【作者】 王璇；

【导师】 高恩庆；

【作者基本信息】 华东师范大学 ， 无机化学， 2013， 硕士

【摘要】 以吡啶羧酸盐作为羧酸配体与叠氮化物连用可以有效的得到由羧基叠氮混合桥联的配合物,可以获得桥联方式复杂多样、磁行为较为新颖的配合物。以此延伸的咪唑羧酸盐在催化领域已得到广泛的研究,例如作为功能化离子液体用于催化反应或作为氮杂环卡宾(NHC)的前驱体等。近几年开始利用咪唑羧酸盐配体构筑配位聚合物或金属有机骨架。本论文选用叠氮离子为桥联配体,引入咪唑酸盐配体为羧酸配体,以此得到了多种金属的配合物,测定了结构并对其相关性质进行了表征。本论文主要内容如下：1.以1-甲基-3-羧基咪唑(L1)为羧酸配体构筑的配合物我们利用内盐型单羧基配体L1得到了同晶的Mn(Ⅱ)、Co(Ⅱ)配合物[M(LⅠ)(N3)4]n (M=Mn(1)、Co(2)),其中相邻的金属离子通过两个EO叠氮桥一个羧基桥连接成一维结构。磁性研究表明配合物1表现为反铁磁耦合,而配合物2铁磁耦合。2.以1,3-双羧甲基咪唑(HL2)为羧酸配体构筑的配合物配体HL2构筑配合物时脱去羧基上的质子,作为阴离子配体。[1]表现为反铁磁耦合的配合物[Mn()(N3)]n(3)中相邻的Mn(Ⅱ)间通过双EO叠氮单羧基三重混桥连接成一维结构,临近的一维链通过L2连接成二维层。[2]配合物{[Co5(L2)2(N3)6(CH3CH2O)2(H2O)4]·(H2O)2}n(4)的不对称单元中含有3种独立的Co(Ⅱ),其中一种通过双羧基单叠氮桥与由通过EO叠氮桥和烷基氧桥构筑的共面缺角立方烷结构交替连接成一维结构,后通过L2延伸为二维层。[3]二维配合物[Mn(L2)(N3)]n(5)中相邻的Mn(Ⅱ)通过双羧基桥单EE叠氮桥相连。[4]表现为铁磁耦合的配合物[Cu3(L2)(N3)5]n(6)中的Cu(Ⅱ)通过羧基桥和单EO叠氮桥连成一维链,链与链之间通过双EO及单EE叠氮桥相连。最后经由配体L2连成三维骨架。[5]配合物[Cu5(N3)6(L2)4]n(7)中由双羧基单EO叠氮桥桥联的三核单元和由双EO叠氮桥联的二核单元交替连接成一维结构。该一维链通过配体L2连成三维框架结构。[6]配合物[Cu()2]n(8)中L2为单齿配体,金属离子通过配体连成一维结构。3.以1,3-双(1-羧乙基)咪唑(HL3)为羧酸配体构筑的配合物配体HL3中含有手性碳,故在实际的合成过程中用到了三种配体,分别为S, S-HL3、R,S-HL3和R,R-HL3。[1]表现为反铁磁耦合的二维配合物9、10为分别利S,S-HL3、R,R-HL2合成的同晶结构。配合物[Mn(S,S-L3)(N3)]·0.5CH3OH (9)中的Mn(II)通过三重混合的羧基叠氮桥联。[2]-L3)2(N3)4(H2O)2](12)利用具有内消旋特性的R,S-HL3合成。该配合物通过线性的三核单元结构连成三维骨架。配合物12具有自旋倾斜行为。[3]表现为铁磁耦合的[Cu8(R,S-L3)2(N3)14]n(13)也是利用R,S-HL3制得。该配合物由羧基叠氮桥联的六核单元与双EO叠氮桥联的二核单元交替连接形成一维链,后经由单EE叠氮桥延展为二维结构。最后通过配体L3连成三维骨架。更多还原

【Abstract】 The use of pyridinium-based carboxylates as co-ligands with azide is an easy and fruitful synthetic approach to such mixed bridges, leading to magnetic compounds with various bridging networks and interesting properties, such as ferromagnetism, spin canting, single-chain-magnet (SCM) behavior, and solvomagnetic effects. The approach benefits from the zwitterionic nature of the carboxylate ligands, which helps to balance the competition between carboxylate and azide in binding metal cations. Imidazolium-based carboxylic acids have been studied as functionalized ionic liquids for catalytic reactions and as precursors for functionalized N-heterocyclic carbenes (NHCs), and only in the last several years, they have been used as bridging ligands to construct coordination polymers or metal-organic frameworks. The combination of the chiral zwitterions and azide as co-ligands for paramagnetic metal ions should be a new and facile approach to chiral magnetic systems.In this treatise, the azide ion was chosen as the bridging ligand, and the imidazolium was introduced to be the auxiliary ligand to construct and control the construction of framework。Six kinds of imidazium ligands were synthesized according to the literature, the neutral ligand, the mono-anionic achiral ligand, the mono-anionic enantiomeric and mesomeric ligands. With this series of ligands, which are different in carboxylate number, in charge, and/or in chirality, we are able to observe various coordination networks and different magnetic properties. Different kinds of transition metal coordination polymers have been synthesized and characterized. The main content of this treatise are as follows:1. Coordination polymers constructed by1-methyl-3-(carboxylatomethyI)imida-zolium(L1)The auxiliary ligand L1is neutral. The coordination [Mn(L1)(N3)2]n(1) was synthesized with it. The unique Mn(Ⅱ) ion lies in a trans-octahedral coordination environment. Neighboring Mn(Ⅱ) ions are connected by two azide bridges in the end-on (EO) mode and a carboxylate bridge in the μ-O,O’mode to give an infinite chain along b direction. We did not get the crystal of cobalt, however compounad1and2are isomorphous, which have been confirmed by XRD. In compound1, neighboring Mn(Ⅱ) centers exists antiferromagnetic coupling and ferromagnetic coupling for compound2.2. Coordination polymers constructed by1,3-bis(carboxylatomethyl)imidazo-lium (HL2)Through the auxiliary ligand HL2, six coordination compound with Mn(Ⅱ)、 Co(Ⅱ)、Cu(Ⅱ) were got。The ligand lost the proton of the carboxyl when connect the metal ions, and worked as an anion co-ligand.[1] Compound [Mn(L2)(N3)]n (3) consists of2D coordination layers based on Mn(Ⅱ) chains with mixed azide and carboxylate bridges. In compound3, neighboring Mn(Ⅱ) centers exists antiferromagnetic coupling.[2] The asymmetric unit of compound {[Co5(L2)2(N3)6(CH3CH2O)2(H2O)4]·(H2-0)2}n(4) contains three Co(Ⅱ) cations, and two of them were combined by two μ1，1-N3and one μ,1,1-OH, then this motif was connected with two Co3(Ⅱ) cation through μ1,1,1-OH to construct a tetra-nuclear units. The terminal metal ions were bridged to Col by bis(COO)(N3),and these two motifs alternately connected to a dimensional chain, then with the help of co-ligand we got a2D layer which is parallel to ac direction.[3] Compound [Mn(L2)(N3)]n(5) contains consists of2D coordination layers based on Mn(Ⅱ) chains with mixed μ1,3-N3and carboxylate bridges.[4] Cul and Cu3, Cu2and Cu4were combined with each other through μ1,1-N3anion and Cul and were bridged to each other through twoμ1,1-N3anion in addition in compound [Cu3(L2)(N3)5]n(6). Cu1and Cu3, Cu2and Cu4were combined with each other through μ1,1-N3anion and Cul and were bridged to each other through twoμ1,1-N3anion in addition in compound [Cu3(L2)(N3)5]n(6). What’s more the four kinds of copper ions alternately connected to a two dimensional layer and further constructed to metal-organic framework with the co-ligand. In compound6, neighboring Cu(Ⅱ) centers exists ferromagnetic coupling.[5] Cu3and Cu3were combined with each other through two μ1,1-N3anion and connected with the other copper cationins alternately to one dimensional chain in compound [Cus(N3)6(L)4]n (7). There two types of coordination mode for the co-ligand. The oxygen atoms in some of the ligands coordinated two metals while the other ones only coordinated one metal. With the help of co-ligand we got a3D coordination compound.[6] The structure of compound [Cu(L2)2]n (8) is simple. Only O1and O3were coordinated, and the adjacent metal ions were linked to one dimensional structure.3. Coordination polymers constructed by the mono-anionic enantiomeric and mesomeric ligands (S,S)-,(R,R)-, and (R,S)-1,3-bis(1-carboxylatoethyl)imidazoli-um [S,S-L3,R,R-L3and R,S-L3][1] Compound9was synthesized with HS,S-L3, and compound10was synthesized with GRm,R-L3co-ligand. The two compounds are isomorphous. Compound9crystallizes in the chiral space group C2. It also contains2D coordination layers based on Mn(II) chains with mixed azide and carboxylate bridges. The asymmetric unit contains an Mn(II) ion, an azide anion, an S,S-L3ligand and half a methanol molecule. The anionic Mn(μ-N3)(μ-COO)2chains in9are interlinked by the cationic imidazolium-based spacers of the S,S-L3ligands to produce2D metal-organic layers parallel to the ab plane. In compound9, neighboring Mn(II) centers exists antiferromagnetic coupling. In addition, we also obtained compound11with S,S-L4.[2] The use of mesomeric R.S-L3instead of R,R-L (or S,S-L3) in the same synthetic procedure leads to a quite different structure. Compound [Mn3(R,S-L3)2(N3)4(H2O)2](12) crystallizes in the centrosymmetric space group P21/c, and exhibits a3D framework based on linear anionic trinuclear units. The asymmetric unit contains half of the formula. The Mn1atom resides at a general position and assumes a distorted mer-octahedral [MnN3O3] coordination geometry. The Mn2atom is located at an inversion center and coordinated in the trans-octahedral geometry. Through a pair of (μ-EO-N3)(μ-COO)2triple bridges, each Mn2is linked to two Mnl atoms to form a centrosymmetric linear trinuclear motif of formula [Mn3(N3)2(COO)4]. The carboxylate bridges adopt either the quasi-planar syn-syn mode or the out-of-plane syn-skew mode. Each unit is connected with four identical motifs to generate a2D layer parallel to the be plane. The layers are pillared into a3D framework by the backbones of the R,S-L3ligands. Compound12shows canted antiferromagnetism and behaves as a weak ferromagnet.[3] Compound [Cu8(R,S-L3)2(N3)14]n (13) was also obtained by R,S-L3. It contains four independent Cu(II) cations. Cu1, Cu2and Cu3connected into hexa-nuclear units. Cu4and Cu4were linked into binary units through bis(μ1,1-N3). The two motifs were alternately connected into a chain and then the chain was further linked to two dimensional layer with single μ1,3-N3bridge.3D framework was constructed through the ligand. Compound13shows ferromagnetism.[4] Compound [Cu6(DMF)2(N3)8(Cl)4]n (14) was achieved by introducing S,S-L3. Two N,N’-dimethylformamide and two chloride acted as coordinate ligands. It is a zero dimensional structure.更多还原