End-to-End Azide-Bridged Manganese(III) Chain Compounds: Field-Induced Magnetic Phase Transitions and Variation of TC to 38 K Depending on the Side Groups of the Schiff Bases

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• 作者：Jung Hee Yoon ; Woo Ram Lee ; Dae Won Ryu ; Jin Wuk Lee ; Sung Won Yoon ; Byoung Jin Suh ; Hyoung Chan Kim ; Chang Seop Hong
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：November 7, 2011
• 年：2011
• 卷：50
• 期：21
• 页码：10777-10785
• 全文大小：1205K
• 年卷期：v.50,no.21(November 7, 2011)
• ISSN：1520-510X

文摘

Three one-dimensional coordination polymers [Mn(L)(N₃)]_n [L = L1 (1), L2 (2), L3 (3); L1H₂ = N,N鈥?bis(5-chlorosalicylideneiminato)-1,3-diaminopentane, L2H₂ = N,N鈥?bis(5-bromosalicylideneiminato)-1,3-diaminopentane, L3H₂ = N,N鈥?bis(5-bromosalicylideneiminato)-1,3-diamino-2-dimethylpropane] bridged by end-to-end azides were prepared. The crystal systems differ according to the Schiff bases used. Each Mn atom adopts a typical Jahn鈥揟eller distortion. The helicity of the chains occurs in a racemic manner only for 2. No noncovalent forces are relevant in 2, while 蟺鈥撓€ contacts are visible in 1 and 3. Magnetic measurements show the presence of apparent spin canting. Complexes 1 and 3 exhibit a field-induced metamagnetic transition from an antiferromagnetic state to a weak ferromagnetic phase, whereas 2 embraces a field-induced two-step magnetic phase transition. The critical temperature is observed at 38 K for 2, which is relatively higher than those for 1 (11 K) and 3 (10 K). The pronounced long-range order may contribute from intrachain exchange couplings and through-space dipolar interactions between adjacent chains.