at room temperature; adsorbs several organic molecules, such as benzene (PhH), -xylene (PX), 1,2-dichloroethane (DCE), dichloromethane (DCM), and carbon disulfide (CS), forming with intact crystallinity. This induces an intralattice electron transfer to produce a ferrimagnetically ordered magnetic layer. According to the interlayer environment tuned by the corresponding guest molecule, the magnetic phase is consequently altered to a ferrimagnet for the guests PhH, PX, DCE, and DCM or an antiferromagnet for CS. This is the first demonstration of the postsynthesis of bulk magnets using guest-molecule accommodations.
将非磁性材料转变为自发磁体是材料科学中一个激发人们对炼金术幻想的概念；然而，这并非不可能。在此，我们展示了在一种电子态灵活的层状金属有机框架[{Ru(2,4 - FPhCO)}TCNQ(EtO)]（其中2,4 - FPhCO = 2,4 - 二氟苯甲酸酯；TCNQ(EtO) = 2,5 - 二乙氧基 - 7,7,8,8 - 四氰基对苯二醌二甲烷）中，根据吸附的客体分子，将非磁体化学改性为铁磁体或反铁磁体的块状磁体。无客体的顺磁体在380 K时经历热驱动的晶格内电子转移，伴随结构转变。这种电荷改性也可以在室温下通过客体容纳来实现；它吸附几种有机分子，如苯（PhH）、对二甲苯（PX）、1,2 - 二氯乙烷（DCE）、二氯甲烷（DCM）和二硫化碳（CS），形成具有完整结晶度的产物。这引发晶格内电子转移以产生铁磁有序的磁性层。根据相应客体分子调节的层间环境，磁相相应地转变为对于客体PhH、PX、DCE和DCM为铁磁体，对于CS为反铁磁体。这是首次展示利用客体分子容纳进行块状磁体的后合成。
