Ahmed Manan, Zenere Katrina A, Sciortino Natasha F, Arachchige Kasun S A, Turner Gemma F, Cruddas Jace, Hua Carol, Price Jason R, Clegg Jack K, Valverde-Muñoz Francisco Javier, Real Jose A, Chastanet Guillaume, Moggach Stephen A, Kepert Cameron J, Powell Benjamin J, Neville Suzanne M
The School of Chemistry, UNSW Sydney, Sydney 2052, New South Wales, Australia.
The School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia.
Inorg Chem. 2022 May 2;61(17):6641-6649. doi: 10.1021/acs.inorgchem.2c00530. Epub 2022 Apr 20.
We investigate the effects of a broad array of external stimuli on the structural, spin-crossover (SCO) properties and nature of the elastic interaction within the two-dimensional Hofmann framework material [Fe(cintrz)Pd(CN)]·guest (cintrz = -cinnamalidene 4-amino-1,2,4-triazole; ·guest; guest = 3HO, 2HO, and Ø). This framework exhibits a delicate balance between ferro- and antiferro-elastic interaction characters; we show that manipulation of the pore contents across guests = 3HO, 2HO, and Ø can be exploited to regulate this balance. In ·3HO, the dominant antiferroelastic interaction character between neighboring Fe sites sees the low-temperature persistence of the mixed spin-state species {HS-LS} for {Fe1-Fe2} (HS = high spin, LS = low spin). Elastic interaction strain is responsible for stabilizing the {HS-LS} state and can be overcome by three mechanisms: (1) partial (2HO) or complete (Ø) guest removal, (2) irradiation via the reverse light-induced excited spin-state trapping (LIESST) effect (λ = 830 nm), and (3) the application of external hydrostatic pressure. Combining experimental data with elastic models presents a clear interpretation that while guest molecules cause a negative chemical pressure, they also have consequences for the elastic interactions between metals beyond the simple chemical pressure picture typically proposed.
我们研究了一系列外部刺激对二维霍夫曼骨架材料[Fe(cintrz)Pd(CN)]·客体（cintrz = -肉桂叉基-4-氨基-1,2,4-三唑；·客体；客体 = 3HO、2HO和Ø）的结构、自旋交叉（SCO）性质以及弹性相互作用本质的影响。该骨架在铁弹性和反铁弹性相互作用特征之间展现出微妙的平衡；我们表明，通过改变客体为3HO、2HO和Ø时的孔内容物，可以利用这种方式来调节这种平衡。在·3HO中，相邻铁位点之间占主导的反铁弹性相互作用特征使得{Fe1-Fe2}的混合自旋态物种{HS-LS}（HS = 高自旋，LS = 低自旋）在低温下持续存在。弹性相互作用应变负责稳定{HS-LS}状态，并且可以通过三种机制来克服：（1）部分（2HO）或完全（Ø）去除客体，（2）通过反向光诱导激发自旋态捕获（LIESST）效应（λ = 830 nm）进行辐照，以及（3）施加外部静水压力。将实验数据与弹性模型相结合，给出了一个清晰的解释，即虽然客体分子会产生负化学压力，但它们对金属之间弹性相互作用的影响超出了通常提出的简单化学压力图景。
