节点文献
柔性联吡啶胺金属有机晶态网络的设计合成与荧光性能
Well-designed Syntheses and Luminescent Properties of Metal-organic Crystal Networks Based on Flexible Bis(pyridyl)Amine
【作者】 张竹艳;
【作者基本信息】 黑龙江大学 , 无机化学, 2013, 博士
【摘要】 近十几年来,联吡啶类金属有机晶态网络化合物因其丰富的拓扑结构及其在新功能材料如光致发光、分子磁体、气体存储、选择性催化和手性拆分等方面显示出的诱人应用前景而备受关注,并已取得了很多令人瞩目的科研成果。但迄今对非对称柔性联吡啶类金属有机晶态网络结构的设计合成与性能研究报道甚少,这主要是因为非对称柔性联吡啶分子除了保持刚性吡啶N配位指向性外,还能在组装过程中采取多种配位构型等诸多因素,给晶态网络结构的预测带来了一定程度的困难。然而,正是由于非对称柔性联吡啶类分子存在较强的变形能力,也为构筑具有新颖拓扑结构的金属有机晶态网络化合物体系提供了丰富多彩的识别和组装方式。因此,合理地设计合成非对称柔性联吡啶分子建筑块,并在一定程度上实现对具有预期结构和性能的金属有机晶态网络化合物的研究,必将是一项具有挑战性的工作。本论文在综述了联吡啶类金属有机晶态网络结构与性能研究概况的基础上,依据晶体工程学和超分子化学的基本原理,设计合成了六个柔性非对称联吡啶胺有机分子建筑块,旨在组装一系列具有特定和新颖网络结构或具有良好荧光性能的金属有机(超分子)晶态网络化合物,为定向设计合成这类化合物积累一些有价值的实验基础。本论文采用常温自组装和水热溶剂热等合成方法共制备出43个金属有机(超分子)晶态网络化合物,并对其进行了相关的结构和性能表征,所获得的主要研究成果包括以下几方面:1.选用三种柔性非对称联吡啶胺分子,即N-(吡啶-2-甲基)吡啶-3-胺(2,3-L),N-(吡啶-4-甲基)吡啶-3-胺(4,3-L)和N-(吡啶-3-甲基)吡啶-2-胺(3,2-L),通过溶剂热法与CuI反应建构出5个含有[Cu3I2]或[CuI]n簇的金属有机晶态网络化合物,[CuI(2,3-La)]n(1)(2,3-La=N-(pyridin-2-ylmethyl)-N-(pyridin-3-yl) formamide),[Cu1.5I(dmtrz)0.5(PPh3)]n·0.5n(CH3CN)(2)(Hdmtrz=3,5-dimethyl-4H-1,2,4-triazole),[Cu2I2(2,3-Lb)]n(3)(2,3-Lb=N-(pyridin-2-ylmethylene) pyridin-3-amine),[Cu4I4(4,3-L)]n·nH2O (4)和[CuI(3,2-L)]n(5)。化合物1-3中,配体2,3-La,2,3-Lb和dmtrz分别是由2,3-L配体和乙腈分子通过原位反应得到的,它们分别桥联相邻的菱形Cu2I2二聚体、Cu3I2簇及椅式Cu4I4簇形成双链、线形链和(4,4)层状结构;化合物4是以立方Cu4I4簇为次级单元构筑的具有二重穿插的(44·62)拓扑结构;化合物5中,3,2-L分子连接相邻的[Cu2I2]n梯子状双链形成二维层状结构。此外,XPS光谱证明化合物中的Cu2p3/2的电子结合能均为一价氧化态,且荧光分析表明化合物5在475nm处有较强的蓝光发射。2.利用六种柔性非对称联吡啶胺配体,即N-(吡啶-2-甲基)吡啶-3-胺(2,3-L),N-(吡啶-3-甲基)吡啶-2-胺(3,2-L),N-(吡啶-4-甲基)吡啶-2-胺(4,2-L),N-(吡啶-4-甲基)吡啶-3-胺(4,3-L),N-(吡啶-2-甲基)吡啶-2-胺(2,2′-L)和N-(吡啶-3-甲基)吡啶-3-胺(3,3′-L),与硝酸银和高氯酸银通过常温自然挥发法构筑了12个银基金属有机晶态网络化合物,[Ag(L)(NO3)]n[L=2,3-L(6),3,2-L(7),4,2-L(8),4,3-L(9),2,2′-L(n=2)(14),3,3′-L (15)],[Ag(L)(ClO4)]n[L=2,3-L(10),3,2-L(11),4,2-L(12),4,3-L(13)],[Ag2(2,2′-L)2(ClO4)2]n(16),[Ag2(3,3′-L)2(ClO4)2]n·n(CH3CN)(17)。其中,化合物6-13均为螺旋链状结构,化合物14为双核大环结构,化合物15具有二维层状结构,化合物16和17则形成了一维凹凸和波浪形链状结构。此外,对化合物6-17还进行了IR、PXRD、TG表征以及室温下的固态荧光性质测定,同时,对化合物9的圆二色(CD)光谱也做了研究。3.选用五种柔性非对称联吡啶胺分子,即2,2′-L,2,3-L,3,2-L,3,3′-L和4,3-L与HgX2(X=Cl-, Br-和I-)通过常温自然挥发法建构出14个汞基金属有机晶态网络化合物,即[Hg(2,2′-L)X2]n[X=Cl (18)和Br (19)],[Hg(2,3-L)X2]n[X=Br (20)和I(21)],[Hg(3,2-L)Cl2]n(22),[Hg(3,3′-L)Cl2]n(23),{Hg[(3,2-HL)]X3}[X=Br (24)和I(25)],[Hg2I6]2-·2(2,2′-HL)+(26),[HgX4]2-·2(3,3′-HL)+[X=Br (27)和I (28)],[Hg3Cl10]4-·2(4,3-H2L)2+(29),{Hg2(4,3-L)[(4,3-HL)]X5}[X=Br (30)和I (31)]。结构分析表明,化合物18-23是由配体分子桥联HgX2形成的一维线形或螺旋链状结构,化合物24、25、30及31为单核或双核结构,其中Hg(II)离子具有HgNX3或Hg2N2X5(X=Br和I)构型,化合物26-29中的Hg(II)离子与卤素离子键合形成了多样的汞-卤素簇,如[Hg2I6]2-,[HgX4]2-,[Hg3Cl10]4-,且与质子化的非对称联吡啶胺阳离子通过氢键形成离子盐。因此,配体的构型、汞-卤素簇的结构类型及非共价作用力都影响着汞基晶态网络的最终结构。此外,XPS光谱结果显示化合物中的Hg4f7/2电子结合能从含氯、含溴到含碘化合物呈现出逐渐递减的趋势,并且详细探讨了化合物中N1s电子结合能对应于N原子的不同配位环境的关联。4.利用上述六种非对称柔性联吡啶胺分子与硝酸和高氯酸进行常温液相自组装绿色反应,得到了12个超分子晶态网络化合物,(2,2′-H2L)2+·2NO3-(32),(3,2-H2L)2+·2NO3-(33),(4,2-H2L)2+·2NO3-(34),(2,3-H2L)2+·2NO3-(35),(3,3′-H2L)2+·2NO3-(36),(4,3-H2L)2+·2NO3-(37),(2,2′-H2L)2+·2ClO4-(38),(3,2-H2L)2+·2ClO4-(39),(4,2-H2L)2+·2ClO4-(40),(2,3-H2L)2+·2ClO4-(41),(3,3′-H2L)2+·2ClO4-(42),(4,3-H2L)2+·2ClO4-(43)。结构分析表明:所有的化合物中都存在着anion···π作用,不同构型的柔性非对称联吡啶分子在anion···π的作用下组装出多样的超分子花样,同时,结合其他非共价键作用力,如氢键、π···π堆积、C-H···π等作用将上述图案扩展成结构多变的超分子晶态网络。此外,荧光分析结果表明,高氯酸根离子构筑的超分子晶态网络化合物展现出很强的蓝光发射,这为今后设计合成具有优异发光性能的有机超分子晶态网络结构提供了一个思路。
【Abstract】 Metal-organic crystal networks (MOCNs) constructed from bis(pyridyl) ligands haveattracted intensive interests in recent years owing to their alluring structural topologiesand potential applications in photoluminescence, molecular magnet, gas storage,catalysis, as well as chiral separation. Up to now, many outstanding works have beenreported, which provide some useful experiences for designing and synthesizingMOCNs. However, research on the synthesis and property of MOCNs constructed fromflexible unsymmetrical bis(pyridyl) ligands are less concerned owing to the fact that theflexible ligands have many degrees of freedom and hence few conformational restraints,as well as the unpredictable nature of such system. On the contrary, the deformability ofthe flexible unsymmetrical bis(pyridyl) ligands also provides possibility for theassembly of MOCNs with novel topological structures. Therefore, it is still achallenging task to seek for effective synthetic strategies to obtain MOCNs withexpected structures and properties through the rational design of flexible unsymmetricalbis(pyridyl) ligands.We summarized the topological structures and properties of MOCNs based onbis(pyridyl) ligands. According to the principle of crystal engineering andsupramolecular chemistry, we design and synthesize six kinds of flexible unsymmetricalbis(pyridyl) ligands and aim to prepare a series of metal-organic or supramolecularcrystal networks with desired architectures or excellent photoluminescent properties,which then provide some valuable strategies for designing and synthesizing such typesof MOCNs. Accordingly,43metal-organic or supramolecular crystal networks aresynthesized under different solution and hydro(solvo)thermal conditions, which theirarchitectures and properties are also characterized. These researches mainly include thefollowing aspects:1. Three flexible unsymmetrical bis(pyridyl) molecules, namely, N-(pyridin-2-ylmethyl)pyridin-3-amine(2,3-L), N-(pyridin-4-ylmethyl)pyridin-3-amine(4,3-L) and N-(pyridin-3-ylmethyl)pyridin-2-amine (3,2-L) have been employed toreact with CuI through solvothermal reaction, which then led to the formation of fivenew [Cu3I2] or [CuI]nbased MOCNs,[CuI(2,3-La)]n(1)(2,3-La=N-(pyridin-2-ylmethyl)-N-(pyridin-3-yl) formamide),[Cu1.5I(dmtrz)0.5(PPh3)]n·0.5n(CH3CN)(2)(Hdmtrz=3,5-dimethyl-4H-1,2,4-triazole),[Cu2I2(2,3-Lb)]n(3)(2,3-Lb=N-(pyridin-2-ylmethylene)pyridin-3-amine),[Cu4I4(4,3-L)]n·nH2O (4) and [CuI(3,2-L)]n(5). In1-3,the ligands2,3-La,2,3-Lb, and dmtrz-monoanion are obtained from the in situreaction of2,3-L. Adjacent Cu2I2rhomboid dimmers, Cu3I2clusters, as well as the chairlike Cu4I4clusters are connected by the above three in situ generated ligands to formdouble chain, linear chain and (4,4) layer structure. The Cu4I4cubanes in4act as SUBsand are interlinked by the4,3-L ligands to form2-fold interpenetration (44·62) net. Thedouble-stranded [Cu2I2]nladder in5are linked by the3,2-L molecules into layerstructure. The binding energies of the Cu2p3/2level in the XPS spectra are typical forCu(I) oxidation state. Moreover, luminescent property investigation shows that only5exhibits a strong blue emission at475nm.2. Twelve silver(I) based MOCNs assemble from AgX (X=NO3-and ClO4-) salts andsix flexible unsymmetrical bis(pyridyl) ligands, namely, N-(pyridin-2-ylmethyl)pyridin-3-amine (2,3-L), N-(pyridin-3-ylmethyl)pyridin-2-amine (3,2-L), N-(pyridin-4-ylmethyl)pyridin-2-amine (4,2-L), N-(pyridin-4-ylmethyl)pyridin-3-amine (4,3-L),N-(pyridin-2-ylmethyl)pyridin-2-amine (2,2’-L), and N-(pyridin-3-ylmethyl)pyridin-3-amine (3,3’-L) have been obtained, in which6-13exhibit helical chain structure,14presents dinuclear structure,15possesses layer structure,16and17show wavelikechain structure. Moreover, the CD spectrum of9is also studied.3. Solvent reaction of five flexible unsymmetrical bis(pyridyl) ligands of2,2′-L,2,3-L,3,2-L,3,3′-L, and4,3-L with HgX2(X=Cl-, Br-and I-) salts leads to theformation of fourteen mercury(II) based MOCNs, namely [Hg(2,2′-L)X2]n[X=Cl (18)and Br (19)],[Hg(2,3-L)X2]n[X=Br (20) and I (21)],[Hg(3,2-L)Cl2]n(22), [Hg(3,3′-L)Cl2]n(23),{Hg[(3,2-HL)]X3}[X=Br (24) and I (25)],[Hg2I6]2-·2(2,2′-HL)+(26),[HgX4]2-·2(3,3′-HL)+[X=Br (27) and I (28)],[Hg3Cl10]4-·2(4,3-H2L)2+(29),{Hg2(4,3-L)[(4,3-HL)]X5}[X=Br (30) and I (31)].18-23exhibit linear or helical chain motifs assembled from the interconnection betweenHgX2and bis(pyridyl) ligands.24,25,30and31present mono-or dinuclear structures,in which the Hg(II) cations exist in HgNX3and Hg2N2X5(X=Br and I) spheres.26-29are obtained as ionic salts composed of protonated bis(pyridyl) ligandsand variousmercury-halide clusters,[HgX4]2-(X=Br-and I-),[Hg2I6]2-,[Hg3Cl10]4-. The structuraldiversities and evolutions of these architectures can be attributed to the diversemercury-halide clusters, the ligand conformation (cis-trans, trans-cis, trans-trans) aswell as the noncovalent interactions. Moreover, the binding energies of the Hg4f7/2level in the XPS spectra present regular decrease from Cl-containing, Br-containing, toI-containing complexes. For the N1s, the different binding energies in the XPS spectracan be attributed to the N atoms with different chemical environments.4. Self-assembly of different inorganic acids (HNO3and HClO4) and theaforementioned six flexible unsymmetrical bis(pyridyl) ligands results in the formationof twelve supramolecular networks,(2,2′-H2L)2+·2NO3-(32),(3,2-H2L)2+·2NO3-(33),(4,2-H2L)2+·2NO3-(34),(2,3-H2L)2+·2NO3-(35),(3,3′-H2L)2+·2NO3-(36),(4,3-H2L)2+·2NO3-(37),(2,2′-H2L)2+·2ClO4-(38),(3,2-H2L)2+·2ClO4-(39),(4,2-H2L)2+·2ClO4-(40),(2,3-H2L)2+·2ClO4-(41),(3,3′-H2L)2+·2ClO4-(42),(4,3-H2L)2+·2ClO4-(43). It is interesting to note that anion···π interactions are alldetected in the twelve supramolecular networks. Diverse supramolecular patterns areobtained from the bis(pyridyl) ligands and inorganic acids with the assistance of varioussupramolecular interactions, such as hydrogen bonds, π···π stacking, as well as C-H···π.Moreover, the networks constructed from the perchlorate exhibit strong blue emission atroom temperature.