EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK.
Dalton Trans. 2018 Aug 29;47(34):11834-11842. doi: 10.1039/c8dt00685g.
A family of heterometallic Anderson-type 'wheels' of general formula MIII2MII5(hmp)124 (where MIII = Cr or Al and MII = Ni or Zn giving [Cr2Ni5] (1), [Cr2Zn5] (2), [Al2Ni5] (3) and [Al2Zn5] (4); hmpH = 2-pyridinemethanol) have been synthesised solvothermally. The metallic skeleton common to all structures describes a centred hexagon with the MIII sites disordered around the outer wheel. The structural disorder has been characterised via single crystal X-ray crystallography, 1-3D 1H and 13C solution-state NMR spectroscopy of the diamagnetic analogue (4), and solid-state 27Al MAS NMR spectroscopy of compounds (3) and (4). Alongside ESI mass spectrometry, these techniques show that structure is retained in solution, and that the disorder is present in both the solution and solid-state. Solid-state dc susceptibility and magnetisation measurements on (2) and (3) reveal the Cr-Cr and Ni-Ni exchange interactions to be JCr-Cr = -1 cm-1 and JNi-Ni,r = -5 cm-1, JNi-Ni,c = 10 cm-1. Fixing these values allows us to extract JCr-Ni,r = -1.2 cm-1, JCr-Ni,c = 2.6 cm-1 for (1), the exchange between adjacent Ni and Cr ions on the ring is antiferromagnetic and between Cr ions on the ring and the central Ni ion is ferromagnetic.
一种具有异金属安德森型“车轮”结构的配合物家族，其通式为MIII2MII5(hmp)124（其中 MIII=Cr 或 Al，MII=Ni 或 Zn，生成Cr2Ni5、Cr2Zn5、Al2Ni5和Al2Zn5；hmpH=2-吡啶甲醇），通过溶剂热法合成。所有结构中共同的金属骨架描述了一个中心六边形，MIII 位点在外轮周围无序排列。通过对顺磁性类似物（4）的单晶 X 射线晶体学、1-3D 1H 和 13C 溶液态 NMR 光谱学、化合物（3）和（4）的固态 27Al MAS NMR 光谱学对结构无序性进行了表征。除了 ESI 质谱法之外，这些技术表明结构在溶液中得以保留，而且无序存在于溶液和固态中。对（2）和（3）的固态直流磁化率和磁化强度测量表明，Cr-Cr 和 Ni-Ni 交换相互作用分别为 JCr-Cr=-1 cm-1 和 JNi-Ni,r=-5 cm-1，JNi-Ni,c=10 cm-1。固定这些值使我们能够提取（1）中相邻 Ni 和 Cr 离子之间的 JCr-Ni,r=-1.2 cm-1 和 JCr-Ni,c=2.6 cm-1，环上 Ni 和 Cr 离子之间的交换为反铁磁性，而环上 Cr 离子与中心 Ni 离子之间的交换为铁磁性。
