基于[Dy_4(μ_4-O)]四面体结构单元的八核和十核镝簇合物的合成、结构及其单分子磁体行为研究  

Synthesis, Structures and Single-Molecule Magnet Behaviour of Octanuclear and Decanuclear Dysprosium Clusters Based on [Dy_4(μ_4-O)] Tetrahedral Subunits

作　　者：郭鹏虎 廖小芬 冷际东[1] 童明良[1] 

机构地区：[1]生物无机与合成化学教育部重点实验室光电材料与技术国家重点实验室中山大学化学与化学工程学院,广州510275

出　　处：《化学学报》2013年第2期173-178,共6页Acta Chimica Sinica

基　　金：973计划(No.2012CB821704);国家自然科学基金(Nos.91122032;90922009;21121061)资助~~

摘　　要：通过溶剂热法合成了两个稀土簇合物,其组成分别为:[Dy8(bpt)8(μ4-O)2(μ-OMe)8(μ1,1,3,3-N3)(μ1,3-N3)(N3)2]11H2O 9MeOH(1)和[Dy10(bpt)6(μ4-O)4(μ3-OMe)4(μ-OMe)8(μ-OAc)2(OAc)2]40H2O(2)(Hbpt=3,5-双(2-吡啶基)-1,2,4-三氮唑).1的簇核结构由两个[Dy4(μ4-O)]四面体通过罕见的μ1,1,3,3和μ1,3叠氮桥连接而成,2则由四个共边连接的[Dy4(μ4-O)]四面体组成.两个簇合物都表现出单分子磁体行为,其中2是核数最高的纯稀土单分子磁体.Two novel [Dy4（μ4-O）] based dysprosium（Ⅲ） clusters,namely,[Dy8（bpt）8（μ4-O）2（μ-OMe）8（μ1,1,3,3-N3）（μ1,3-N3）（N3）2] 11H2O 9MeOH（1） and [Dy10（bpt）6（μ4-O）4（μ3-OMe）4（μ-OMe）8（μ-OAc）2（OAc）2] 40H2O（2）（Hbpt=3,5-bis（pyridin2-yl）-1,2,4-trizole）,are synthesized successfully.To obtain complex 1,a mixture of DyCl3（0.1 mmol）,2,2’-Hbpt（0.1 mmol） and NaN3（0.15 mmol） was sealed in a 25 mL vessel and then heated at 160 ℃ in methanol condition（8 mL） for 72 h.The reaction of Dy（OAc）3（0.17 mmol） and 2,2’-Hbpt（0.1 mmol） under the same condition as complex 1 yielded complex 2.Single-crystal X-ray diffraction reveals that complex 1 consists of a pair of [Dy4（μ4-O）] tetrahedral units bridged by two azido groups in μ1,1,3,3 and μ1,3 modes as well as two bpt ligands,while complex 2 possesses four edge-sharing [Dy4（μ4-O）] tetrahedral units.Magnetic susceptibility of polycrystalline samples were carried out using a SQUID magnetometer in the temperature range 2～300 K at 500 Oe dc field.The χMT value are 107.8 cm3 K mol-1for complex 1 and 133.6 cm3 K mol-1 for complex 2 at 300 K,which are close to the expected values.The maximum values of magnetization at 1.8 K are 40.81 Nβ and 51.62 Nβ for 1 and 2,slightly smaller than the expected saturation values.For further investigation of the dynamic behaviour,ac susceptibility measurements were undertaken under zero-dc field between 1～1500 Hz,they both show temperature dependence and have maximum values in the χM″ vs v plots above 1.8 K,indicating the presence of slow relaxation of the magnetization.After linear fitting the first four points of ln（τ/s） vs 1/T plot,we get energy barrier Ueff=9.83（9） K,pre-exponential factor τ0=1.63（2）×10-5 s for 1,and Ueff=12.05（2） K,τ0=6.75（8）×10-7 s for 2 respectively.The bridging mode of azido in complex 1 is novel and complex 2 holds the record for highest nuclearity among the reported pure lanthanide single

关 键 词：单分子磁体 镝 弛豫 簇合物 叠氮 

分 类 号：O611.3[理学—无机化学]