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1.
A new family of framework nanostructures including carbon atoms in sp 2 and sp 3 hybridized states is reported. Structure optimization was fulfilled using MM+ molecular mechanics and Hückel semiempirical methods. The energy characteristics of the structures have been evaluated. Comparative analysis of the stability of the title nanostructures has been performed in relation to their geometry and relative contents of sp 2/sp 3 atoms.  相似文献   

2.
总结了近年来在水溶性三维超分子聚合物、 超分子有机框架、 超分子-金属有机框架杂化结构、 超分子-共价-金属有机框架杂化结构及共价有机框架合成、 催化和输送功能方面的研究进展, 指出了有序三维聚合物未来研究面临的挑战并展望今后的发展方向.  相似文献   

3.
Eight isomorphous metal‐organic frameworks: [Ln2(TATAB)2(H2O)(DMA)6]·5H2O (Ln = Sm ( 1 ), Eu ( 2 ), Gd ( 3 ), Tb ( 4 ), Dy ( 5 ), Er ( 6 ), Tm ( 7 ), Yb ( 8 )); TATAB = 4,4′,4″‐s‐triazine‐1,3,5‐triyl‐p‐aminobenzoate, DMA = N,N‐dimethylacetamide), were synthesized by the self‐assembly of lanthanide ions, TATAB, DMA and H2O. Single‐crystal X‐ray crystallography reveals they are three dimensional frameworks with 2‐fold interpenetration. Solid‐state photoluminescence studies indicate ligand‐to‐metal energy transfer is more efficient for compounds 2 and 4 which exhibit intense characteristic lanthanide emissions at room temperature.  相似文献   

4.
Porous metal‐organic frameworks (MOFs) loading metal nanoparticles to form a composite photocatalyst demonstrated unique advantages. Modification of the electron donating group on the aromatic linkers of MOFs could increase the absorption range of light, thereby increasing the photocatalytic activity. In this study, we prepared a composite photocatalyst using a stable NH2‐functionalized MOF (UiO‐66‐NH2) to load semiconductor Ag/AgBr nanoparticles, and the resultant composites have intense optical absorption throughout visible light range. The greatly enhanced optical absorption and the unique hetero‐junction between Ag/AgBr and UiO‐66‐NH2 render efficient separation and utilization of photogenerated electron‐hole pairs. Therefore, Ag/AgBr@UiO‐66‐NH2 showed much more excellent photocatalytic activity, compared with unmodified UiO‐66 loading Ag/AgBr (Ag/AgBr@UiO‐66) and reported AgX@MOF catalysts. Moreover, the composite photocatalysts showed excellent stability during cycling experiment.  相似文献   

5.
The construction of diverse sp3‐rich skeletal ring systems is of importance to drug discovery programmes and natural product synthesis. Herein, we report the photocatalytic construction of 2,7‐diazabicyclo[3.2.1]octanes (bridged 1,3‐diazepanes) via a reductive diversion of the Minisci reaction. The fused tricyclic product is proposed to form via radical addition to the C4 position of 4‐substituted quinoline substrates, with subsequent Hantzsch ester‐promoted reduction to a dihydropyridine intermediate which undergoes in situ two‐electron ring closure to form the bridged diazepane architecture. A wide scope of N‐arylimine and quinoline derivatives was demonstrated and good efficiency was observed in the construction of sterically congested all‐carbon quaternary centers. Computational and experimental mechanistic studies provided insights into the reaction mechanism and observed regioselectivity/diastereoselectivity.  相似文献   

6.
The La(III) complex with a new amide‐type tripodal ligand,2,2′.2″‐nitrilotris{[(2′‐benzylaminofomyl)‐phenoxylethyl)amine (L), was synthesized and characterized by X‐ray crystallographic analysis. Crystal data: C48H55.50LaN7O18.75, Mr=1169.40, monoclinic. space group, P21/n, a= 1.0644(3) nm. b=2.3889(5) nm, c= 2.1917(5) nm, β=90.65°, V=5.573(2) nm3, Z=1, Dc=1.394 g°cm?3, R1=0.0487, wR [1>2s?(I)]=0.1266. The results reveal that each La(III) ion binds to 9 oxygen atoms, three of which belong to carbonyl groups from three tripodal ligands and six to three bidentate nitrate groups and a two‐dimensional sheet of 4.82 networks is assembled by metal‐ligand coordination interaction. L, a heptadentate compound, merely acts as a tridentate bridging spacer due to its steric hindrance and links the La(III) ions as three‐connected nodes.  相似文献   

7.
The reaction of ZnII nitrate with maleic acid (H2mal) / fumaric acid (H2fum) and 4,4′‐dipyridyl disulfide (4‐pds) resulted under same conditions in two distinct interpenetrated compounds, namely [Zn(4‐dps)2(H2O)2]·2Hmal ( 1 ) and [Zn(4‐dps)(fum)] ( 2 ). In 1 , Hmal anion adopts bridging mode based on hydrogen bonding, affording a 2‐fold parallel interpenetrated 3D→3D α‐Po net hydrogen‐bonded framework, in which 1D double‐stranded chains are formed, and then extended to a 3D supramolecular architecture combining second‐sphere hydrogen‐bonded interactions. For 2 , fum dianion takes on bis‐dentate bridging coordination fashion, furnishing a 2‐fold interpenetrated 2D→2D (4,4) layered coordination network, in which the tetrahedral ZnII atoms are interlinked by 4‐dps and fum. Additionally, the compound 2 shows strong fluorescence in the solid state at room temperature.  相似文献   

8.
Polycationic Hg‐Pnictide Frameworks with a Novel Kind of Filling in the Structures of Hg3As2TlCl3 and Hg3Sb2TlBr3 Hg3As2TlCl3 and Hg3Sb2TlBr3 were prepared from mixtures of Hg2X2, HgX2 (X = Cl, Br), As or Sb and Tl in sealed evacuated glass ampoules in temperature gradients 330 °C → 290 °C for Hg3As2TlCl3 (red, transparent crystals) and 290 °C → 260 °C for Hg3Sb2TlBr3 (black crystals). The structures of the diamagnetic compounds were determined based on single crystal X‐ray diffraction data. Both compounds crystallize isotypically in the orthorhombic space group Pbcm with Z = 4 and the lattice constants a = 629.2(5) pm, b = 1234.1(7) pm and c = 1224.8(9) pm for Hg3As2TlCl3 and a = 661.0(4) pm, b = 1311.2(9) pm and c = 1307.1(2) pm for Hg3Sb2TlBr3. The structures can be described either as a cubic closest packing of As2/Sb2 dumb‐bells and halide anions with all octahedral interstices filled with Hg2+ and Tl+, or as a polycationic framework (Hg3Y2)2+ (Y = As, Sb) consisting of pnictide‐pnictide dumbbells each connected by six Hg atoms to a three dimensional porous arrangement. The centers of the cavities are occupied by Tl+ ions which are coordinated by six halide ions in distorted octahedral form. These TlX6 octahedra share corners in all directions in the motive of the ReO3 structure type. This new structure type shows a close relationship to the cubic family of compounds of the general formula (Hg6Y4)[MX6]X (Y = As, Sb; M = Mo, Ti, Bi, Sb; X = Cl, Br). The halide ions are connected to the Hg atoms of the polycationic network and to the Tl+ ions. Extended Hueckel calculations were used to explain the bonding character of the thallium–halide and mercury–halide bonds.  相似文献   

9.
High‐pressure single‐crystal X‐ray diffraction has been used to trap both the low‐spin (LS) and high‐spin (HS) states of the iron(II) Hofmann spin crossover framework, [FeII(pdm)(H2O)[Ag(CN)2]2?H2O, under identical experimental conditions, allowing the structural changes arising from the spin‐transition to be deconvoluted from previously reported thermal effects.  相似文献   

10.
《Electroanalysis》2018,30(3):474-478
A non‐enzymatic electrochemical glucose sensor based on a Cu‐based metal‐organic framework (Cu‐MOF) modified electrode was developed. The Cu‐MOF was prepared by a simple ionothermal synthesis, and the characterizations of the Cu‐MOF were studied by Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), single‐crystal X‐ray powder diffraction (SCXRD), and X‐ray powder diffraction (XRD). Electrochemical behaviors of the Cu‐MOF modified electrode to glucose were measured by differential pulse voltammetry (DPV). The electrochemical results showed that the Cu‐MOF modified electrode exhibited an excellent electro‐catalytic oxidation towards glucose in the range of 0.06 μM to 5 mM with a sensitivity of 89 μA/mM cm2 and a detection limit of 10.5 nM. Moreover, the fabricated sensor showed a high selectivity to the oxidation of glucose in coexistence with other interferences. The sensor was satisfactorily applied to the determination of glucose in urine samples. With the significant electrochemical performances, MOFs may provide a suitable platform in the construction of kinds of electrochemical sensors and/or biosensors and hold a great promise for sensing applications.  相似文献   

11.
A terbium–organic framework (Tb‐MOF) was prepared using a previously reported procedure. Tb‐MOF was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, powder X‐ray diffraction and surface area analysis. Tb‐MOF was employed as a heterogeneous Lewis acid catalyst for the synthesis of β‐aminoalcohols. Also, the effect of ultrasonic irradiation was examined in the catalytic aminolysis of styrene oxide. The reaction conditions were optimized by variation of reaction time, catalyst concentration and solvent. A variety of β‐aminoalcohols were synthesized and characterized. The Tb‐MOF catalyst showed excellent selectivity and high yield for these transformations.  相似文献   

12.
The open‐framework iron phosphate Fe2lllFe1.5ll,(PO4)3 was hydrothermally synthesized and characterized by elemental analysis, IR, EPR, XPS and single crystal X‐ray diffraction analysis. The title compound crystallized in the triclinic, space group P1 with a=0.64724(4) nm, b=0.79651(6) nm, c=0.94229(5) nm, a= 104.447(2)°. β= 108.919(4)°. y= 101.741(4)°, V=0.42302(5) nm3, Z= 1 and RI (wR2)=0.0307 (0.0793). Crystal data were collected on a Rigaku R‐AXIS RAPID IP diffractometer with Mo Ka (γ=0.071073 nm) at 293(2) K in the range of 2.43°<Õ <27.46°. The structure of 1 consists of 19 non‐hydrogen atoms including three and a half crystallographically independent Fe and three P atoms. Fe(1) connects its symmetrical Fe(1A) through bridging oxygen forming a dimer and the dimers are connected by Fe(4) forming an infinite staircase‐like chain. Fe(2) and Fe(3) connect the infinite chains into a layer with bridging oxygen. Layers are interconnected via Fe(4) forming the six‐membered and eight‐membered channel systems.  相似文献   

13.
14.
The reaction of CuBr2, N(CH2CH2COOH)3, and Nd(NO3)3·6H2O in water adjusted pH = 5‐6 with H2SO4 at constant 55 °C afforded a novel three‐dimensional coordination complex [Cu12(SO4)12(3H2O)]·H2O, ( 1 ), which was characterized by IR, elemental analysis, and X‐ray diffraction. The crystal structure data of 1 as follows: Cubic, , a = b = c = 24.018(2) Å, V = 13855 (3) Å3, Z = 968, Dc = 1.905 g/cm3, F(000) = 7712, R1 = 0.0352, wR2 = 0.0866 (I > 2σ(I)), R1 = 0.0449, wR2 = 0.0927 (for all data) and S = 1.075. The analysis of crystal structure indicates that the structure of 1 is similar to that of silicate zeolite (Na12[Al12Si12O48]·27H2O).  相似文献   

15.
The Group 18 elements (noble gases) were the last ones in the periodic system to have not been encountered in perovskite structures. We herein report the synthesis of a new group of double perovskites KM(XeNaO6) (M=Ca, Sr, Ba) containing framework‐forming xenon. The structures of the new compounds, like other double perovskites, are built up of the alternating sequence of corner‐sharing (XeO6) and (NaO6) octahedra arranged in a three‐dimensional rocksalt order. The fact that xenon can be incorporated into the perovskite structure provides new insights into the problem of Xe depletion in the atmosphere. Since octahedrally coordinated XeVIII and SiIV exhibit close values of ionic radii (0.48 and 0.40 Å, respectively), one could assume that XeVIII can be incorporated into hyperbaric frameworks such as MgSiO3 perovskite. The ability of Xe to form stable inorganic frameworks can further extend the rich and still enigmatic chemistry of this noble gas.  相似文献   

16.
In the present study, the synthesis of mordenite zeolite/MIL‐101(Cr) metal–organic framework (MOF) composite [MOR/MIL‐101(Cr)] using the ship in a bottle method was suggested. The properties of prepared composite and individual MOF and MOR zeolite were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption measurement, and thermogravimetric analysis (TGA). The XRD results indicated diffraction peaks for each compound (MOR and MOF) in composite. The SEM and TEM images showed the formation of plates MOR (with size of 2.5 × 3 μm) along with spherical particles MIL‐101. The Brunauer–Emmett–Teller results showed that the surface area of the composite was smaller than individual MOF and MOR zeolite. Based on TGA plots, the hybrid zeolite/MOF composite was more thermally stable compared with the isolated MIL‐101(Cr). The composite was functionalized by post‐synthetic modification to obtain acid–base bifunctionality (H‐MOR/MIL‐101‐ED) for the synthesis of chromene derivatives. The acidity from framework Al‐O(H)‐Si sites in MOR and basicity from amine groups in MIL‐101 were obtained by post‐synthetic modification.  相似文献   

17.
The 2D CuII metal‐organic framework [Cu2(bptc)(H2O)4]n · 4nH2O ( 1 ) (H4bptc = biphenyl‐2,2′,4,4′‐tetracarboxylic acid) was hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction and magnetic measurements. In the structure, bptc4– serves as a twisted Π‐shaped organic building block to connect paddlewheel [Cu2(COO)4] dinuclear units and mononuclear units through 2‐/2′‐carboxylate and 4‐/4′‐carboxylate, respectively. According to the magnetic analysis using a dimer‐plus‐monomer model, strong antiferromagnetic coupling is operative within the dinuclear unit (J = –311 cm–1 based on H = –J S 1 S 2), and the compound behaves like a mononuclear molecule at low temperature.  相似文献   

18.
For the first time, metal‐exchange in a magnetic metal–organic framework (MOF) via tandem magnetization and post‐synthetic modification has been developed. The new magnetic mixed‐metal metal–organic framework nanocomposite, CoFe2O4/[Cu0.63/Zn0.37‐TMU‐17‐NH2] (CoFe2O4/[Cu/Zn‐MOF]) has been synthesized by immersing the CoFe2O4/Zn‐TMU‐17‐NH2 (CoFe2O4/Zn‐MOF) as a template in DMF solution of Cu (II) salts. CoFe2O4/[Cu/Zn‐MOF] showed to be a highly reactive and easily recoverable magnetic catalyst for the preparation of tetrazole derivatives via one‐pot three‐component reactions of different aldehydes with hydroxyl amine hydrochloride and sodium azide. Our results (Fourier transform‐infrared, inductively coupled plasma‐optical emission spectroscopy, powder X‐ray diffraction, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy‐mapping and vibrating‐sample magnetometer) show successful partial metal‐exchange in which the framework integrity remained intact during the metal‐exchange process.  相似文献   

19.
A novel 3‐connected SrSi2‐type 3D chiral framework constructed from hexa‐NiII‐cluster‐substituted polyoxometalate (POM) units [Ni(enMe)2]3[WO4]3[Ni6(enMe)3(OH)3PW9O34]2?9H2O ( 1 ) (enMe=1,2‐diaminopropane) has been made from a hydrothermal synthetic method. This POM represents the first 3D framework based on {Ni6PW9} units and {WO4} connectors.  相似文献   

20.
Synthesizing energetic metal–organic frameworks at ambient temperature and pressure has been always a challenge in the research area of energetic materials. In this work, through in situ controllable synthesis, energetic metal–organic framework gem‐dinitromethyl‐substituted dipotassium 4,5‐bis(dinitromethyl)‐1,2,3‐triazole with a “cage‐like” crystal packing was obtained and characterized. Most importantly, for the first time, we found that it could be successfully afforded with a catalytic effect of trifluoroacetic acid. This new compound exhibited its high density (2.04 g cm?3) at ambient temperature, superior detonation velocity (8715 m s?1) to that of lead azide (5877 m s?1) and comparable to that of RDX (8748 m s?1). Its detonation products are mainly N2 (48.1 %), suggesting it is also a green energetic material. The above‐mentioned performance indicates its potential applications in detonator devices as lead‐free primary explosive.  相似文献   

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