【作者】 靳路通；

【导师】 王新强； 任诠；

【作者基本信息】 山东大学 ， 材料学， 2013， 硕士

【摘要】 有机金属配位化合物由于其结构的多变性和独特性,在不对称催化、多孔气体吸附、光学、电学、磁学等方面具有良好的应用前景和重要的应用价值,是当今配位化学、材料学和生命科学研究的热点之一。而在诸多有机配体之中,1,3-二硫杂环戊烯-2-硫酮-4,5-二巯基(DMIT)具有良好的π共轭结构,从而有利于电子在分子间的转移,传导和交换过程。自从该配体于1975年被首次合成以来,相关金属DMIT配合物的物理性质报导已经超过300篇,而且涉及的领域也十分广泛,如超导、半导体、有机分子磁体、非线性光学材料等。本论文以合成新型配合物,发现新物理性质,探讨性能与固态结构关系为目的,利用DMIT配体与过渡金属离子以及各种阳离子组装成一系列配合物。对得到的配合物进行了光谱表征,基本物化性能测试,结构解析,并对其非线性光学和磁学性质进行了研究。研究内容概要如下：1.适用于全光开关的配合物设计合成以及三阶非线性光学性质研究适用于全光开关器件的材料要求具有大的三阶非线性折射系数、快的响应速度、低的吸收、低的光传输损耗以及高的物理化学稳定性和热稳定性,易于加工并可形成波导全光原型器件。本论文致力于探索和研究具有高三阶非线性光学效应和超快响应速度的三阶非线性光学材料,针对全光开关对材料三阶非线性光学性质的要求,从材料分子结构的研究出发,探讨了影响材料三阶非线性光学性质的各项因素。通过改变配合物外界阳离子和中心金属离子,利用DMIT的高度离域的π电子体系,成功合成了一系列基于Hg(dmit)2、Mn(dmit)2和Cd(dmit)2的配合物,并对这些配合物进行了基本物化表征和三阶非线性光学性质的研究。本论文选用激光z扫描方法来研究DMIT配合物的非线性光学性质。实验中采用532nm,20ps脉冲激光照射样品。在研究中发现了一种在蓝绿光通信领域有潜在应用的Cd-DMIT配合物(TBA)2[Cd(dmit)2](TBA=四丁基铵)。利用显微结晶研究了该化合物在不同溶剂中的结晶形貌,并通过溶剂蒸发法自发成核结晶获得了小体块单晶。闭孔Z扫描测试归一化曲线显示出典型的中心对称图样,这表明该材料对于532nm,20ps脉冲激光无非线性吸收。经计算,其三阶非线性折射率和二阶分子超极化率分别为9.409×10-18m2/W和2.774×10-30esu,都大于同类化合物1个数量级以上。结果表明,(TBA)2[Cd(dmit)2]具有三阶非线性折射率大、非线性吸收系数小及响应速度快的特点,在全光开关器件的应用中具有潜在的价值。2. DMIT配合物的磁性研究采用大分子阳离子烷基三苯基膦设计合成了两种Ni-DMIT配合物：(乙基三苯基膦)[Ni(dmit)2](?)(?)(丙基三苯基膦)Ni(dmit)2]。并对其进行了基本物化表征和X射线单晶衍射的测试。结构分析表明配合物中可能有着较强的磁相互作用。为了研究物质的磁性,本论文做了变温磁化率和电子顺磁共振测试。两种配合物都表现出反常规的磁化率-温度曲线,表明该类化合物在磁有序结构,但这种曲线又并非典型原子磁体的磁性曲线,需要采用分子磁学方法来进行解释。根据化合物的结构,确立自旋模型,对两种物质的磁性进行了分析。结果在(丙基三苯基膦)[Ni(dmit)2]中发现了磁四聚体的存在,这是在DMIT配合物中较为少见的一类磁有序结构,这也是采用常规合成方法首次报道的磁四聚体。综上所述,本论文通过分子设计和晶体工程方面制备了一系列DMIT配合物材料,并选择性地对部分材料进行子三阶非线性光学学性质和磁性研究研制出了种在全光开关领域具有潜在应用价价的材料和种反铁磁四聚体材料。更多还原

【Abstract】 Organometallics are a series of compounds that possess good application value and prospects in asymmetric catalysis, porous gas adsorption, optics, electronics and magnetism because of their structural diversities and uniqueness. It is one of the most popular topics in current coordination chemistry, material science and bioscience. Among many organic ligands,1,3-dithiol-2-thioxo-4,5-dithiolate (DMIT) possesses a good π-conjugated structure, which greatly facilitates the charge-transferring, electron-conducting and spin-exchanging. Since it is first synthesized in1975, more than300papers have been reported concerning the physical properties of DMIT complexes. Meanwhile, the research fields these reports involve are very extensive, including superconductor, semiconductor, organic molecule magnets and nonlinear optical (NLO) materials. The dissertation aims at synthesizing novel coordination compounds, discovering new physical properties and investigating structure-property relationships, and makes use of DMIT ligand, transition metals and various counter-cations to assembly a series of complexes. The obtained complexes are characterized by spectroscopic analyses, elementary physicochemical tests and X-ray crystallographic studies, with their NLO and magnetic properties particularly and deeply investigated. The main research contents are summarized as follows:1. Design and synthesis of complexes for all-optical switching applications and investigations of third-order NLO propertiesFor realization of all-optical switching devices, the following material requirements have to be met:large third order nonlinear refractive coefficient, fast response time, low absorption and optical transmission loss, high physicochemical stability and thermal stability and processability to form original all-optical switching waveguide device. This dissertation is devoted to the exploration and investigation of third-order NLO materials with high third-order NLO effects and ultra-fast response time. According to material requirements of all-optical switchings, multiple factors influencing the third-order NLO properties of materials were probed and discussed from the molecular structures of the material. A series of complexes based on Hg(dmit)2, Mn(dmit)2and Cd(dmit)2were successfully synthesized by changing counter-cations and central metal ions and using highly delocalized π-electron system. Elementary physicochemical characterizations and third-order NLO studies are performed on these complexes.Z-scan technique was selected for the NLO property studies using a532nm,20ps laser pulse irradiation. A complex of (TBA)2[Cd(dmit)2](TBA=tetrabutylammonium) which could be of potential interests in all-optical switching applications at blue-green light band has been discovered. Micro-crystallization morphology was used to study crystallization tendency in different solvents. A small bulk single-crystal was obtained through solvent evaporation and spontaneous nucleation. Closed-aperture shows a typical central-symmetric profile, which indicates no nonlinear absorption. The magnitude of third-order nonlinear refraction index n2and the second order molecular hyperpolarizability γ are9.409×10-18m2/W and2.774×10-30esu, respectively, both of which are much larger than analogous compounds. The high nonlinear refraction coefficient and extremely low nonlinear absorption coefficient, combined with the fast response time, suggests that this material could be a potential candidate for application as all-optical switching devices.2. Magnetic studies of DMIT complexesTwo Ni-DMIT complexes:(ethyl-triphenylphosphate)[Ni(dmit)2] and (propyl-triphenylphosphate)[Ni(dmit)2] were designed and synthesized using large cations alkyl-triphenylphosphates. Elementary physicochemical characterizations and single crystal X-ray diffractions have been performed on these two salts. Structural analyses indicate strong magnetic interactions within polymers. To investigate the magnetic properties, variable-temperature magnetic measurements and electron paramagnetic resonance were carried out. Both salts exhibit unusual susceptibility-temperature curves, which suggest magnetic-orders in the compounds. Since these curves have no typical shapes of atom-based magnets, molecular magnetism strategies are needed to explain the phenomenon. Based on the crystal structures, spin models were established and the magnetic properties were analyzed. It turns out that a magnetic tetramer is observed in (propyl-triphenylphosphate)[Ni(dmit)2], which is quite rarely seen in DMIT complexes. This is also the first example of Ni(dmit)2tetramers obtained by regular metathetical reactions.In summary, in this dissertation a series of DMIT materials have been prepared through molecular designing and crystal engineering, and their third-order NLO and magnetic properties have also been selectively studied. One compound as a potential candidate in all-optical switching and an anti-ferromagnetic tetramer based on DMIT have been discovered.更多还原