Synthesis, structure, and single-molecule magnet property of a mixed cyanide-oxo-bridged {FeIII2FeII2} complex featuring pentagonal bipyramidal Fe(II) centers

IF 4.7 2区化学 Q2 CHEMISTRY, PHYSICAL

Journal of Molecular Structure Pub Date : 2025-09-29 DOI:10.1016/j.molstruc.2025.144209

Fu-Xing Shen , Kun-Hua Zhang , Ao-Na Sun , Jiong Yang , Dong Shao

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Abstract

The first cyanide-oxo-bridged tetranuclear {Fe^III₂Fe^II₂} complex, {[(Tp*)Fe^III(CN)₃][Fe^II(tdmmb)]O}₂·H₂O·3MeOH (Fe₄) (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate, tdmmb = 1,3,10,12-tetramethyl-1,2,11,12-tetra-aza[[3](2,6)pyridino[3](2,9)-1,10-phenanthrolinophan-2,10-diene) was prepared and structurally and magnetically characterized. Structural characterization of the tetranuclear molecule reveals an uncommon structure in which a pentagonal bipyramidal iron(II) sites (S = 2) are connected by one single O^2- bridge and further the Fe(II) dimer are bridged terminally by two tricyanoferrate(III) anions (S = 1/2). Magnetic susceptibility reveals antiferromagnetic coupling between Fe³⁺-CN-Fe²⁺ and Fe²⁺-O-Fe²⁺ centers, with the coupling constants of J_{Fe(III)/Fe(II)} = -4.8 cm⁻¹ and J_{Fe(II)/Fe(II)} = -11.2 cm⁻¹, to give an S = 5 ground state. This Fe₄ molecule was found to exhibit the single-molecule magnet (SMM) behavior with the effective energy barrier U_eff = 38.2 K. Furthermore, an open magnetic hysteresis loop was observed for the compound. This work provides not only a rare cyanide-oxo mixed bridged complex but also suggest pentagonal bipyramidal Fe(II) building block represents a promising avenue to create high-performance single molecule magnets.

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具有五角形双锥体Fe（II）中心的混合氰化物-氧桥接{feii2feii2}配合物的合成、结构和单分子磁性能

制备了第一个氰化物-氧桥接的四核{FeIII2FeII2}配合物{[(Tp*)FeIII(CN)3][FeII(tdmmb)]O}2·H2O·3MeOH (Fe4) （Tp* =氢化（3,5-二甲基吡唑）硼酸盐，tdmmb = 1,3,10,12-四甲基-1,2,11,12-四氮杂[[3]（2,6）吡啶[3](2,9)-1,10-菲罗啉-2,10-二烯），并对其进行了结构和磁性表征。四核分子的结构表征揭示了一种罕见的结构，其中一个五边形双锥体铁（II）位点（S = 2）由一个O2-桥连接，并且铁（II）二聚体末端由两个三氰铁酸盐（III）阴离子（S = 1/2）桥接。磁化率表明Fe3+-CN-Fe2+和Fe2+-O-Fe2+中心之间存在反铁磁耦合，耦合常数为JFe(III)/Fe(II) = -4.8 cm−1和JFe(II)/Fe(II) = -11.2 cm−1，基态为S = 5。该Fe4分子表现出单分子磁体（SMM）行为，有效能垒Ueff = 38.2 K。此外，该化合物还观察到一个开放的磁滞回线。这项工作不仅提供了一种罕见的氰化物-氧混合桥接配合物，而且表明五边形双锥体铁（II）构建块代表了一种有前途的途径来制造高性能的单分子磁体。

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来源期刊

Journal of Molecular Structure 化学-物理化学

CiteScore

7.10

自引率

15.80%

发文量

2384

审稿时长

45 days

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