由羧酸配体和铁(Ⅱ)构筑的两个过渡金属配位聚合物的结构、表征和性质

采用水热法合成了2个铁的过渡金属配位聚合物[Fe(Medpq)(BDC)H₂O]_n(1)和{[Fe(Medpq)(QUI)H₂O]·2H₂O}_n(2)(Medpq=2-methyldipyrido[3,2-f:2',3'-h]quinoxaline; H₂BDC=terephthalic acid; H₂QUI=2,3-pyridinedicarboxylic acid),并对其进行了元素分析、红外光谱和热重表征,并用X射线单晶衍射测定结构。2个配位聚合物中的中心铁(Ⅱ)离子,都呈现一个稍微扭曲的八面体几何构型。     

基于双咪唑配体的一维银配位聚合物的合成、晶体结构和表征

通过水热法合成了1个一维配位聚合物[Ag(1,2-bix)].HL,并对该化合物进行了元素分析、红外和单晶X-射线表征(1,2-bix=1,2-(二亚甲基苯)二咪唑配体,HL=反式-4,4′-二羧基偶氮苯阴离子)。该化合物属于三斜晶系,空间群P1,晶胞参数a=0.937 80(5)nm,b=1.119 91(16)nm,c=1.356 36(10)nm,α=102.923(8)°,β=91.751(5)°,γ=110.792(10)°,V=1.288 5(2)nm3,Z=2,C28H23AgN6O4,Mr=615.39,Dc=1.586 g.cm-3,F(000)=624,μ(Mo Kα)=0.829 mm-1,R=0.040 7,wR=0.102 0。在该化合物中,双咪唑配体连接着中心的Ag(Ⅰ)原子形成了一维链状结构。二羧酸配体之间通过O-H…O键形成另一种一维链状结构,两种类型的链以相互垂直的方式延伸。此外,我们还仔细研究了该化合物的荧光性质。     

由羧酸配体和铁(Ⅱ)构筑的两个过渡金属配位聚合物的结构、表征和性质

采用水热法合成了2个铁的过渡金属配位聚合物[Fe(Medpq)(BDC)H₂O]_n(1)和{[Fe(Medpq)(QUI)H₂O]·2H₂O}_n(2)(Medpq=2-methyldipyrido[3,2-f:2',3'-h]quinoxaline; H₂BDC=terephthalic acid; H₂QUI=2,3-pyridinedicarboxylic acid),并对其进行了元素分析、红外光谱和热重表征,并用X射线单晶衍射测定结构。2个配位聚合物中的中心铁(Ⅱ)离子,都呈现一个稍微扭曲的八面体几何构型。     

基于一种柔性双咪唑和不同双羧基配体构筑的两例镉(Ⅱ)的配位聚合物

在水热条件下合成了2个新颖的镉(Ⅱ)配位聚合物:[Cd₂(μ2-H₂O)(1,5-Bip)(Tpa)₂]_n(1)和[Cd(1,5-Bip)(Oba)]_n(2)(H₂Oba=4,4''-二羧酸二苯甲醚,H₂Tpa=对苯二甲酸,1,5-Bip=1,5-二(咪唑基)戊烷)。并通过X射线单晶衍射,粉末XRD、红外光谱、元素分析以及热重分析对其结构进行表征。单晶解析结果表明:配位聚合物1是一个单节点5连接(4⁶.6⁴)拓扑三维空间网络结构,配位聚合物2是一个二维的(4,4)网格层状结构。另外,研究了2个配位聚合物在室温下的热稳定和荧光性能。     

两个基于4-咪唑羧酸配体超分子配位聚合物的合成、结构和性质

以含4-咪唑和羧酸基团的双功能基团4-咪唑基苯甲酸(HL₁)为配体,用水热法合成了2个超分子化合物[Cd(L₁)(HL₁)I] (1)和[Co₂(L₁)₄(H₂O)₈] (2),并进行了元素分析、红外、热重、粉末衍射及X-射线单晶衍射等表征。晶体结构解析结果表明:配合物1属于单斜晶系,P2₁/c空间群,L₁-配体连接Cd(Ⅱ)离子成一维链,这些一维链通过氢键连接成三重贯穿的α-Po结构的超分子聚合物;配合物2不对称结构单元中,存在3种不同的金属Co(Ⅱ)中心单核分子,这些相互独立的分子单元通过丰富的氢键连接成三维的聚合物。同时,对配合物1室温下的固体荧光性质和配合物2对气体的吸附性能进行了研究。     

两个基于4-咪唑羧酸配体超分子配位聚合物的合成、结构和性质

以含4-咪唑和羧酸基团的双功能基团4-咪唑基苯甲酸(HL1)为配体,用水热法合成了2个超分子化合物[Cd(L1)(HL1)I](1)和[Co2(L1)4(H2O)8](2),并进行了元素分析、红外、热重、粉末衍射及X-射线单晶衍射等表征。晶体结构解析结果表明:配合物1属于单斜晶系,P21/c空间群,L1-配体连接Cd( Ⅱ)离子成一维链,这些一维链通过氢键连接成三重贯穿的α-Po结构的超分子聚合物;配合物2不对称结构单元中,存在3种不同的金属Co( Ⅱ)中心单核分子,这些相互独立的分子单元通过丰富的氢键连接成三维的聚合物。同时,对配合物1室温下的固体荧光性质和配合物2对气体的吸附性能进行了研究。     

三个包含四羧酸配体的配位聚合物的合成及其催化性质

利用水热合成方法,选用5-((3,5-二羧基苯基)氨基)苯-1,3-二甲酸配体(H₄adip)与菲咯啉(phen)、2,2′-联吡啶(bipy)或双(4-吡啶)胺(bpa),分别与 ZnCl₂和 CoCl₂·6H₂O 在 160 ℃温度下反应,合成了 3 个三维配位聚合物{[Zn₂( μ₆-adip)(phen)₂]·4H₂O}_n (1)、{[Co₂( μ₆-adip)(bipy)₂]·4H₂O}_n (2)和[Co₂( μ₄-adip)( μ-bpa)₂]_n (3)。这些配合物为稳定的晶体。通过红外光谱、元素分析、热重分析和单晶X射线衍射分析对其进行了表征。单晶X射线衍射分析表明,3个配合物的晶体属于正交晶系Pnna (1和2)和P2₁2₁2 (3)空间群。配合物 1~3都呈三维结构。考察了这些配合物在 Henry反应中的催化活性。研究表明,配合物 3在 70 ℃下对 Henry反应表现出有效的催化活性。同时对反应参数进行了优化,对底物范围也进行了研究。     

含咪唑基配体镉配位聚合物的合成、结构及荧光性质

利用柔性含咪唑基配体1,3,5-三(咪唑-1-甲基)苯(L)与硫酸镉在溶剂热条件下反应,通过反应条件控制得到了2个配位聚合物{[Cd(L)(EG)0.5(H2O)(SO4)]·EG·H2O}n(1)和[Cd(L)(EG)(SO4)]n(2)(EG=乙二醇)。并利用元素分析、红外光谱、X射线单晶衍射等方法对其进行了表征。配合物1中配体L连接Cd(Ⅱ)形成一维链状结构,而配合物2中配体L与Cd(Ⅱ)配位形成二维网状结构,并进一步通过硫酸根桥联形成三维结构。有趣的是,EG分子在配合物1中连接链内的2个Cd(Ⅱ),而在配合物2中作为端基与1个Cd(Ⅱ)配位,硫酸根离子在1中作为端基配位,而在2中则以桥联方式连接2个Cd(Ⅱ)。研究了配合物的荧光性质及其热稳定性。     

三个二羧酸配体配位聚合物的合成、结构表征和荧光性质

以羧酸配体 2,2''-(1,4-亚苯基双(亚苯基))双(硫二基)二苯甲酸(H₂L¹)和 2,2''-(2,3,5,6-四甲基-1,4-亚苯基)双(亚甲基）双(硫二基)二苯甲酸(H₂L²)分别与金属盐反应,通过溶剂热方法合成了 3个配位聚合物：{[Ni(L¹)(H₂O)₄]·2H₂O}_n (1)、[Zn(L¹)(DMA)₂]_n(2)和[Co(L²)(DMF)₂]_n (3),其中DMA=N,N-二甲基乙酰胺,DMF=N,N-二甲基甲酰胺。对配合物1~3进行了单晶X射线衍射、元素分析、红外光谱、热重分析、粉末X射线衍射和固体紫外可见光谱测试和表征。单晶X射线衍射表明：3个配合物均为一维锯齿形链状结构,并通过氢键作用形成三维骨架,且配体均表现为反式构象。此外,对配合物2固态荧光性质进行了研究。     

混合配体构筑的配位聚合物的合成、结构与荧光性质

在溶剂热条件下,利用Cd（Ⅱ）、Co（Ⅱ）在混配体体系下合成出3个结构新颖的配位聚合物[Cd₃（pic）₄（H₂bmimb）]_n（1）,[Co₃（pic）₄（H₂bmimb）]_n（2）和[Cd₂（1,2-mbix）（pic）₂（H₂O）₂]_n（3）（pic=5-苯基间苯二甲酸;H₂bmimb=1,4-二（（2-甲基咪唑）亚甲基）苯;1,2-mbix=1,2-二（（2-甲基咪唑）亚甲基）苯）,并通过单晶X射线衍射、红外光谱、热重分析、元素分析、粉末X射线衍射和荧光光谱等对配合物进行了表征。配合物1和2中金属离子Cd²⁺、Co²⁺均与pic配体形成了三维阴离子骨架,双质子化的双咪唑配体位于骨架中平衡骨架电荷。配合物3中,Cd²⁺金属中心与pic、1,2-mbix配体配位形成一维链,链与链之间通过苯环间的π…π堆积形成二维层,进而通过氢键形成三维超分子结构。配合物1和3表现出良好的荧光性质。     

1-D Chain lanthanide coordination polymers based on mixed 2,4-dichlorophenoxyacetate and 1,10-phenanthroline ligands: crystal structures and luminescent properties

Two new isostructural 1-D lanthanide coordination polymers, {[Ln(2,4-dcp)₃(phen)] _n [(Ln?=?Eu (1); Tb (2)], [2,4-dcp?=?2,4-dichlorophenoxyacetate, phen?=?1,10-phenanthroline], were obtained under hydrothermal conditions and characterized by IR spectroscopy, elemental analyses, thermogravimetry analyses, powder X-ray diffraction, and single-crystal X-ray diffraction. Both structures exhibit similar 1-D infinite chains with a {Ln₂(2,4-dcp)₆(phen)₂} dimeric repeat unit, with lanthanides in an eight-coordinate environment. The results of thermal analysis indicate that 1 and 2 are quite stable to heat. 3-D fluorescence spectra of 1 and 2 were detected at room temperature under excitation and the emission wavelengths of 250–460?nm and 420–750?nm with the same interval of 5?nm, respectively. Interestingly, 1 and 2 possess longer fluorescence lifetimes than other complexes (τ?=?1.61?ms for 1 at 611?nm; 1.79?ms for 2 at 543?nm).     

Syntheses,structures, and photoluminescence of three cadmium(II) coordination polymers with flexible bis(benzimidazole) ligands

Three cadmium(II) coordination polymers, [CdBr₂(L₁)] _n (1), [CdI₂(L₂)] _n (2), and Cd₂Br₄(L₃)₂ (3), where L₁?=?1,3-bis(5,6-dimethylbenzimidazole)propane, L₂?=?1,4-bis(5,6-dimethylbenzimidazole)butane, and L₃?=?1,6-bis(5,6-dimethylbenzimidazole)hexane, have been synthesized by hydrothermal methods and characterized by elemental analyses, IR spectra, TGA, PXRD, and X-ray crystallographic diffraction. Complex 1 contains a 1-D helical chain in which CdBr₂ units are linked by L₁. For 2, each CdI₂ is connected by two different conformations of L₂ to form a 1-D zigzag chain. For 3, each CdBr₂ is linked by L₃ bridges to afford a binuclear structure. These results indicate that the spacer length of the ligands play important roles in assembly of Cd(II) coordination polymers. Thermogravimetric analyses and solid-state luminescent properties of the complexes have also been investigated.     

Synthesis,structure, thermostability and luminescence properties of ZnII and CdII coordination polymers based on dimethysuccinate and flexible 1,4‐bis(imidazol‐1‐ylmethyl)benzene ligands

The design and synthesis of functional coordination polymers is motivated not only by their structural beauty but also by their potential applications. Zn^II and Cd^II coordination polymers are promising candidates for producing photoactive materials because these d¹⁰ metal ions not only possess a variety of coordination numbers and geometries, but also exhibit luminescence properties when bound to functional ligands. It is difficult to predict the final structure of such polymers because the assembly process is influenced by many subtle factors. Bis(imidazol‐1‐yl)‐substituted alkane/benzene molecules are good bridging ligands because their flexibility allows them to bend and rotate when they coordinate to metal centres. Two new Zn^II and Cd^II coordination polymers based on mixed ligands, namely, poly[[μ₂‐1,4‐bis(imidazol‐1‐ylmethyl)benzene‐κ²N³:N^3′]bis(μ₃‐2,2‐dimethylbutanoato‐κ³O¹:O⁴:O^4′)dizinc(II)], [Zn₂(C₆H₈O₄)₂(C₁₄H₁₄N₄)]_n, and poly[[μ₂‐1,4‐bis(imidazol‐1‐ylmethyl)benzene‐κ²N³:N^3′]bis(μ₃‐2,2‐dimethylbutanoato‐κ⁵O¹,O^1′:O⁴,O^4′:O⁴)dicadmium(II)], [Cd₂(C₆H₈O₄)₂(C₁₄H₁₄N₄)]_n, have been synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. Both complexes crystallize in the monoclinic space group C2/c with similar unit‐cell parameters and feature two‐dimensional structures formed by the interconnection of S‐shaped Zn(Cd)–2,2‐dimethylsuccinate chains with 1,4‐bis(imidazol‐1‐ylmethyl)benzene bridges. However, the Cd^II and Zn^II centres have different coordination numbers and the 2,2‐dimethylsuccinate ligands display different coordination modes. Both complexes exhibit a blue photoluminescence in the solid state at room temperature.     

Syntheses,structures, and fluorescent properties of two uranium coordination polymers with carboxylic acids

Two U(VI)-containing coordination polymers, (UO₂)₂O₂(Suc)(2,2′-bipy)₂ (1) and UO₂(BC)₂(DMF) (2) (2,2′-bipy?=?2,2′-bipyridine, H₂Suc?=?succinic acid, HBC?=?benzoic acid, DMF?=?N,N-dimethylformamide), have been synthesized and characterized via elemental analysis, infrared spectroscopy, UV-Vis spectroscopy, and single-crystal X-ray diffraction. Structural analyses show that 1 is a 1-D chain coordination polymer in which U(VI) ions are connected by succinic acid ligand and the 1-D chain is connected into a 3-D supramolecular network by C?H···O hydrogen bonds between carbon of 2,2′-bipyridine and uranyl oxygen. For 2, monomeric entities are further assembled into a 1-D supramolecular network by C–H···O hydrogen bonds between carbon of DMF molecule and coordinated carboxylate oxygen. Thermogravimetric analyses and photoluminescent properties of 1 and 2 are discussed.     

Hydrothermal synthesis,crystal structures,and photoluminescent properties of two cadmium(II) coordination polymers derived from dicarboxylates and N-donor ligands

Two metal coordination polymers, [Cd(ipa)(L₁)(H₂O)]_n (1) and [Cd(ipa)(L₂)]_n (2) [H₂ipa?=?isophthalic acid, L₁?=?3,5-bis(imidazole-1-yl)pyridine and L₂?=?3,5-bis(benzoimidazo-1-ly)pyridine], have been synthesized and structurally characterized by IR, elemental analysis, XRD, and X-ray single-crystal diffraction. Complex 1 shows a twofold cds topological net and 2 features a 3-D pcu topological net. Luminescent properties of 1 and 2 were investigated in the solid state at room temperature.     

Synthesis of two luminescent coordination polymers based on self‐assembly of Zn(II) with polycarboxylic acids ligands and heteroaromatic N‐donor

Using the principles of molecular self‐assembly, two novel zinc complexes {[Zn(phth)(bipy)(H₂O)][Zn(phth)(bipy)]·H₂O}_n (1) and [Zn(1,2,4‐btc)(bipy)(H₂O)·2H₂O]_n (2) were obtained by hydrothermal reaction of Zn(CH₃COO)₂·2H₂O with phthalic acid (phth), 1,2,4‐benzenetricarboxylic acid (1,2,4‐btc) and 2,2′‐bipyridine (bipy) respectively, and characterized by single‐crystal X‐ray diffraction. The crystal structures reveal that both complexes form one‐dimensional chain structures, and the zinc ions are five‐coordinated; there are two types of metal environment in the structure of the complex 1. The photophysical properties have been investigated with fluorescence excitation and emission spectra. Copyright © 2005 John Wiley & Sons, Ltd.     

Syntheses, structures and magnetic properties of five iron(II) coordination polymers with flexible bis(imidazole) and bis(triazole) ligands

Five iron(II) coordination polymers, {[Fe(bte)₂(NCS)₂][Fe(bte)(H₂O)₂(NCS)₂]}_n (1), [Fe(bime)(NCS)₂]_n (2), [Fe(bime)(dca)₂]_n (3), [Fe(bime)₂(N₃)₂]_n (4) and [Fe(btb)₂(NCS)₂]_n (5), were synthesized using the flexible ligands 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), 1,2-bis(imidazol-1-yl)ethane (bime) and 1,4-bis(1,2,4-triazol-1-yl)butane (btb), together with NCS⁻, dicyanamide (dca) and N₃⁻. The compound 1 contains two kinds of motifs (double chain and single chain) and forms a three-dimensional hydrogen bonded network; 2 and 3 contain one-dimensional triple chains; and 4 and 5 form two-dimensional (4, 4) networks. The coordination anions (NCS⁻, dca and N₃⁻) and the structural characteristics of the ligands (bte, bime and btb) play an important role in the assembly of the topologies. Magnetic studies reveal that 1-5 remain in the high-spin state over the whole temperature range 2-300 K and no detectable spin-crossover is observed.     

Syntheses,structures, luminescent and magnetic properties of two coordination polymers based on a fl exible multidentate carboxylate ligand

Two coordination polymers,{[Cu_3(tci)_2(DMAc)_3]-6DMAc 2H_2O}_n(1) and {[Cu_3(tci)_2(tpt)_2(H_2O)_2].2DMAc-2H_2O}_n(2)(H_3tci = tris(2-carboxyethyI)isocyanurate,tpt = 2,4,6-tris(4-pyridyl)-l,3,5-triazine,DMAc = N,/V-dimethylacetamide),have been constructed under solvothermal conditions.Both polymers were structurally characterized by single crystal X-ray diffraction,elemental analyses,IR spectra,thermogravimetric(TG) analyses and powder X-ray diffraction(RXPD).1 shows a(3,4)-connected 2D layer structure comprising Cu_2(CO_2)4 paddle-wheel units,which are further bridged by C-H…O interactions to give a 3D supramolecular network.The introduction of tpt produces different framework for 2 that comprises a dinuclear and a mononuclear Cu(Ⅱ) building units,which are further bridged together by tci~(3-) and tpt ligands to give a 4-connected 2D topological net.Adjacent 2D layers are packed together via C-H…O interactions and π…π stacking interactions to form a 3D supramolecular structure.In addition,the luminescent properties and the solid-state UV-vis spectra of 1 and 2 were explored.Furthermore,antiferromagnetic exchange interactions were unveiled in the Cu_2(COO)_4 units of 1.     

Four Co(II)/Zn(II) coordination polymers with a multidentate ligand: syntheses,structures, thermal,and photoluminescent properties

Two pairs of isostructural transition metal coordination polymers, {[Co(L)(H₂O)]_n} (1) and {[Zn(L)(H₂O)]_n} (3), {[Co(L)(4,4′-bipy)(H₂O)]·H₂O}_n (2) and {[Zn(L)(4,4′-bipy)(H₂O)]·H₂O}_n (4) (H₂L = N-pyrazinesulfonyl-glycine acid and 4,4′-bipy = 4,4′-bipyridine), have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental and thermogravimetric analyses. The structures show that 1 and 3 display 2-D polymeric grid frameworks with a 3-connected (4, 8²) topology. 2 and 4 also exhibit a 2-D polymeric grid structure, but are constructed by a 4-connected (4, 4) topology. The adjacent 2-D polymeric grid frameworks for 1–4 are further linked by hydrogen bonding O–H?O interactions to form 3-D supramolecular interweaved orderly networks. The fluorescent properties of 3 and 4 were investigated in the solid state.     

Two new cadmium(II) coordination polymers based on imidazole‐containing ligands: synthesis,structural characterization and fluorescence properties

The judicious selection of suitable ligands is vitally important in the construction of novel metal–organic frameworks (MOFs) with fascinating structures and interesting properties. Recently, imidazole‐containing multidentate ligands have received much attention. Two new Cd^II coordination frameworks, namely, poly[tris{μ‐1,4‐bis[(1H‐imidazol‐1‐yl)methyl]benzene‐κ²N³:N^3′}tetrakis(nitrato‐κ²O,O′)dicadmium], [Cd₂(NO₃)₄(C₁₄H₁₄N₄)₃]_n, (I), and poly[[bis{μ₃‐1,3,5‐tris[(1H‐imidazol‐1‐yl)methyl]benzene‐κ³N³:N^3′:N^3′′}cadmium] hexafluorosilicate], {[Cd(C₁₈H₁₈N₆)₂](SiF₆)}_n, (II), have been synthesized and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. In polymer (I), the 1,4‐bis[(1H‐imidazol‐1‐yl)methyl]benzene ligand bridges Cd²⁺ ions with a distorted seven‐coordinated pentagonal bipyramidal geometry, forming a one‐dimensional ladder chain, and the nitrate anions coordinate to the Cd²⁺ ions in a terminal bidentate fashion. In the crystal, adjacent chains are further connected by C—H…O hydrogen bonds to generate a two‐dimensional (2D) supramolecular structure. Polymer (II) exhibits a 2D layered structure in which 1,3,5‐tris[(1H‐imidazol‐1‐yl)methyl] benzene ligands join Cd²⁺ centres having a six‐coordinated octahedral structure. The layers are connected by hexafluorosilicate anions via C—H…F hydrogen‐bond interactions, giving rise to a three‐dimensional supramolecular network structure in the solid state. In addition, powder X‐ray diffraction (PXRD) patterns were recorded, thermogravimetric analyses (TGA) carried out and fluorescence properties investigated.