双稳态磁性配合物的设计合成和性能调控
发布时间：2018-07-17 04:15
【摘要】：随着科技的发展,从分子水平上研究具有特殊磁性功能的材料已经成为材料领域的研究热点。具有双稳态的磁性材料是实现分子集合体作为新的光/热开关以及信息存储元件的理想分子体系,成为分子基磁性材料研究领域的一个热点。目前,研究较为广泛的磁性双稳态材料主要包括在低温区具有缓慢磁弛豫的分子纳米磁体(尤其是稀土单分子磁体)和在室温附近具有自旋转换行为的自旋交叉配合物。基于以上背景和研究思路,本论文旨在设计合成具有特殊结构和性能的镧系稀土单分子磁体和自旋交叉配合物,并深入研究了它们的磁构关系及性能调控。研究成果如下:一、基于硫代杯[4]芳烃的五核稀土簇合物中的慢弛豫磁行为基于硫代杯[4]芳烃合成了六个五核簇状配合物[Ln_5(μ_4-OH)(μ_3-OH)_4(L_1)(acac)_6](H_4L_1 = P-tert-butylthiacalix[4]arene;acac =acetylacetonate;Ln = Dy(1),Ho(2),Er(3))和[Ln_5(μ_5-OH)(μ_3-OH)_4(L_1)(L_2)_2(acac)_2(CH_3OH)_2](H_3L_2 = 5,11,17,23-tetrakis(1,1-dimethylethyl)-25,26,27-trihydroxy-28-methoxy thiacalix[4]arene;Ln = Dy(4),Ho(5),Er(6))。每个配合物中的五个金属中心通过配体上的氧原子形成四角锥构型,不同之处是,在配合物1-3中,底面的四个LnⅢ离子通过一个μ4-OH桥联,而在4-6中,四边形底面的氧原子则是采取μ5-的方式连接着五个LnⅢ离子。磁性测试表明,配合物1-6中的金属离子之间存在弱的反铁磁作用,其中,两个含DyⅢ配合物的虚部交流磁化率具有明显的温度依赖行为。二、基于硫代杯[4]芳烃的Ni~(Ⅱ)-Ln~(Ⅲ)异双核配合物中的慢弛豫磁行为利用硫代杯[4]芳烃配体(H_2L_3 = 5,11,17,23-tetrakis(1,1-dimethylethyl)-25,27-dihydroxy-26,28-dimethoxy thiacalix[4]arene)和三齿席夫碱配体(H_3L_4 =1,1,1-tris[(salicylideneamino)methyl]ethane),采用分步合成的方法制备了一系列Ni~(Ⅱ)-Ln~(Ⅲ)异双核配合物[(NiLNiⅡ-Ln_4)Ln(L_3)((CH_3OH)]·acetone(Ln = Gd(7),Tb(8),Dy(9))。配合物7-9是同构的,NiⅡ和LnⅢ通过席夫碱配体的两个酚羟基桥联。NiⅡ离子处于{NiN3O3}的配位环境,六个配位原子全部来自配体L4;LnⅢ离子采取七配位{LnO7},被一个杯芳烃配体的四个氧原子紧紧包裹着。静态磁学性质表明这三个配合物中,NiⅡ与LnⅢ之间都存在铁磁交换作用,拟合得到的耦合常数JNi-Gd = 0.80 cm-1。动态磁学性质显示,配合物9具有场诱导的单分子磁体行为。我们又利用抗磁性的YⅢ对配合物9进行掺杂,得到的掺杂样品9'在零场下即表现出单分子磁体慢弛豫过程。三、溶剂得失调控的双核酞菁类LnⅢ配合物基于大环酞菁配体合成了三例双核稀土配合物[Ln_2(thd)_4Pc]·2C_6H_6(Hthd =2,2,6,6-tetramethylheptanedione;Pc = phthalocyanine;Ln = Sm(10),Tb(11),Dy(12))。当10-12中游离的苯分子丢失之后,可以得到配合物[Ln_2(thd)_4Pc](Ln= Sm(10'),Tb(11'),Dy(12')),溶剂诱导的结构转化是可逆的。实验结果显示,溶剂的丢失对配合物的结构和磁性质都产生了很大的影响。配合物12中只含有一种晶体学独立的金属中心,它表现出单弛豫过程,有效能垒为55.7 K。失去溶剂得到的12,含有两种金属中心,表现出双弛豫过程,能垒分别为63.3 K和109.6 K。最重要的是,配合物的动态磁行为可以通过溶剂苯分子的吸附和脱附可逆地调控。四、溶剂交换调控的双核酞菁类ErⅢ配合物我们利用Li_2Pc与[Er(thd)_3]·2H20制备了一例双核ErⅢ配合物[Er_2(thd)_4Pc]·2C_6H_6(13),该配合物在空气中稳定。将其浸泡在二氯甲烷溶剂中,晶格中游离的苯分子可以完全被二氯甲烷置换,得到新的配合物[Er_2(thd)_4Pc]·2CH_2Cl_2(14)。磁性测试表明,配合物13和14中存在不同的耦合作用。动态磁学性质分析结果显示,13在600 Oe的外磁场下依然表现出快弛豫过程,估算的能垒Ea只有2.6 cm-1,而14则具有场诱导的单分子磁体慢弛豫行为,有效能垒为34.3 cm-1。从头计算的结果表明13和14截然不同的磁行为与分子内ErⅢ离子之间不同的耦合作用有关,耦合作用的不同从根本上可归因于晶体结构的微小变化。对配合物13-re和14-re结构和磁性的进一步测试表明,配合物的单分子磁体性质可以通过溶剂交换可逆地调控。五、桥联配体调控的双核酞菁类DyⅢ配合物我们将配合物12'作为原料,与不同取代的水杨醛配体进一步反应,合成了两例结构新颖的双核 DyⅢ配合物[Dy2(Pc)2(MeO-L5)2(H2O)]·2THF(15,MeO-HL5=3-Methoxysalicylaldehyde)和[Dy2(Pc)2(EtO-L5)2(H2O)]·2THF(16,EtO-HL5 =3-ethoxy-2-hydroxybenzaldehyde)。配合物15和16是结构相似的混合型三层夹心型结构,上层和下层都是酞菁配体,中间层是两个不同配位方式的RL5配体,两个晶体学独立的金属中心Dy1和Dy2通过两个RL5的酚羟基相连,每个DyⅢ离子都处于{DyN4O4}的配位环境。静态磁学性质表明这两个配合物中,Dy1和Dy2之间存在不同强度的磁相互作用。动态磁学性质的分析结果显示,配合物15具有零场下的单分子磁体双弛豫行为,而16在零场下却表现出量子隧穿效应导致的快弛豫行为。从头计算的结果表明,15和16截然不同的磁行为与分子内DyⅢ离子之间不同的耦合作用有关,耦合作用的不同从根本可归因于桥联配体中不同尺寸的取代基对晶体结构造成的变化。六、溶剂响应的Fe~(Ⅱ)配合物及自旋态与荧光的耦合作用我 们 选 用[FeL_6(MeOH)_2](H_2L_6 = {diethyl(E,E)-2,2'-[1,2-phenylbis(iminomethylidyne)]bis[3-oxobutanoate]-(2-)-N,N'O3,O3'})作为反应前驱体,与荧光配体 L7(1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)-ethene)自组装,得到了配合物17·1.5CH2Cl2。17·1.5CH2Cl2具有四重穿插的二维网状结构,溶剂分子处于穿插之后的小空腔内,并通过多种非经典氢键作用与框架相连。对17和17·1.5CH2Cl2的变温磁化率测试表明,溶剂分子对配合物的自旋交叉行为具有显著影响。17的转变温度为205 K,而17·1.5CH2Cl2则表现出热滞回现象,滞回温度达到24 K。当溶剂为甲醇时,得到甲醇溶剂化的配合物17·3CH3OH,该配合物不仅表现出磁滞回现象,热滞回温度达到29 K,而且自旋转变程度也大大增加。此外,17的自旋转变温度与它的荧光强度发生不寻常倒转的温度吻合。我们不仅通过溶剂交换的方法在二维聚合物体系中实现了自旋交叉行为的调控(热滞回行为的开和关),而且成功地将荧光基团引入到自旋交叉体系中,并且两种性质之间存在协同效应。
[Abstract]:With the development of science and technology, the study of materials with special magnetic functions at the molecular level has become a hot topic in the field of materials. Bistable magnetic materials are an ideal molecular system to realize molecular aggregation as a new optical / thermal switch and information storage element, and become a hot spot in the field of molecular based magnetic materials. At present, a wide range of magnetic bistable materials mainly include slow magnetic relaxor molecular nanomaterials (especially rare earth monomolecular magnets) and spin cross complexes with spin conversion behavior near room temperature in low temperature zones. Based on the above background and research ideas, the purpose of this paper is to design and synthesize special structures and properties. The lanthanide lanthanide monomolecular magnets and spin cross complexes have been studied, and their magnetic relations and properties are studied. The results are as follows: 1. The slow relaxation magnetic behavior of five nuclear rare earth clusters based on thiosulfate [4] aromatics is based on the synthesis of six five nuclear cluster complexes, [Ln_5 (mu _3-OH) _4 (L_1), based on thiosulfate [4] aromatics (L_1). (ACAC) _6] (H_4L_1 = P-tert-butylthiacalix[4]arene; ACAC =acetylacetonate; Ln = Dy (1), Ho (2), Er (3)) and [Ln_5 (micron). The metal center forms the four pyramid configuration through the oxygen atom on the ligand. The difference is that in the complex 1-3, the four Ln III ions at the bottom are bridged by a single 4-OH, and in 4-6, the oxygen atoms at the bottom of the quadrangle are connected to five Ln III ions by the way of 5-. The magnetic test shows that the metal ions in the complex 1-6 are between the metal ions. There is a weak antiferromagnetic effect, in which the imaginary ac susceptibility of two Dy III complexes has obvious temperature dependence. Two, the slow relaxation magnetic behavior in the Ni~ (II) -Ln~ (III) heteronuclear complexes based on thiosulfate [4] arene uses the thiosulfate [4] arene ligand (H_2L_3 = 5,11,17,23-tetrakis (1,1-dimethylethyl) -25,27-dihydrox) Y-26,28-dimethoxy thiacalix[4]arene) and three tooth Schiff base ligand (H_3L_4 =1,1,1-tris[(salicylideneamino) methyl]ethane), a series of Ni~ (II) -Ln~ (II) -Ln~ (III) heteronuclear complexes [(NiLNi II -Ln_4) Ln (L_3)] (7), 8, 9) are prepared by step synthesis. The complex 7-9 is isomorphic The two hydroxyl bridged.Ni II ions of the Schiff base ligand are in the coordination environment of {NiN3O3}, and the six coordination atoms are all from the ligand L4; Ln III ions take seven coordination {LnO7} and are tightly wrapped by four oxygen atoms of a calixarene ligand. The static magnetic properties indicate that there are ferromagnetic fields between the three complexes, between Ni II and Ln III. The dynamic magnetic properties of the fitting coupling constant JNi-Gd = 0.80 cm-1. show that the complex 9 has the field induced single molecule magnet behavior. We also use the anti magnetic Y III to doping the complex 9, and the doped sample 9'shows the slow relaxation process of the single molecule magnets under zero field. Three, the double solvent gain and loss control Nuclear phthalocyanine Ln III complexes have synthesized three cases of [Ln_2 (Hthd =2,2,6,6-tetramethylheptanedione, Pc = phthalocyanine, Ln = Sm (10), Ln = Sm (10), Tb (11), 12) based on the macrocyclic phthalocyanine ligand. 2')), the structural transformation induced by solvent is reversible. The result of the experiment shows that the loss of the solvent has a great effect on the structure and magnetic properties of the complexes. The complex contains only one crystallographic independent metal center, which shows a single relaxation process, an effective barrier of 55.7 K. lost the solvent and two kinds of metal centers. The most important of the two relaxation processes, the energy barrier 63.3 K and the 109.6 K., is that the dynamic magnetic behavior of the complexes can be reversible by the adsorption and desorption of the solvent benzene molecules. Four, the binuclear phthalocyanine Er III complex controlled by the solvent exchange, we use Li_2Pc and [Er (THD) _3]. 2H20 to prepare a case of the dual nucleus Er III complex [Er_2 (THD). 4Pc]. 2C_6H_6 (13), the complex is stable in the air. It is soaked in the dichloromethane solvent. The free benzene molecules in the lattice can be completely replaced by dichloromethane, and the new complex [Er_2 (THD) _4Pc]. 2CH_2Cl_2 (14) is obtained. The magnetic test shows that there are different coupling effects in the complexes 13 and 14. The dynamic magnetic properties analysis results show that the complexes have different coupling effects. It is shown that 13 still shows a fast relaxation process under the external magnetic field of 600 Oe, the estimated energy barrier Ea is only 2.6 cm-1, and 14 has the field induced slow relaxation behavior of the single molecule magnet, and the effective energy barrier to 34.3 cm-1. ab initio shows that the 13 and 14 magnetic behaviors are related to the different coupling effects between the intramolecular Er III ions. The difference in use is fundamentally attributable to small changes in the crystal structure. Further tests on the structure and magnetism of the complexes 13-re and 14-re show that the properties of the single molecule magnets of the complexes can be reversible by solvent exchange. Five, the binuclear phthalocyanine Dy III complex regulated by the bridged ligand, we use the complex 12'as the raw material, and different Two Novel Binuclear Dy III complexes [Dy2 (Pc) 2 (MeO-L5) 2 (H2O)] 2THF (15, MeO-HL5=3-Methoxysalicylaldehyde) and [Dy2 (Pc) 2 (EtO-L5) 2 (H2O)] are synthesized by the substituted salicylaldehyde ligands. The complex 15 and 16 complexes are similar to the structure of three layer sandwich type junction. The upper and lower layers are phthalocyanine ligands, the middle layer is a RL5 ligand with two different coordination modes, two crystallographic independent metal centers Dy1 and Dy2 are connected by two RL5 phenolic hydroxyl groups, each Dy III ion is in the {DyN4O4} coordination environment. Static magnetic properties indicate that there are different strengths between Dy1 and Dy2 among the two complexes. Magnetic interaction. The analysis of the dynamic magnetic properties shows that the complex 15 has the double relaxation behavior of the single molecule magnets under zero field, while the 16 in the zero field shows the fast relaxation behavior caused by the quantum tunneling effect. The results of the ab initio show that the coupling effect between the 15 and 16 magnetic behavior and the intramolecular Dy III ions is different. The difference in coupling is fundamentally attributable to the changes in the crystal structure of the substituents of different sizes in the bridging ligands. Six, we choose [FeL_6 (MeOH) _2] (E, E) -2,2'-[1,2-phenylbis (iminomethylidyne)]bis[3-oxobutanoa by the coupling of the solvent response Fe~ (II) complex and the spin state with the fluorescence. Te]- (2-) -N, N'O3, O3'}), as a reaction precursor, is self assembled with the fluorescent ligand L7 (1,1,2,2-tetrakis (4- (pyridin-4-yl) phenyl) -ethene), and a two-dimensional mesh structure with four heavy interspersed ligand 17. Is obtained. The solvent molecules are in the small cavity after the insertion of the solvent, and through a variety of non classical hydrogen bonding interactions with the frame phase The variable temperature magnetic susceptibility test for 17 and 17 1.5CH2Cl2 shows that the solvent molecules have a significant effect on the spin cross behavior of the complex, and the transition temperature of.17 is 205 K, while 17. 1.5CH2Cl2 shows a thermal hysteresis, and the hysteresis temperature is 24 K.. When the solvent is methanol, the coordination compound of methanol is 17. 3CH3OH. The hysteresis of magnetic hysteresis is shown, the thermal hysteresis temperature reaches 29 K, and the spin transition degree is also greatly increased. In addition, the spin transition temperature of 17 is consistent with the unusual inversion temperature of its fluorescence intensity. We not only realize the regulation of the spin cross behavior in the two-dimensional polymer system by the method of solvent exchange (the thermal hysteresis behavior). The fluorescent group was successfully introduced into the spin crossover system, and synergistic effects between the two properties were achieved.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O641.4
[Abstract]:With the development of science and technology, the study of materials with special magnetic functions at the molecular level has become a hot topic in the field of materials. Bistable magnetic materials are an ideal molecular system to realize molecular aggregation as a new optical / thermal switch and information storage element, and become a hot spot in the field of molecular based magnetic materials. At present, a wide range of magnetic bistable materials mainly include slow magnetic relaxor molecular nanomaterials (especially rare earth monomolecular magnets) and spin cross complexes with spin conversion behavior near room temperature in low temperature zones. Based on the above background and research ideas, the purpose of this paper is to design and synthesize special structures and properties. The lanthanide lanthanide monomolecular magnets and spin cross complexes have been studied, and their magnetic relations and properties are studied. The results are as follows: 1. The slow relaxation magnetic behavior of five nuclear rare earth clusters based on thiosulfate [4] aromatics is based on the synthesis of six five nuclear cluster complexes, [Ln_5 (mu _3-OH) _4 (L_1), based on thiosulfate [4] aromatics (L_1). (ACAC) _6] (H_4L_1 = P-tert-butylthiacalix[4]arene; ACAC =acetylacetonate; Ln = Dy (1), Ho (2), Er (3)) and [Ln_5 (micron). The metal center forms the four pyramid configuration through the oxygen atom on the ligand. The difference is that in the complex 1-3, the four Ln III ions at the bottom are bridged by a single 4-OH, and in 4-6, the oxygen atoms at the bottom of the quadrangle are connected to five Ln III ions by the way of 5-. The magnetic test shows that the metal ions in the complex 1-6 are between the metal ions. There is a weak antiferromagnetic effect, in which the imaginary ac susceptibility of two Dy III complexes has obvious temperature dependence. Two, the slow relaxation magnetic behavior in the Ni~ (II) -Ln~ (III) heteronuclear complexes based on thiosulfate [4] arene uses the thiosulfate [4] arene ligand (H_2L_3 = 5,11,17,23-tetrakis (1,1-dimethylethyl) -25,27-dihydrox) Y-26,28-dimethoxy thiacalix[4]arene) and three tooth Schiff base ligand (H_3L_4 =1,1,1-tris[(salicylideneamino) methyl]ethane), a series of Ni~ (II) -Ln~ (II) -Ln~ (III) heteronuclear complexes [(NiLNi II -Ln_4) Ln (L_3)] (7), 8, 9) are prepared by step synthesis. The complex 7-9 is isomorphic The two hydroxyl bridged.Ni II ions of the Schiff base ligand are in the coordination environment of {NiN3O3}, and the six coordination atoms are all from the ligand L4; Ln III ions take seven coordination {LnO7} and are tightly wrapped by four oxygen atoms of a calixarene ligand. The static magnetic properties indicate that there are ferromagnetic fields between the three complexes, between Ni II and Ln III. The dynamic magnetic properties of the fitting coupling constant JNi-Gd = 0.80 cm-1. show that the complex 9 has the field induced single molecule magnet behavior. We also use the anti magnetic Y III to doping the complex 9, and the doped sample 9'shows the slow relaxation process of the single molecule magnets under zero field. Three, the double solvent gain and loss control Nuclear phthalocyanine Ln III complexes have synthesized three cases of [Ln_2 (Hthd =2,2,6,6-tetramethylheptanedione, Pc = phthalocyanine, Ln = Sm (10), Ln = Sm (10), Tb (11), 12) based on the macrocyclic phthalocyanine ligand. 2')), the structural transformation induced by solvent is reversible. The result of the experiment shows that the loss of the solvent has a great effect on the structure and magnetic properties of the complexes. The complex contains only one crystallographic independent metal center, which shows a single relaxation process, an effective barrier of 55.7 K. lost the solvent and two kinds of metal centers. The most important of the two relaxation processes, the energy barrier 63.3 K and the 109.6 K., is that the dynamic magnetic behavior of the complexes can be reversible by the adsorption and desorption of the solvent benzene molecules. Four, the binuclear phthalocyanine Er III complex controlled by the solvent exchange, we use Li_2Pc and [Er (THD) _3]. 2H20 to prepare a case of the dual nucleus Er III complex [Er_2 (THD). 4Pc]. 2C_6H_6 (13), the complex is stable in the air. It is soaked in the dichloromethane solvent. The free benzene molecules in the lattice can be completely replaced by dichloromethane, and the new complex [Er_2 (THD) _4Pc]. 2CH_2Cl_2 (14) is obtained. The magnetic test shows that there are different coupling effects in the complexes 13 and 14. The dynamic magnetic properties analysis results show that the complexes have different coupling effects. It is shown that 13 still shows a fast relaxation process under the external magnetic field of 600 Oe, the estimated energy barrier Ea is only 2.6 cm-1, and 14 has the field induced slow relaxation behavior of the single molecule magnet, and the effective energy barrier to 34.3 cm-1. ab initio shows that the 13 and 14 magnetic behaviors are related to the different coupling effects between the intramolecular Er III ions. The difference in use is fundamentally attributable to small changes in the crystal structure. Further tests on the structure and magnetism of the complexes 13-re and 14-re show that the properties of the single molecule magnets of the complexes can be reversible by solvent exchange. Five, the binuclear phthalocyanine Dy III complex regulated by the bridged ligand, we use the complex 12'as the raw material, and different Two Novel Binuclear Dy III complexes [Dy2 (Pc) 2 (MeO-L5) 2 (H2O)] 2THF (15, MeO-HL5=3-Methoxysalicylaldehyde) and [Dy2 (Pc) 2 (EtO-L5) 2 (H2O)] are synthesized by the substituted salicylaldehyde ligands. The complex 15 and 16 complexes are similar to the structure of three layer sandwich type junction. The upper and lower layers are phthalocyanine ligands, the middle layer is a RL5 ligand with two different coordination modes, two crystallographic independent metal centers Dy1 and Dy2 are connected by two RL5 phenolic hydroxyl groups, each Dy III ion is in the {DyN4O4} coordination environment. Static magnetic properties indicate that there are different strengths between Dy1 and Dy2 among the two complexes. Magnetic interaction. The analysis of the dynamic magnetic properties shows that the complex 15 has the double relaxation behavior of the single molecule magnets under zero field, while the 16 in the zero field shows the fast relaxation behavior caused by the quantum tunneling effect. The results of the ab initio show that the coupling effect between the 15 and 16 magnetic behavior and the intramolecular Dy III ions is different. The difference in coupling is fundamentally attributable to the changes in the crystal structure of the substituents of different sizes in the bridging ligands. Six, we choose [FeL_6 (MeOH) _2] (E, E) -2,2'-[1,2-phenylbis (iminomethylidyne)]bis[3-oxobutanoa by the coupling of the solvent response Fe~ (II) complex and the spin state with the fluorescence. Te]- (2-) -N, N'O3, O3'}), as a reaction precursor, is self assembled with the fluorescent ligand L7 (1,1,2,2-tetrakis (4- (pyridin-4-yl) phenyl) -ethene), and a two-dimensional mesh structure with four heavy interspersed ligand 17. Is obtained. The solvent molecules are in the small cavity after the insertion of the solvent, and through a variety of non classical hydrogen bonding interactions with the frame phase The variable temperature magnetic susceptibility test for 17 and 17 1.5CH2Cl2 shows that the solvent molecules have a significant effect on the spin cross behavior of the complex, and the transition temperature of.17 is 205 K, while 17. 1.5CH2Cl2 shows a thermal hysteresis, and the hysteresis temperature is 24 K.. When the solvent is methanol, the coordination compound of methanol is 17. 3CH3OH. The hysteresis of magnetic hysteresis is shown, the thermal hysteresis temperature reaches 29 K, and the spin transition degree is also greatly increased. In addition, the spin transition temperature of 17 is consistent with the unusual inversion temperature of its fluorescence intensity. We not only realize the regulation of the spin cross behavior in the two-dimensional polymer system by the method of solvent exchange (the thermal hysteresis behavior). The fluorescent group was successfully introduced into the spin crossover system, and synergistic effects between the two properties were achieved.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O641.4
【相似文献】
相关期刊论文 前10条
1 武芳卉,周峥嵘,王全瑞,丁宗彪,陶凤岗,夏 q，
本文编号：2128968
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2128968.html
教材专著
