基于氨三乙酸和钕的三维金属有机框架物的合成及结构表征(英文)

利用水热法合成了三维网状金属有机框架物[Nd(NTA)(H2O)]∞[其中NTA指氨三乙酸根(nitrilotriacetate anion)];采用元素分析仪、红外光谱仪和X射线单晶衍射仪等分析了产物的组成以及化学结构和晶体结构。结果表明,目标配合物中的NTA为四齿配体,Nd(III)原子采取八配位模式(NdN1O7)形成十二面体立体结构。与此同时,[Nd(NTA)(H2O)]∞以菱形四面体Nd8C14O28为构筑块,通过桥连羧基和分子间氢键组装成为三维超分子网络结构。     

A designed metal-organic framework based on a metal-organic polyhedron

A C(3) symmetric ligand with three 1,3-benzenedicarboxylate units has been used to construct a metal-organic framework with a (3,24)-connected network topology, where the nanometre-sized metal-organic cuboctahedra (MOCs) have been incorporated solely into a cubic close packing (CCP) arrangement, which led to superoctahedral and supertetrahedral cavities.     

Direct synthesis of bifunctional periodic mesoporous benzene-silicas functionalized with a high loading of carboxylic acid groups

Well-ordered periodic mesoporous benzene-silicas functionalized with a high loading of pendant carboxylic acid groups (up to 60 mol% based on silica) have been successfully synthesized via co-condensation of 1,4-bis(triethoxysilyl)benzene and carboxyethylsilanetriol sodium salt using Pluronic P123 as a template and KCl as an additive.     

Construction of a magnetic chiral coordination polymer based on a semi-rigid carboxylic acid

A 2-D chiral entangled coordination polymer, {Mn₃(2,2′-bpy)₂(3-cpta)₂·H₂O}_n (1) (3-H₃cpta=3-(3′-carboxyphenoxy)phthalic acid, 2,2′-bpy=2,2′-bipyridine), has been synthesized via the solvothermal method. X-ray diffraction analysis reveals that 1 consists of one right-handed helical chain and one wavelike 2-D plane, which are connected with each other through hydrogen bonds and π···π interactions to generate a 3-D supra-molecule. Thermal gravimetric analysis shows that 1 possesses good thermal stability. Temperature dependent magnetic susceptibilities have also been measured from 1.8 to 300 K, which shows 1 to be anti-ferromagnetic.     

Thermal transformation of a layered multifunctional network into a metal-organic framework based on a polymeric organic linker

The preparation of layered [La(H(3)nmp)] as microcrystalline powders from optimized microwave-assisted synthesis or dynamic hydrothermal synthesis (i.e., with constant rotation of the autoclaves) from the reaction of nitrilotris(methylenephosphonic acid) (H(6)nmp) with LaCl(3)·7H(2)O is reported. Thermogravimetry in conjunction with thermodiffractometry showed that the material undergoes a microcrystal-to-microcrystal phase transformation above 300 °C, being transformed into either a three-dimensional or a two-dimensional network (two models are proposed based on dislocation of molecular units) formulated as [La(L)] (where L(3-) = [-(PO(3)CH(2))(2)(NH)(CH(2)PO(2))O(1/2)-](n)(3n-)). The two crystal structures were solved from ab initio methods based on powder X-ray diffraction data in conjunction with structural information derived from (13)C and (31)P solid-state NMR, electron microscopy (SEM and EDS mapping), FT-IR spectroscopy, thermodiffractometry, and photoluminescence studies. It is shown that upon heating the coordinated H(3)nmp(3-) anionic organic ligand undergoes a polymerization (condensation) reaction to form in situ a novel and unprecedented one-dimensional polymeric organic ligand. The lanthanum oxide layers act, thus, simultaneously as insulating and templating two-dimensional scaffolds. A rationalization of the various steps involved in these transformations is provided for the two models. Photoluminescent materials, isotypical with both the as-prepared ([(La(0.95)Eu(0.05))(H(3)nmp)] and [(La(0.95)Tb(0.05))(H(3)nmp)]) and the calcined ([(La(0.95)Eu(0.05))(L)]) compounds and containing stoichiometric amounts of optically active lanthanide centers, have been prepared and their photoluminescent properties studied in detail. The lifetimes of Eu(3+) vary between 2.04 ± 0.01 and 2.31 ± 0.01 ms (considering both ambient and low-temperature studies). [La(H(3)nmp)] is shown to be an effective heterogeneous catalyst in the ring opening of styrene oxide with methanol or ethanol, producing 2-methoxy-2-phenylethanol or 2-ethoxy-2-phenylethanol, respectively, in quantitative yields in the temperature range 40-70 °C. The material exhibits excellent regioselectivity to the β-alkoxy alcohol products even in the presence of water. Catalyst recycling and leaching tests performed for [La(H(3)nmp)] confirm the heterogeneous nature of the catalytic reaction. Catalytic activity may be attributed to structural defect sites. This assumption is somewhat supported by the much higher catalytic activity of [La(L)] in comparison to [La(H(3)nmp)].     

A penetrating metal-organic framework based on N-heterocyclic carboxylic acid with sensing properties toward Cr(VI)/Fe(III) and nitrobenzene

Abstract

A luminescent metal-organic framework, [Cd(tmlb)(bbibp)]_n (1) (H₂tmlb?=?(1H-1,2,4-triazol-1-yl)methylenebis(benzonic acid), bbibp?=?bis(benzoimidazo-1-ly)biphenyl), has been solvothermally synthesized and characterized by elemental analysis, infra-red spectroscopy, single-crystal X-ray diffraction, thermogravimetric analysis, and powder X-ray diffraction. Complex 1 exhibits two interpenetrating uninodal 4-connected 3-D frameworks with a (6⁵·8) topology. The luminescence studies reveal that the complex displays sensitive and selective luminescence sensing toward Cr(VI) (CrO₄^2? and Cr₂O₇^2?) anions, Fe(III) cation, and nitrobenzene. The potential quench mechanism was discussed.     

Assembly of hydrogen bonded diamondoid networks based on synthetic metal-organic tetrahedral nodes

Reaction of Mn(ClO4)2 or Co(PF6)2 with 4,4'-dipyridine-dioxide (dpdo) produced novel molecular species [M(dpdo)4(H2O)2]2+, which hold a tetrahedral configuration notwithstanding their octahedral environment around the metal centers. The tetrahedral moieties are further assembled through hydrogen bonds between peripheral NO ends of dpdo ligands and coordinated water molecules, giving rise to 3D diamondoid networks.     

Luminescent and magnetic bifunctional coordination complex based on a chiral tartaric acid derivative and europium

A new mononuclear europium complex incorporating the (+)‐di‐p‐toluoyl‐d ‐tartaric acid (d ‐H₂DTTA) ligand, namely, catena‐poly[tris{μ₂‐3‐carboxy‐2,3‐bis[(4‐methylphenyl)carbonyloxy]propanoato}tris(methanol)europium(III)], [Eu(C₂₀H₁₇O₈)₃(CH₃OH)₃]_n, (I), has been synthesized and characterized by IR spectroscopy, elemental analysis, powder X‐ray diffraction and single‐crystal X‐ray diffraction analysis. The structure analysis indicates that complex (I) crystallizes in the trigonal space group R3 and exhibits an infinite one‐dimensional chain structure, in which the Eu³⁺ ion is surrounded by six O atoms from six d ‐HDTTA^? ligands and three O atoms from three coordinated methanol molecules, thus forming a tricapped trigonal prism geometry. The d ‐H₂DTTA ligand is partially deprotonated and adopts a μ_1,6‐coordination mode via two carboxylate groups to link adjacent Eu³⁺ ions, affording an infinite one‐dimensional propeller‐shaped coordination polymer chain along the c axis, with an Eu…Eu distance of 7.622 (1) Å. Moreover, C—H…π interactions lead to the formation of helical chains running along the c axis and the whole structure displays a snowflake pattern in the ab plane. The circular dichroism spectrum confirms the chirality of complex (I). The solid‐state photoluminescence properties were also investigated at room temperature and (I) exhibits characteristic red emission bands derived from the Eu³⁺ ion (CIE 0.63, 0.32), with a reasonably long lifetime of 0.394 ms, indicating effective energy transfer from the ligand to the metal centre. In addition, a magnetic investigation reveals single‐ion magnetic behaviour. The spin‐orbit coupling parameter (λ) between the ground and excited states is fitted to be 360 (2) cm^?1 through Zeeman perturbation. Therefore, complex (I) may be regarded as a chiral optical‐magneto bifunctional material.     

Novel photocatalysts for the decomposition of organic dyes based on metal-organic framework compounds

Three novel metal-organic frameworks (MOFs) [Co(2)(C(10)H(8)N(2))][C(12)H(8)O(COO)(2)](2), 1, [Ni(2)(C(10)H(8)N(2))(2)][C(12)H(8)O(COO)(2)](2).H(2)O, 2, and [Zn(2)(C(10)H(8)N(2))][C(12)H(8)O(COO)(2)](2), 3, with three-dimensional structures have been synthesized and characterized. The structures of the three compounds appear somewhat related, formed by the connectivity involving the metal polyhedra (Co(4)N trigonal bipyramids in 1, NiO(4)N(2) octahedra in 2, and ZnO(4) tetrahedra and ZnO(3)N(2) trigonal bipyramids in 3), 4,4'-oxybis(benzoate), and 4,4'-bipyridine. The photocatalytic studies on 1-3 indicate that they are active catalysts for the degradation of orange G, rhodamine B, Remazol Brilliant Blue R and methylene blue. The compounds have also been characterized by powder X-ray diffraction, IR, thermogravitmetric analysis, UV-vis, photoluminescence, and magnetic studies.     

Synthesis and properties of aromatic polyamides based on a benzonorbornane bis(ether carboxylic acid)

A set of new aromatic polyamides containing ether and benzonorbornane units were synthesized by the direct phosphorylation polycondensation of 3,6‐bis(4‐carboxyphenoxy)benzonorbornane with various aromatic diamines. The polymers were produced in high yields and moderate to high inherent viscosities (0.64–1.70 dL/g). The polyamides derived from rigid diamines such as p‐phenylenediamine and benzidine were semicrystalline and insoluble in organic solvents. The other polyamides were amorphous and organosoluble and afforded flexible and tough films via solution casting. These films exhibited good mechanical properties, with tensile strengths of 95–101 MPa, elongations at break of 13–25%, and initial moduli of 1.97–2.33 GPa. The amorphous polyamides showed glass‐transition temperatures between 176 and 212 °C (by differential scanning calorimetry) and softening temperatures between 194 and 213 °C (by thermomechanical analysis). Most of the polymers did not show significant weight loss before 450 °C in nitrogen or in air. Some properties of these polyamides were also compared with those of homologous counterparts without the pendent norbornane groups. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 947–957, 2002     

Postsynthetic modification at orthogonal reactive sites on mixed, bifunctional metal-organic frameworks

A series of mixed, bifunctional metal-organic frameworks were synthesized and subsequent postsynthetic modification was demonstrated on the two, orthogonal functional sites. The use of differentially 'tagged' ligands combined with postsynthetic modification provides a facile route to a large number of functionally diverse materials.     

Stepwise assembly of metal-organic framework based on a metal-organic polyhedron precursor for drug delivery

A 12-connected network with fcu topology was firstly reported focusing on using predesigned metal-organic polyhedron (MOP) as the precursor, and its adsorption and delivery of the drug 5-fluorouracil (5-FU) was also determined.     

Application of ultrasound to organic reactions: ultrasonic catalysis on hydrolysis of carboxylic acid esters

Irradiation with ultrasound was found to facilitate the two-phase basic hydrolysis of aromatic carboxylic acid esters.     

A series of pillar-layer metal-organic frameworks based on 5-aminoisophthalic acid and 4,4'-bipyridine

Four new compounds, [Cd(5-aip)(bpy)]·1.5DMA (1), [Cu(5-aip)(bpy)]·1.3DMA (2), [Co(5-aip)(bpy)]·1.6DMA (3), and [Cd(5-aip)(bpy)(0.5)(H(2)O)]·1.3DMA (4), based on 5-aminoisophthalic acid and 4,4'-bipyridine, have been synthesized by the solvothermal method and structurally determined using single crystal X-ray diffraction. Compounds 1-3 are structurally similar and show non-interpenetrating three-dimensional (3D) pillar-layer frameworks, while compound 4 displays a two-dimensional (2D) (3,4)-connected parallel non-interpenetrating architecture. In all these compounds, 1D rectangular channels are observed and the ligand 5-aminoisophthalic acid exhibits three kinds of coordination modes. Furthermore, 1 displays a single-crystal-to-single-crystal transformation when immersed in a methanol solution. More significantly, 1 can absorb and deliver I(2) molecules by means of its channels, and could induce a reversible luminescent transformation from quenching to the initial state. The luminescent properties of 1 and 4 have also been studied.     

Three-dimensional hybrid networks based on aspartic acid

Three-dimensional achiral coordination polymers of the general formula M₂(D, l-NHCH (COO)CH₂COO)₂·C₄H₄N₂ where M = Ni and Co and pyrazine acts as the linker molecule have been prepared under hydrothermal conditions starting with [M(L-NHCH(COO)CH₂COO)·3H₂O] possessing a helical chain structure. A three-dimensional hybrid compound of the formula Pb_2.5[N{CH(COO) CH₂COO}₂2H₂O] has also been prepared hydrothermally starting with aspartic acid and Pb(NO₃)₂. In this lead compound, where a secondary amine formed by the dimerisation of aspartic acid acts as the ligand, there is two-dimensional inorganic connectivity and one-dimensional organic connectivity.     

Synthesis of bifunctional chelating agents based on mono and diphosphonic derivatives of diethylenetriaminepentaacetic acid

Bifunctional chelating agents (BFCAs) are small molecules containing a chelating unit, able to strongly coordinate a metal ion, and a reactive functional group, devised to form a stable covalent bond with another molecule. BFCAs are widely employed since their conjugation to a suitable biomolecule (e.g., a peptide or an antibody) allows the synthesis of diagnostic or therapeutic agents that specifically target diseased tissue with metals or radiometals. For this reason, BFCAs find application in diagnostic imaging, molecular imaging, and radiotherapy of cancer. The synthesis of new BFCAs based on a diethylenetriaminepentaacetic acid (DTPA) structure in which one or two carboxylic groups are replaced with phosphonic units is described. The phosphonic group, aside from being a classical isostere of the carboxylic acid in coordination chemistry, allows to modulate the physico-chemical properties of the ligands and of the corresponding complexes.