Controlling assembly and single-molecule magnet behavior of Fe-Ni clusters utilizing steric effect

• Published in: Inorganic chemistry communications 2018-07, Vol.93, p.87-91
• Main Authors: Jiao, Yu-Shu, Jiao, Cheng-Qi, Meng, Yin-Shan, Liu, Xue-Ru, Zhao, Liang, Liu, Tao
• Format: Article
• Language: English
• Subjects: Cyanide bridge; Ferromagnetic interactions; Single-molecule magnets; Steric effect; Tunable assembly
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2018.05.015

Utilizing the building block [(TpR)FeIII(CN)3]− featuring different steric hindrance, a trinuclear [NiII(4-Clbpy)2][(pzTp)FeIII(CN)3]2·4H2O (1) (pzTp = tetrakis(pyrazolyl)borate; 4‑Clbpy = 4‑chlorine‑2,2′‑dibipyridine) and a tetranuclear {[NiII(4-Clbpy)2][(Tp*)FeIII(CN)3]}2·4CH3OH·2H2O (2) (Tp* = hydrotris(3,5‑dimethylpyrazolyl)borate) were successfully synthesized. Magnetic studies revealed that both compound 1 and 2 exhibited intramolecular ferromagnetic interaction. Dynamic susceptibility study indicated that compound 2 exhibited slow magnetic relaxation. The relaxation energy barrier was Δ/kB = 62.31 K with the pre-exponential factor of τ0 = 2.87 × 10−10 s. In addition, compound 2 can exhibit hysteresis at 1.8 K. A trinuclear cyanide-bridged FeIII2NiII cluster [NiⅡ(Clbpy)2][(pzTp)FeⅢ(CN)3]2▪4H2O(1) and a tetranuclear cyanide-bridged FeIII2NiII2 cluster {[NiⅡ(Clbpy)2][(Tp*)FeⅢ(CN)3]}▪4CH3OH▪2H2O (2) were synthesized. Magnetic measurements indicated that both compound 1 and 2 exhibited ferromagnetic interaction, but compound 2 behaves as the single-molecule magnet. [Display omitted] •A trinuclear FeIII2NiII cluster and a tetranuclear FeIII2NiII2 were synthesized.•Compound 1 and 2 exhibits ferromagnetic interaction but compound 2 behaves as SMMs.•It provides a strategy to control nuclearity and magnetism utilizing steric effect.