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Modulating single-molecule magnet behavior towards multiple magnetic relaxation processes through structural variation in Dy4 clusters†
Inorganic Chemistry Frontiers ( IF 7 ) Pub Date : 2018-05-03 00:00:00 , DOI: 10.1039/c8qi00214b
Wen-Min Wang 1, 2, 3, 4, 5 , Xiao-Min Kang 4, 5, 6, 7 , Hai-Yun Shen 1, 2, 3, 4 , Zhi-Lei Wu 1, 2, 3, 4, 5 , Hong-Ling Gao 1, 2, 3, 4 , Jian-Zhong Cui 1, 2, 3, 4
Affiliation  

Three Dy4 clusters, [Dy4(tmhd)8(L)2(CH3OH)2]·CH3OH (1), [Dy4(hfac)8(L)2(DMF)2]·C7H16 (2) and [Dy4(dbm)6(L)23-OH)2]·CH2Cl2 (3) (tmhd = 2,2,6,6-tetramethyl-3,5-heptanedione, hfac = hexafluoroacetylacetonate, dbm = 1,3-diphenyl-1,3-propanedione, HL = 2-[(2-(hydroxyimino)propanehydrazide)methyl]), have been successfully synthesized by using three different β-diketonate salts (Dy(tmhd)3·2H2O, Dy(hfac)3·2H2O, and Dy(dbm)3·2H2O) to react with HL and by changing the solvent. The X-ray structural analysis shows that four DyIII ions in clusters 1 and 2 are linearly arranged; however, cluster 3 contains one Dy4 center with a rhombus-shaped arrangement. The different structures of three Dy4 clusters were profoundly affected by these minor changes in β-diketonate or a change in the solvent. Magnetic studies reveal that Dy4 clusters 1–3 exhibit different single-molecule magnet (SMM) behaviors under a zero dc field. 1 and 2 display slow magnetic relaxation behaviors with effective energy barriers ΔE/kB = 1.44 K for 1 and ΔE/kB = 50.96 K for 2, while for 3, two distinct slow magnetic relaxation processes are observed, with effective energy barriers ΔE/kB = 40.45 K for the fast relaxation process and ΔE/kB = 113.63 K for the slow relaxation process. This study shows that the β-diketonate coligands play an important role in modulating molecular structures and further affecting the magnetic dynamics of the lanthanide clusters towards multiple magnetic relaxation processes.

中文翻译:

通过Dy 4团簇的结构变化来调节单分子磁体朝向多种磁弛豫过程的行为

三个Dy 4簇,[Dy 4(tmhd)8(L)2(CH 3 OH)2 ]·CH 3 OH(1),[Dy 4(hfac)8(L)2(DMF)2 ]·C 7 ħ 162)和[镝4(DBM)6(L)2(μ 3 -OH)2 ]·CH 223)(tmhd = 2,2,6,6-四甲基-3,5-庚二酮,hfac =六氟乙酰丙酮酸酯,dbm = 1,3-二苯基-1,3-丙二酮,HL = 2-[((2-(羟基亚氨基))丙酰肼)]],已成功使用三种不同的β-二酮盐(Dy(tmhd)3 ·2H 2 O,Dy(hfac)3 ·2H 2 O和Dy(dbm)3 ·2H 2 O)合成与HL发生反应,并改变溶剂。X射线结构分析表明,簇1和簇2中的四个Dy III离子呈线性排列;但是,群集3包含一个Dy 4中心呈菱形排列。β-二酮的这些微小变化或溶剂的变化对三个Dy 4团簇的不同结构产生了深远的影响。磁性研究表明,Dy 41-3在零直流磁场下表现出不同的单分子磁体(SMM)行为。12显示慢磁弛豫行为与有效能垒Δ ë / ķ= 1.44 K代表1和Δ Ë / ķ= 50.96 K代表2,而对于3,观察到两个截然不同的慢磁弛豫过程,对于快速弛豫过程,有效能垒ΔE / k B = 40.45 K;对于慢弛豫过程,有效能垒ΔE / k B = 113.63K。这项研究表明,β-二酮丙酮酸大分子在调节分子结构和进一步影响镧系元素簇向多个磁弛豫过程的磁动力学方面起着重要作用。
更新日期:2018-05-03
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