Cd(II) and Cu(II) coordination polymers based on a multidentate N-donor ligand: syntheses,crystal structures,optical band gaps,and photoluminescence

Four Cd(II)- and Cu(II)-containing coordination polymers (CPs) based on a multidentate N-donor ligand and varied dicarboxylate anions, [Cd(3,3′-tmbpt)(p-bdc)]·2.5H₂O (1), [Cd(3,3′-tmbpt)(m-bdc)]·2H₂O (2), [Cu(3,3′-tmbpt)(m-bdc)]·H₂O (3), and [Cu(3,3′-tmbpt)(p-bdc)]·2H₂O (4), where 3,3′-tmbpt = 1 ? ((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole, p-H₂bdc = 1,4-benzenedicarboxylic acid, and m-H₂bdc = 1,3-benzenedicarboxylic acid, have been prepared hydrothermally. The structures of the compounds were determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra and elemental analyses. Compound 1 exhibits a 3-D twofold interpenetrating framework with a 6⁵·8 CdSO₄ topology. Compound 2 is a 2-D layer containing meso-helical chains with a 4⁴·6² sql topology. Compound 3 shows a 1-D → 3-D interdigitated architecture while 4 displays a 2-D → 3-D interdigitated architecture. The structural differences of the compounds indicate that the dicarboxylate anions and the central metal ions play important roles in the resulting structures of CPs. Optical band gaps and solid-state photoluminescent properties have also been studied.     

Two Nickel(II) Coordination Polymers Based on Tri(p‐carboxyphenyl) phosphane Oxide with Highly Selectively and Sensitively Detection of Acetone

Two nickel(II) coordination polymers, namely, {[Ni_1/2(TPO)_1/3(bib)_1/2(H₂O)] · H₂O}_n ( 1 ), and [Ni(HTPO)(bpy)(H₂O)₂]_n ( 2 ), were assembled from tripodal ligand of tripodal tri(p‐carboxyphenyl) phosphane oxide (H₃TPO) and two N‐donors [bib = 1,4‐bis(imidazolyl)benzene, and bpy = 4,4′‐bipyridine]. Their structures were determined by single‐crystal X‐ray diffraction analysis and further characterized by elemental analysis, IR spectra, powder X‐ray diffraction (PXRD), and thermogravimetric analysis (TGA). Structural analysis reveals that complex 1 is an interestingly 3D (3,4)‐connected {10³}₂{10⁶}₃ net, whereas complex 2 is a 1D polymeric chain, which was further expanded into a 3D supramolecular structure through hydrogen bonds. Luminescent sensing measurements show two nickel CPs can selectively and sensitively detect for acetone from normal solvents (DMF, DMA, DMSO, MeOH, EtOH, CH₃CN, H₂O, and N‐butanol).     

Construction of Cd(II) complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole and 1,4-benzenedicarboxylate

Three new Cd(II) complexes incorporating both 2-(1H-imidazol-1-methyl)-1H-benzimidazole (imb) and 1,4-benzenedicarboxylate (bdic^2?), [CdCl(bdic)_1/2(imb)₂]_n (1), {[Cd(bdic)(imb)(H₂O)]·DMF·2H₂O}_n (2), and [Cd(bdic)(imb)]·3H₂O}_n (3), have been prepared and structurally characterized by single crystal X-ray diffraction. Bdic^2? anions connect the?Cd-imb-Cd-imb?chains leading to a 2-D structure of 1. Bdic^2?(A) and bdic^2?(B) anions link the binuclear [Cd₂(imb)₂(H₂O)₂] units forming a 2-D structure of 2. Complex 3 features a 2-D structure involving supramolecular “double-layer” motifs. IR spectra and thermogravimetric curves are consistent with the results of the X-ray crystal structure analysis; 1–3 exhibit good fluorescence in the solid state at room temperature.     

Syntheses,crystal structures,and fluorescent properties of 2-D Cd(II) complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole and 1,2,4,5-benzenetetracarboxylate ligands

Two new complexes, {[Cd(btec)_0.5(imb)(CH₃OH)]·CH₃OH}_n (1) and {[Cd(btec)_0.5(H₂btec)]·(H₂imb)·2H₂O}_n (2) (H₄btec = 1,2,4,5-benzenetetracarboxylic acid, imb = 2-(1H-imidazol-1-methyl)-1H-benzimidazole), have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. Both complexes exhibit 2-D network structures. In 1, each 1,2,4,5-benzenetetracarboxylate links four Cd²⁺ cations, and each Cd²⁺ cation connects two 1,2,4,5-benzenetetracarboxylates, to form a 2-D layer, with the imb ligands located on each side of the 2-D layer. In 2, there are two kinds of 1,2,4,5-benzenetetracarboxylates in the structure. One kind is completely deprotonated and acts as hexadentate linkers, leading to a 2-D layer. The other kind is only doubly deprotonated and decorates each side of the 2-D layer. In 2, imb is protonated, forming (H₂imb)²⁺ cations that only cocrystallize with the negatively charged Cd coordination polymer ({[Cd(btec)_0.5(H₂btec)]^2?}_n), but does not coordinate to the Cd²⁺ cations. IR spectra, PXRD patterns, thermogravimetric analyses, and fluorescent properties of 1 and 2 have also been determined.     

Nuclease activity of redox/non-redox active binuclear transition metal mixed-polypyridine complexes: [M2(1,4-tpbd)(diimine)2(H2O)2]4+, M = Zn,Co, Ni,Cd, diimine = phen,bpy, dafo

Seven new transition metal complexes formulated as [M₂(1,4-tpbd)(diimine)₂(H₂O)₂]⁴⁺ [M = Zn, Co, Ni, Cd; 1,4-tpbd = N,N,N′,N′-tetrakis(2-pyridylmethyl)benzene-1,4-diamine; diimine is a N,N-donor heterocyclic base like 1,10-phenanthroline (phen), 2,2′-bipyridine (bpy), 4,5-diazafluoren-9-one (dafo)] have been synthesized and structurally characterized by X-ray crystallography: [Zn₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (1), [Zn₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (2), [Co₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (3), [Ni₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (4), [Ni₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (5), [Ni₂(1,4-tpbd)(dafo)₂(H₂O)₂]⁴⁺ (6) and [Cd₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (7). Single crystal diffraction reveals that the metals in the complexes are all in a distorted octahedral geometry. The interactions of the seven complexes with calf thymus DNA (CT-DNA) have been investigated by UV absorption, fluorescence, circular dichroism spectroscopy and viscosity measurements. The apparent binding constants (K_app) are calculated to be 5.2?×?10⁵ M^?1 for 1, 1.05?×?10⁵ M^?1 for 2, 5.76?×?10⁵ M^?1 for 3, 4.57?×?10⁵ M^?1 for 4, 1.29?×?10⁵ M^?1 for 5, 1.7?×?10⁵ M^?1 for 6, 2.53?×?10⁵ M^?1 for 7, the binding propensity to the calf thymus DNA in the order: 3 (Co-phen) > 1 (Zn-phen) > 4 (Ni-phen) > 7 (Cd-phen) > 6 (Ni-dafo) > 5 (Ni-bpy) > 2 (Zn-bpy). Furthermore, these complexes display efficient oxidative cleavage of supercoiled DNA; the Zn(II)/H₂O₂ and Cd(II)/H₂O₂ systems efficiently cleave DNA attributed to the peroxide ion coordinated to the Zn(II) and Cd(II), which enhanced their nucleophilicity, this is rare.     

基于5,5′-亚甲基二间苯二甲酸及1,2-双(咪唑基-1-甲基)苯的Zn~(2+)、Co~(2+)配位聚合物的合成及晶体结构

水热条件下,合成了2个三维配位聚合物{[Zn4(L)2(o-bix)2]·2H2O}n(1),{[Co4(L)2(o-bix)2]·2H2O}n(2)(H4L=5,5′-亚甲基二间苯二甲酸,o-bix=1,2-双(咪唑基-1-甲基)苯),并通过红外、热重和X-射线单晶衍射进行了表征。X-射线衍射结果表明这2个化合物具有相似的结构。在1个不对称单元中,化合物包含2个不同配位环境的金属离子,1个L4-配体,1个o-bix分子以及1个游离的溶剂水分子。中心金属离子分别采用畸变的四面体和四方锥构型,形成两类双核单元,然后通过全部脱质子的L4-形成3D孔洞结构,o-bix配体通过连接两类双核金属原子填充于孔洞之中,形成3D紧密堆积结构。对化合物的红外和热重性质进行了表征。     

Synthesis,Characterization, and Thermostability of Four Novel Cadmium(II) Coordination Polymers with Mixed Ligands

Four novel mixed‐ligand complexes were obtained from the reaction of maleic acid, diimine chelating ligands and Cd(OH)₂ or CdO in a mixed solvent of water and methanol. The complexes were characterized by IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. The results show that all the four complexes are coordination polymers. [Cd(phen)(H₂O)(male)]_n · 2nH₂O ( 1 ) and [Cd(bipy)(H₂O)(male)]_n · 2nH₂O ( 2 ) (male = maleate; phen = 1, 10‐phenanthroline, bipy = 2, 2′‐bipyridine) are isomorphic, and the asymmetric unit is constructed by one Cd^II atom, a maleate group, a diimine ligand and two crystal water molecules. Each maleate group links two Cd^II atoms in a bis(bidentate) chelating mode, resulting in a 1D helical chain. Within [Cd(phen)(H₂O)₂(male)]_n · 2nH₂O ( 3 ), the maleate group bridges two Cd^II atoms in a bis(monodentate) chelating mode into a 1D helical chain along the [100] direction. The helical chain is decorated by phen groups alternatively at the two sides, and each phen plane of one chain is inserted in the void space between two adjacent phen ligands from an adjacent chain, resulting in a double zipper‐like chain. The asymmetric unit of [Cd₂(phen)₂(male)₂]_n ( 4 ) contains a Cd^II cation, one phen molecule, and a maleate group, and one bridging maleate group links three Cd^II atoms resulting in a 2D layer extending in [011] plane. The 2D networks are constructed by four kinds of rings formed by the central metal atom and maleate dianion. The thermostabilities of the four complexes were investigated.     

Four Zn(II)/Cd(II) coordination polymers derived from isomeric benzenedicarboxylates and 1,6-bis(triazol)hexane ligand: synthesis,crystal structure,and luminescent properties

Four coordination polymers, [Zn(o-bdc)(bth)_0.5(H₂O)] _n (1), [Cd(o-bdc)(bth)_0.5(H₂O)] _n (2), [Zn(m-bdc)(bth)] _n (3), and [Cd(p-bdc)(bth)?·?(H₂O)₂] _n (4) (where o-bdc?=?1,2-benzenedicarboxylate, m-bdc?=?1,3-benzenedicarboxylate, p-bdc?=?1,4-benzenedicarboxylate, and bth?=?1,6-bis(triazol)hexane), have been hydrothermally synthesized and structurally characterized. Both 1 and 2 are isostructural, featuring two binodal architectures: (6³)(6⁵·8) topology in terms of o-bdc and Zn^II/Cd^II as three- and four-connected nodes. Complex 3 shows a 2-D (4,4) network with the Zn?···?Zn?···?Zn angle of 57.84°, whereas 4 exhibits planar 2-D (4,4) network. These 2-D networks of 3 and 4 are extended by supramolecular interactions, such as CH?···?π/π–π stacking and hydrogen-bonding into 3-D architecture. A structural comparison of these complexes demonstrates that the dicarboxylate building blocks with different dispositions of the carboxyl site play a key role in governing the coordination motifs as well as 3-D supramolecular lattices. Solid-state properties such as photoluminescence and thermal stabilities of 1–4 have also been studied.     

4个Cd(Ⅱ)配位聚合物:辅助配体对晶体结构以及荧光性能的影响

采用溶剂热的方法,将配位模式丰富的多羧酸有机配体5-（2-硝基-4-羧基苯氧基）-间苯二甲酸（H₃ncpoi）与Cd²⁺离子以及不同的辅助配体原位组装而成4个新的配位聚合物晶体：[Cd（Hncpoi）（2,2''-bpy）（H₂O）]_n（1）,{[Cd₂（Hncpoi）₂（bpyp）（H₂O）₄]·3H₂O}_n（2）,{[Cd₂（Hncpoi）₂（azpy）（H₂O）₂]·2H₂O}_n（3）,{[Cd₂（Hncpoi）₂（dpe）（H₂O）₂]·2H₂O}_n（4）,其中H₃ncpoi为5-（2-硝基-4-羧基苯氧基）-间苯二甲酸,2,2''-bpy为2,2''-联吡啶,bpyp为1,4-二-吡啶基-4-亚甲基-哌嗪,azpy为4,4''-偶氮吡啶,dpe为1,2-二-（4-吡啶基）乙烯。对4个配合物进行了X射线单晶衍射、粉末衍射,元素分析、热重、荧光光谱等表征。X射线单晶结构分析表明,配合物1,2具有一维链状结构,而配合物3,4则具有二维（4,4）格子层状结构,一维链和二维层之间通过分子间作用力连接成三维超分子结构。进一步研究表明,辅助配体的构型、配位方式等对晶体结构具有决定性作用。与此同时,对几个配合物的荧光光谱进行分析,发现不同的辅助配体对配合物的荧光性能有着显著的影响。     

四个Cd(Ⅱ)配位聚合物:辅助配体对晶体结构以及荧光性能的影响

采用溶剂热的方法,将配位模式丰富的多羧酸有机配体5-(2-硝基-4-羧基苯氧基)-间苯二甲酸(H3ncpoi)与Cd~(2+)离子以及不同的辅助配体原位组装而成4个新的配位聚合物晶体:[Cd(Hncpoi)(2,2′-bpy)(H2O)]n(1),{[Cd2(Hncpoi)2(bpyp)(H2O)4]·3H2O}n(2),{[Cd2(Hncpoi)2(azpy)(H2O)2]·2H2O}n(3),{[Cd2(Hncpoi)2(dpe)(H2O)2]·2H2O}n(4),其中H3ncpoi为5-(2-硝基-4-羧基苯氧基)-间苯二甲酸,2,2′-bpy为2,2′-联吡啶,bpyp为1,4-二-吡啶基-4-亚甲基-哌嗪,azpy为4,4′-偶氮吡啶,dpe为1,2-二-(4-吡啶基)乙烯。对4个配合物进行了X射线单晶衍射、粉末衍射,元素分析、热重、荧光光谱等表征。X射线单晶结构分析表明,配合物1,2具有一维链状结构,而配合物3,4则具有二维(4,4)格子层状结构,一维链和二维层之间通过分子间作用力连接成三维超分子结构。进一步研究表明,辅助配体的构型、配位方式等对晶体结构具有决定性作用。与此同时,对几个配合物的荧光光谱进行分析,发现不同的辅助配体对配合物的荧光性能有着显著的影响。     

Syntheses,structures, and properties of CdII and CoII complexes with 5-(pyridin-4-yl)isophthalate

A N-donor containing carboxylic ligand, 5-(pyridin-4-yl)isophthalic acid (H₂L), was applied to construct two new coordination polymers [Cd(L)(DMF)] _n (1, DMF?=?N,N-dimethylformamide) and {[Co(L)(H₂O)₂]?·?0.5CH₃OH?·?1.5H₂O} _n (2) under different conditions. The complexes were characterized by IR, elemental, and thermogravimetric analyses, powder and single crystal X-ray diffraction. In 1 each L^2? links four Cd^II to form a 3-D framework, while in 2 each L^2? connects three metals to form a 2-D layer structure, which is further connected together by hydrogen bonds to form a 3-D architecture. The thermal stability of the complexes and the photoluminescence of 1 were investigated.     

Multifunctional Lanthanide‐Based Metal–Organic Frameworks with a Polyheterotopic Ligand: Doped with Ytterbium(III) for Luminescence Enhancement and Selective Dye Adsorption

The chemistry of metal–organic frameworks has been progressing fast with its exciting potential in multifunctional applications. A series of three‐dimensional lanthanide‐based metal–organic frameworks, {[Ln(HTPO)(NO₃)(H₂O)]⋅x(CH₃CN)⋅y(H₂O)}_n (Ln=Eu ( 1 ), Tb ( 2 ), Gd ( 3 ), Sm ( 4 ), Dy ( 5 ), Nd ( 6 )), {[Eu(TPO)(HCOO)_0.5]⋅(H₃O)_0.5}_n ( 7 ), {[Eu(TPO)(DMF)]⋅(solv)_x}_n ( 8 ; DMF= N,N‐dimethylformamide), and {[Eu(TPO)(DMA)]⋅(solv)_x}_n ( 9 ; DMA=dimethylacetamide) were synthesized with semirigid C₃‐symmetric ligand tris(4‐carboxylphenyl)phosphine oxide (H₃TPO). In these frameworks, the H₃TPO ligand exists in a totally different configuration. Framework 1 exhibits good breathing properties for absorbing more guest molecules through a solvent‐induced single‐crystal‐to‐single‐crystal (SC–SC) transformation involving a configuration transformation of the organic linker in the framework. The ytterbium ion was doped into 1 to improve the luminescent performance (lifetime and quantum yield) of the red europium emission. Among a series of Eu_1−xYb_xTPO samples, Eu_0.88Yb_0.12TPO showed enhanced luminescence intensity (≈5.1 times that of the pure europium system), and the lifetime increased from 1073.08 to 1236.57 μs. Moreover, the porosity of these frameworks allows them to efficiently adsorb dye molecules with high selectivity and efficiency.     

A novel two‐dimensional cadmium(II) complex: poly[diaquatris(μ4‐cyclohexane‐1,4‐dicarboxylato)bis[2‐(pyridin‐4‐yl)‐1H‐benzimidazole]tricadmium(II)

The title compound, [Cd₃(C₈H₁₀O₄)₃(C₁₂H₉N₃)₂(H₂O)₂]_n or [Cd₃(chdc)₃(4‐PyBIm)₂(H₂O)₂]_n, was synthesized hydrothermally from the reaction of Cd(CH₃COO)₂·2H₂O with 2‐(pyridin‐4‐yl)‐1H‐benzimidazole (4‐PyBIm) and cyclohexane‐1,4‐dicarboxylic acid (1,4‐chdcH₂). The asymmetric unit consists of one and a half Cd^II cations, one 4‐PyBIm ligand, one and a half 1,4‐chdc²⁻ ligands and one coordinated water molecule. The central Cd^II cation, located on an inversion centre, is coordinated by six carboxylate O atoms from six 1,4‐chdc²⁻ ligands to complete an elongated octahedral coordination geometry. The two terminal rotationally symmetric Cd^II cations each exhibits a distorted pentagonal–bipyramidal geometry, coordinated by one N atom from 4‐PyBIm, five O atoms from three 1,4‐chdc²⁻ ligands and one O atom from an aqua ligand. The 1,4‐chdc²⁻ ligands possess two conformations, i.e.e,e‐trans‐chdc²⁻ and e,a‐cis‐chdc²⁻. The cis‐1,4‐chdc²⁻ ligands bridge the Cd^II cations to form a trinuclear {Cd₃}‐based chain along the b axis, while the trans‐1,4‐chdc²⁻ ligands further link adjacent one‐dimensional chains to construct an interesting two‐dimensional network.     

Synthesis,crystal structures,and fluorescence properties of (RS)-2-methylglutarato Zn(II), Cd(II) complexes

Reactions of fresh M(OH)₂ (M = Zn²⁺, Cd²⁺) precipitate and (RS)-2-methylglutaric acid (H₂MGL), 2,2′-bipyridine (bipy), or 1,10-phenanthroline (phen) in aqueous solution at 50°C afforded four new metal–organic complexes [Zn₂(bipy)₂(H₂O)₂(MGL)₂] (1), [Zn₂(phen)₂(H₂O)(MGL)₂] (2), [Cd(bipy)(H₂O)(MGL)] · 3H₂O (3), and [Cd(phen)(H₂O)(MGL)] · 2H₂O (4), which were characterized by single crystal X-ray diffraction, IR spectra, TG/DTA analysis as well as fluorescence spectra. In 1, the [Zn(bipy)(H₂O)]²⁺ moieties are linked by R- and S-2-methylglutarate anions to build up the centrosymmetric dinuclear [Zn₂(bipy)₂(H₂O)₂(MGL)₂] molecules. In 2, the 1-D ribbon-like chains [Zn₂(phen)₂(H₂O)(MGL)₂] _n can be visualized as from centrosymmetric dinuclear [Zn₂(phen)₂(H₂O)₂(MGL)₂] units sharing common aqua ligands. Both 3 and 4 exhibit 1-D chains resulting from [Cd(bipy)(H₂O)]²⁺ and [Cd(phen)(H₂O)]²⁺, respectively, bridged alternately by R- and S-2-methylglutarate anions in bis-chelating fashion. The intermolecular and interchain π···π stacking interactions form supramolecular assemblies in 1 and 1-D chains in 2–4 into 2-D layers. The hydrogen bonded lattice H₂O molecules are sandwiched between 2-D layers in 3 and 4. Fluorescence spectra of 1–4 exhibit LLCT π → π* transitions.     

Syntheses,crystal structures,and fluorescent properties of two Cd(II) complexes based on 2,2′-(ethane-1,2-diyl)bis(1H-imidazole-4,5-dicarboxylic acid)

Two new complexes, [Cd₂(H₄ebidc)₂(CH₃OH)₄]?·?2CH₃OH (1) and {[Cd(Cl)(I)(H₆ebidc)_1/2]?·?1/2bbe?·?H₂O} _n (2) (H₆ebidc?=?2,2′-(ethane-1,2-diyl)bis(1H-imidazole-4,5-dicarboxylic acid), bbe?=?1,2-bis(2-benzimidazolyl)ethane), are obtained through self-assembly of H₆ebidc with Cd(II). Single-crystal X-ray diffraction shows that 1 has a binuclear structure and each tridentate chelating ligand coordinates to two Cd(II) ions with µ₂-O. Complex 2 displays a 1-D chain structure and each tetradentate ligand bridges two Cd(II) ions in chelating fashion. Fluorescent properties have also been determined.     

Cu(II)/Cd(II) coordination polymers based on polycarboxylate and 2-(2-pyridyl)benzimidazole

Three polycarboxylate coordination polymers containing 2-(2-pyridyl)benzimidazole as co-ligand, [Cu(Bdc)(2-PyBIm)] _n (1), [Cu(HBtc)(2-PyBIm)] _n (2) and [Cd₂(HBtc)₂(2-PyBIm)₂] _n ·; nH₂O (3) (H₂Bdc?=?1,4-benzenedicarboxylic acid; H₃Btc?=?1,3,5-benzenetricarboxylic acid), have been synthesized and characterized by elemental analyses, IR spectra, TG-DSC and X-ray structural analyses. Complex 1 is a one-dimensional zigzag chain in which the Cu(II) is cis six-coordinated by two chelating carboxyl groups and a 2-PyBIm ligand. Complex 2 is a two-dimensional (4, 4) network in which H₃Btc is partially deprotonated. Complex 3 has a three-dimensional framework in which one Cd(II) is six-coordinate and the other is seven-coordinate. All 2-PyBIm groups are neutral, chelating, bidentate ligands in 1–3. These complexes are quite thermally stable. The luminescence of 3 has also been investigated.     

基于5,5’-亚甲基二间苯二甲酸及1,2-双（咪唑基-1-甲基）-苯的Zn2+、Co2+配位聚合物的合成及晶体结构

水热条件下,合成了2个三维配位聚合物{[Zn₄（L）₂（o-bix）₂]·2H₂O}_n（1）,{[Co₄（L）₂（o-bix）₂]·2H₂O}_n（2）（H₄L=5,5’-亚甲基二间苯二甲酸,o-bix=1,2-双（咪唑基-1-甲基）-苯）,并通过红外、热重和X-射线单晶衍射进行了表征。X-射线衍射结果表明这2个化合物具有相似的结构。在1个不对称单元中,化合物包含2个不同配位环境的金属离子,1个L^4-配体,1个o-bix分子以及1个游离的溶剂水分子。中心金属离子分别采用畸变的四面体和四方锥构型,形成两类双核单元,然后通过全部脱质子的L^4-形成3D孔洞结构,o-bix配体通过连接两类双核金属原子填充于孔洞之中,形成3D紧密堆积结构。对化合物的红外和热重性质进行了表征。     

Two new metal-organic frameworks possessing binodal high-connected topologies based on Cd4-clusters and organic ligands

Two new compounds, [Cd₂(bptc)(bpimb)(H₂O)]?·?2H₂O (1) and [Cd₂(bptc)(bpib)]?·?4H₂O (2) (where H₄bptc?=?biphenyl-3,3′,4,4′-tetracarboxylic acid, bpimb?=?1,3-bis((2-(pyridin-2-yl)-1H-imidazol-1-yl)methyl)benzene, bpib?=?1,4-bis(2-(pyridin-2-yl)-1H-imidazol-1-yl)butane), were synthesized by reactions of the corresponding metal salts with H₄bptc and N-containing auxiliary ligands and their structures have been determined by single-crystal X-ray diffraction. Compound 1 is built by Cd₄-clusters which further construct a 3-D (3,8)-connected framework with tfz-d notation; 2, also built by Cd₄-clusters, is a 3-D (4,8)-connected framework with (3²?·?4²?·?5²)(3⁴?·?4⁸?·?5¹²?·?6⁴) topology. In addition, the elemental analyses, infrared spectra, fluorescence, and thermogravimetric analyses for 1 and 2 are discussed.     

Crystal Structures and Luminescence of Two Cadmium‐Carboxylate Cluster‐based Compounds with Mixed Ligands

Reactions of Cd(NO₃)₂ · 4H₂O with 2‐quinolinecarboxylic acid (H‐QLC) in the presence of 1,4‐benzenedicarboxylic acid (H₂‐BDC) or 1,3,5‐benzenetricarboxylic acid (H‐BTC) in DMF/H₂O solvent afforded two compounds, namely, [Cd(QLC)(BDC)_1/2(H₂O)]_n ( 1 ) and [Cd(QLC)(BTC)_1/3]_n ( 2 ). Both compounds are two‐dimensional (2D) frameworks but feature different cadmium‐carboxylate clusters as a result of the presence of the polycarboxylate ligands with different geometries and coordination preference. The dinuclear Cd₂(QLC)₂ units in 1 are bridged by the pairs of bridging water ligands to give a one‐dimensional (1D) chain, which is further linked by the second ligand of BDC^2– to form a 2D structure. Compound 2 is constructed from unique hexanuclear macrometallacyclic Cd₆(QLC)₆ clusters, which are linked by the surrounding BTC^3– ligands to generate a 2D structure. Photoluminescence studies showed both compounds exhibit ligand‐centered luminescent emissions with emission maxima at 405 and 401 nm, respectively.     

Syntheses,crystal structures,and photoluminescent properties of two new Cd(II) coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate and dipyridyl-containing ligands

Two new Cd(II) coordination polymers, [Cd₂(btc)(dpe)_1.5(H₂O)]_n (1) and [Cd₂(btc)(bpp)(H₂O)]_n (2), were prepared by the hydrothermal reaction of cadmium nitrate with H₄btc (H₄btc = biphenyl-2,2′,4,4′-tetracarboxylic acid) in the presence of 1,2-di(4-pyridyl)ethylene (dpe) and = 1,2-bis(4-pyridyl)propane (bpp), respectively, structurally characterized by single-crystal X-ray diffraction, and further characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. In 1, btc^4? connect six Cd²⁺ ions, forming a 3-D (3,3,6)-connected [Cd₂(btc)] net, and further connected by 1-D [Cd(dpe)]_n chains to construct the final (4,5,6)-connected (4².5².6⁵.7)(4³.6².7)(4⁵.5³.6⁴.7².8) net. In 2, a 3-D [Cd₂(btc)] net is also constructed from btc^4? connecting six Cd²⁺ ions, giving a 3-D (3,4,7)-connected network. The overall structure of 2 can be regarded as a (4,4,6)-connected (4⁵.6⁴) (4².5.6².8) (4³.5⁴.6⁷.7) framework with bpp linking adjacent Cd ions. Structural comparisons show that the secondary auxiliary N-donors have important effects on the final structure and properties. Photoluminescent properties of 1 and 2 are also discussed.