基于2-羟甲基吡啶配体的分子基磁性材料的合成、结构和磁性研究
发布时间：2018-07-27 12:43
【摘要】：分子基磁性材料具有结构可调、磁损耗小、溶解性好、质地轻等特点,在高密度信息储存器、分子开关等领域具有巨大的应用前景。目前已经合成了许多结构各异的分子基磁性材料,表现出多种不同的磁性:反铁磁性、亚铁磁性、铁磁性、自旋翻转、自旋玻璃、自旋倾斜、自旋交叉等。但是如何通过有效的制备方法获得具有预期结构的晶体,并在分子层面上调节其磁性,从而得到具有目标磁性的分子基磁性材料仍然是一个挑战。本论文中,我们选择2-羟甲基吡啶(Hhmp)和甲酸为配体合成了八个化合物,并对其结构-磁性的相互关系进行了系统地研究:(1)利用Hhmp、甲酸和来自空气中的CO_2形成的碳酸作为桥联配体成功合成了两个九核钴配合物[Co9(hmp)6(CHOO)6(CO3)2(H2O)6](Cl O4)2·11H2O(1)和[Co9(hmp)6(CHOO)7(CO3)2(H2O)5]ClO4·CH3CN·12H2O(2)。用一个甲酸配体替换化合物1中的一个水分子配体,使化合物1中的{Co9}2+簇转变为化合物2中的{Co9}+簇,导致化合物1和2的晶体堆积模式不同。核簇电荷的改变使分子间相互作用发生变化,表现为:化合物1显示反铁磁行为,而化合物2表现自旋玻璃行为。(2)以Hhmp为配体,通过溶剂诱导合成了三个立方烷型铜配合物:[Cu4(hmp)4(CHOO)2(H2O)2](ClO4)2·2H2O(3),[Cu8(hmp)8(CHOO)4(CH3CN)2(H2O)4](Cl O4)4·2CH3CN(4),{[Cu2(hmp)2(CHOO)(H2O)]ClO4·H2O}n(5)。通过改变溶剂比例,可将单立方烷四核铜簇3成功转变为具有双立方烷结构的八核铜簇4,通过甲酸桥联配体的进一步延伸得到多立方烷链5。单立方烷化合物3和双立方烷化合物4均具有反铁磁相互作用,多立方烷化合物5表现出铁磁相互作用。(3)通过改变中心金属和溶剂比例,成功合成了三个以Hhmp和甲酸为配体的立方烷型配合物:[Ni4(hmp)4(CHOO)2(H2O)4](ClO4)2(6),[Ni4(hmp)4(CHOO)4(H2O)2]·5.5H2O(7),[Co4(hmp)6(H2O)2(CH3CN)2](ClO4)4·4CH3CN(8)。四核镍化合物6和7具有相似的立方烷结构,不同的金属配位环境,均表现反铁磁相互作用。四核钴化合物8具有缺立方烷结构,表现长程有序行为。
[Abstract]:Molecular based magnetic materials have the advantages of adjustable structure, low magnetic loss, good solubility and light texture, so they have great application prospects in high density information storage, molecular switch and other fields. At present, many molecular based magnetic materials with different structures have been synthesized, showing various magnetic properties, such as antiferromagnetism, ferromagnetism, spin flip, spin glass, spin tilt, spin cross and so on. However, it is still a challenge to obtain the desired structure of crystals by effective preparation and adjust their magnetic properties at the molecular level to obtain the molecular based magnetic materials with target magnetic properties. In this thesis, we selected 2-hydroxymethylpyridine (Hhmp) and formic acid as ligands to synthesize eight compounds. The relationship between structure and magnetism was systematically studied. (1) two Co9 (hmp) 6 (CHOO) 6 (CO3) 2 (H 2O) 6 (CLO 4) 2 11H2O (1) and [Co9 (hmp) 6 (CHOO) 7 (CO3) 2 (H 2O) 5] ClO4 CH3CN 12H2O (2) complexes were successfully synthesized by using HHMP, formic acid and carbonic acid formed from air as bridging ligands in the presence of [Co9 (hmp) 6 (CHOO) 6 (CO3) 2 (H 2O) 6] (CLO 4) 2 11H2O (1) and [Co9 (hmp) 6 (CHOO) 7 (CO3) 2 (H 2O) 5] ClO4 CH3CN 12H2O (2). The {Co9} 2 cluster in compound 1 is transformed into {Co9} cluster in compound 2 by replacing an aqueous ligand in compound 1 with a formic acid ligand. The crystal stacking modes of compound 1 and 2 are different. 鏍哥皣鐢佃嵎鐨勬敼鍙樹娇鍒嗗瓙闂寸浉浜掍綔鐢ㄥ彂鐢熷彉鍖，
本文编号：2147867
[Abstract]:Molecular based magnetic materials have the advantages of adjustable structure, low magnetic loss, good solubility and light texture, so they have great application prospects in high density information storage, molecular switch and other fields. At present, many molecular based magnetic materials with different structures have been synthesized, showing various magnetic properties, such as antiferromagnetism, ferromagnetism, spin flip, spin glass, spin tilt, spin cross and so on. However, it is still a challenge to obtain the desired structure of crystals by effective preparation and adjust their magnetic properties at the molecular level to obtain the molecular based magnetic materials with target magnetic properties. In this thesis, we selected 2-hydroxymethylpyridine (Hhmp) and formic acid as ligands to synthesize eight compounds. The relationship between structure and magnetism was systematically studied. (1) two Co9 (hmp) 6 (CHOO) 6 (CO3) 2 (H 2O) 6 (CLO 4) 2 11H2O (1) and [Co9 (hmp) 6 (CHOO) 7 (CO3) 2 (H 2O) 5] ClO4 CH3CN 12H2O (2) complexes were successfully synthesized by using HHMP, formic acid and carbonic acid formed from air as bridging ligands in the presence of [Co9 (hmp) 6 (CHOO) 6 (CO3) 2 (H 2O) 6] (CLO 4) 2 11H2O (1) and [Co9 (hmp) 6 (CHOO) 7 (CO3) 2 (H 2O) 5] ClO4 CH3CN 12H2O (2). The {Co9} 2 cluster in compound 1 is transformed into {Co9} cluster in compound 2 by replacing an aqueous ligand in compound 1 with a formic acid ligand. The crystal stacking modes of compound 1 and 2 are different. 鏍哥皣鐢佃嵎鐨勬敼鍙樹娇鍒嗗瓙闂寸浉浜掍綔鐢ㄥ彂鐢熷彉鍖，
本文编号：2147867
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