Search

Suitable chemical components in water systems for human health are a crucial prerequisite for mankind's survival. Simple and effective innovations are being developed to efficiently monitor healthy and toxic substances. Here, with a hydrothermal technique, a novel thermostable metal–organic framework (MOF) [Cd2(L)(bib)0.5(H2O)3]n·1.75n(H2O) (MOF-1, H4L = biphenyl-2,3,3′,5′-tetracarboxylic acid, bib = 1,4-bis(imidazolyl)butane) was designed and synthesized. MOF-1 shows a 4,5-connection binodal 3D fsx-type topological net with irregular cages, which the bulk materials show high phase purity, excellent thermo/aqua-stability and intense fluorescence. The luminescent MOF was studied for the highly sensitive detection of trace amounts of Fe3+ ions and nitrobenzene and shows high KSV values of 4.653 × 104 and 5.724 × 104, respectively. It was also demonstrated that MOF-1 possesses superior probing ability towards nine other nitroaromatic explosives with remarkable quenching percentages. These results offer a new possibility for the potential multiple recognition of various chemical substances in human body and water systems by utilizing novel dual-functionalized luminescent MOF sensors. [ABSTRACT FROM AUTHOR]

Three new complexes, namely, [Cu2(H2bdcpb)2(pyridine)2] (1), [Cu3(bdcpp)2(CH3NCH3)(H2O)] (2), and [Cu2(H2bdcpp)2(H2O)2]·2H2O (3), have been synthesized through the hydro/solvothermal reaction of cupric nitrate and lab-synthesized 1,3-bis(2′,4′-dicarboxylphenyl)benzene (H4bdcpb) or 2,6-bis(2′,4′-dicarboxylphenyl)pyridine (H4bdcpp) in the presence of different solvent systems. Isostructural complexes 1 and 3 show dinuclear [Cu2(COO)4] covalent modes with different coordinate solvent molecules. In complex 2, a two-dimensional covalent layer is generated from one-dimensional loop chains interconnected by [Cu2(COO)4] paddle-wheels. Structural analyses revealed that the framework stability of complexes 1–3 originated from molecular custom-designed [Cu2(COO)4] paddle-wheel units by symmetrical 2′,4′-dicarboxyl polyaromatic ligands. Three new complexes have been synthesized through the hydro/solvothermal reaction of cupric nitrate and two lab-synthesized polycarboxylates in the presence of different solvent systems. Among them, two isostructural complexes show dinuclear [Cu2(COO)4] covalent modes, while the other complex is a two-dimensional covalent layer. Structural analyses revealed that the framework stability of the complexes originated from molecular custom-designed [Cu2(COO)4] paddle-wheel units. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract High activity and good durability of electrocatalysts are of significance in practical applications of fuel cells. Among them, multi-component metallic hollow nanocages/nanoframes show great potential as advanced catalysts because of their highly open structures, large surface area and good stability. Herein, we report a general uric acid-mediated solvothermal method for shape-controlled synthesis of rhombic-like Pt 35 Cu 65 hollow nanocages (HNCs) with uric acid as co-reductant and co-structure-directing agent. Uric acid and cetyltrimethylammonium chloride (CTAC) played important roles in the hollow cages. The specific architectures showed remarkably enhanced catalytic properties towards glycerol oxidation reaction (GOR), ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR) with the enhanced specific activity, outperforming commercial Pt/C (20 wt%). This work provides a new avenue for rational design of novel bimetallic nanocatalysts with enhanced characters in energy storage and conversion. [ABSTRACT FROM AUTHOR]

By systematic change of the solvothermal synthesis, three new coordination polymers, [Cd(L)∙(H2O)]∙2H2O (1), [Cd(L)∙(H2O)]∙H2O (2), and [Cd(L)] (3), have been synthesized based on a tritopic ligand 4-(pyridin-3-yl)isophthalic acid (H2L). Compounds 1 and 2 show very similar two-dimensional (2D) bilayers further linked by interlayer hydrogen bonds into three-dimensional (3D) supramolecular structures, while 3 displays a 3D structure constructed form one-dimensional (1D) Cd-carboxyl chains. Notably, 1 and 2 have a pair of unusual isomers with the opposite orientation of coordinated H2O on the metal centers, leading to different hydrogen bonding interactions. Thermal stabilities and solid-state photoluminescences for 1-3 were also investigated. [ABSTRACT FROM AUTHOR]

Hydrothermal reaction of flexible 4,4′-oxybis(benzoic acid) (H 2 oba), semi-rigid 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (bpt) and Cu(OH) 2 led to an interesting 2D → 3D polythreaded architecture of MOF [Cu 2 (bpt) 2 (oba) 2 (H 2 O)] n ·4nH 2 O ( 1 ). Accomplished with the rising synthesis temperature, two chiral MOFs [Cu 4 (bpt) 4 (oba) 4 ] n ( L - 2 and D - 2 ), have been obtained from the congenetic nonchiral precursors upon spontaneous resolution, which represent a rarely example of temperature-induced threefold interpenetrating enantiomerically arm-shaped MOFs constructed from achiral symmetrical ligands. [ABSTRACT FROM AUTHOR]

One new coordination polymer has been synthesized hydrothermally under the intervention of Ni(II) salts, 4,4′-sulfonyldibenzoate (H2sdba) with neutral linkers 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (bpt), formulated as: [Ni(bpt)(sdba)(H2O)3]n (1). X-ray structural analysis reveals that polymer 1 displays one-dimensional zigzag chain with alternating intersectional terminal sdba units. The interactions of 1 D chains by pseudo-watertapes result in the formation of 3 D supramolecular network. Interestingly, two types of hydrogen bonding left- and right-handed helices appear simultaneously in the mesomeric framework 1. [ABSTRACT FROM AUTHOR]

A novel 3D NbO metal-organic framework, [Cd 2 (pam) 2 (bpt) 2 (H 2 O)] n ·0.68nH 2 O ( 1 ) (H 2 pam = pamoic acid and bpt = 2,5- bis (4-pyridyl)-1,3,4-thiadiazole), has been synthesized by the structural cooperation of well-chosen flexible aromatic acid and rigid bipyridyl ligand. The rare severely distorted mixed-ligand mesomeric networks accommodate two individual heterochiral frameworks interpenetrating with each other. The bulk materials of 1 display excellent fluorescent properties. [ABSTRACT FROM AUTHOR]

A new complex,[Co2(OH)2L2(phen)2(H2O)2]·2(HL) (1) (HL = 2-fluoroisonicotinic acid, phen = 1,10-phenanthroline), has been synthesized using the slow-layered diffusion technique at room temperature. Single crystal X-ray analysis revealed that complex1is a dinuclearcobalt(II) complex connected by hydroxyl oxygen. The thermal stability was studied by thermogravimetric analysis (TGA). In addition, the variable-temperature magnetic property of the complex has been also discussed. The negativeθ, J or −E2/k values can be indicative of an overall antiferromagnetic coupling in addition to single-ionspin-orbital coupling. An interesting dinuclearcobalt(II) complex based on 2-fluoroisonicotinic acid were synthesized and structurally characterized. The two Co(II) centers are linked by μ2-OH−groups and there are uncoordinated HL molecules in the structure too. The thermal and the variable-temperature magnetic properties of the complex are also discussed. The negative θ,Jor −E2/kvalues can be indicative of an overall antiferromagnetic coupling in addition to single-ionspin-orbital coupling. [ABSTRACT FROM AUTHOR]

A new lead coordination polymer [Pb2(mip)2] (1) has been synthesized under the intervention of polycarboxylic acid by hydrothermal method (H2mip = 5-methylisophthalic acid). X-ray single-crystal structure determination reveals that the polymer crystallizes in monoclinic C2/c space group:a= 21.118(2) Å,b= 8.0055(7) Å,c= 25.556(3) Å, and β = 111.1730(10)°. The Pb(II) cations are connected by four mip anions to produce a 2D (6,3) double-layered framework. It should be noted that four-membered rings by two Pb atoms with twoμ-O atoms of mip groups link each other to form a one-dimensional Pb–O chain through a corner-sharing Pb center. [ABSTRACT FROM PUBLISHER]

An unusual heterometallic 3D framework, [Zn2Ca(mip)2(Hmip)2(bpe)] n ( 1), was synthesized by using an alkali-earth metal (calcium) and a d10 metal (zinc) under hydrothermal conditions [H2mip = 5-methylisophthalic acid, bpe = 1,2-bi(4-pyridyl)ethene]. Single-crystal X-ray analysis shows that complex 1 is a pillared-grid metal-organic framework (MOF) with nanosized parallelogram channels fully occupied by dangling Hmip- pendants. The most fascinating structural feature of the complex is that the achiral framework pillared by rod-like bpe is assembled by opposite chiral covalent sheets arranged alternatingly with single left- or right-handed helical chains. Topologically, the framework can be simplified as a distorted uninodal pcu net with the Schläfli symbol of {412 ·63}, which is rare representative of an achiral pillared-layer MOF with chiral sheets comprising only one type of helical chains. [ABSTRACT FROM AUTHOR]

Assembly of 5-methoxyisophthalic acid (H2moip) with cadmium(II) ions in the presence of neutral ancillary 1,3-bis(4-pyridyl)propane (bpp) yields a new coordination polymer, [Cd(moip)(bpp)(H2O)]n·nH2O ( 1). X-ray single-crystal diffraction determination reveals that complex 1 crystallizes in the space group C2/ c of monoclinic crystal system: a = 14.545(2), b = 18.749(3), c = 17.359(3) Å, β = 105.480(2)º. Complex 1 is a 4-connected 3D diamondoid topological framework with a 2-fold interpenetration. Interestingly, the dense adamantine cages with inherent microporous structure are filled with free water molecules to further stabilize the coordination network. [ABSTRACT FROM AUTHOR]

A new complex [Pb(HL)(bipy)0.5] (HL = N-[(3-carboxyphenyl)-sulfonyl]glycine dianion, bipy = 4,4' -bipyridine) has been synthesized from the reaction of N-[(3-carboxyphenyl)-sulfonyl] -glycine with Pb(CH3COO)2· 3H2O in the presence of bipy at 70°C and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in triclinic, space group P-1 with a = 4.9448(4) Å, b = 11.5868(9) Å, c = 14.1272(11) Å, α = 78.7020(10)°, β = 80.1500(10)°, γ = 83.3080(10)°, the final R = 0.0195 and wR = 0.0491. X-ray analysis reveals that the crystal structure is constructed by mixed ligands. HL2 - acts as bridging ligand to link two adjacent metal ions to form a one-dimensional chain. These chains are further cross-linked by bridging bipy ligands along the c axis to generate a 2D layer. Lead(II) ions are six-coordinated with a distorted octahedral environment geometry. [ABSTRACT FROM AUTHOR]

Abstract: An observer-based control approach is proposed for generating and manipulating projective synchronization of a general class of chaotic maps in any dimension. The proposed approach overcomes some limitations in extent work, capable to execute the control for chaotic systems without restriction of partial-linearity, achieve a full-state synchronization and manipulate the outcome of the synchronization by directing the scaling factor. The feasibility of the control is illustrated on a generalized Hénon map and a second-order map. We also show that the control scheme is robust in presence of noise. [Copyright &y& Elsevier]

This Letter reports a feedback control method to create a Hopf–Hopf interaction bifurcation that could lead to a torus solution of maps. The implicit forms of the eigenvalue assignment and the transversality condition of the bifurcation are proposed for designing control gains. With the aid of a washout-filter feedback controller, we show the application of the technique in four- and five-dimensional maps. [Copyright &y& Elsevier]

• Four new solvent-regulated congenetic zinc(II)-based MOFs were synthesized solvothermally. • Some physico-chemical properties of the MOFs materials were characterized. • Various frameworks including 1D loop chains, 2D sql plane and 2D bilayered structure were created. • This approach for solvent-regulated strategy to allow the structural fine-tuning provides a good role model in reticular chemistry. Four new congenetic zinc(II) MOFs, namely [Zn 5 (bdcpp) 3 (DMF)(H 2 O) 4 ] n · x (solvent) (1), [Zn 2 (bdcpp)(Hbdcpp)] n · y (solvent) (2), [Zn 2 (bdcpp)(DMF)(H 2 O) 2 ] n (3), and [Zn 2 (bdcpp)(NMP)(H 2 O) 2 ] n (4) (H 4 bdcpp = 2,6-bis(2′,4′-dicarboxylphenyl)pyridine, DMF = N,N'-dimethyl formamide, NMP = N -methyl-2-pyrrolidone), have been synthesized solvothermally with different solvent systems. Stabilized by Zn 2 (COO) 4 paddle-wheel building blocks, the resulting MOFs 1 – 4 represent diverse structural features. Structurally, 1 is a rarely 3,4- c binodal 2D bilayered framework, 2 possesses a 4- c 2D (4,4) sql planar network accommodating two kinds of hetero chiral helix chains, 3 and 4 are isostructural 1D loop ladder chains except different solvent molecules occupying the axial terminals of Zn 2 (COO) 4 paddle-wheels. This approach based on solvent-regulated strategy aiming to allow the structural fine-tuning provides a good role model in reticular chemistry. Complexes 1 – 3 display excellent solid-state photoluminescence stemming from the metal-to-ligand charge transfer or intraligand charge transmission. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract It is a great challenge to develop simple approach to construct three-dimensional (3D) bimetallic alloyed nanoframes (NFs) with tunable surface structures, albeit with the availability of noble metal NFs in catalysis. Herein, a one-pot solvothermal method was employed for scalable preparation of uniform hollow PtCu rhombic dodecahedron nanoframes (PtCu RDNFs) in the presence of cetyltrimethylammonium chloride (CTAC), where diglycolamine (DGA) served as the co-reductant and co-structure director. The above architectures had the larger electrochemically active surface area (ECSA, 36.85 m2 g−1 Pt) than that of commercial Pt black (15.85 m2 g−1 Pt), along with the improved catalytic characters for hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) in acid electrolytes alternative to those of Pt black. It demonstrates great potential applications of PtCu RDNFs in fuel cells and beyond. [ABSTRACT FROM AUTHOR]

Abstract: Via hydrothermal synthesis, the self-assembly of d10 metal, 2,4′-dipyridylamine (L) and 1,3-adamantanediacetic acid (H2ADA) generated two unprecedented coordination polymers [Zn(ADA)(L)] n (1) and [Cd(ADA)(L)2] n (2). Complex 1 possesses a novel 1D looped-chain topology structure decorated with arms. Complex 2 shows an extended threaded framework involving 2D coordination layers of square (44) topology with dangling ligands, which gives the novel (2D→3D) polythreaded array. To the best of our knowledge, complex 2 is the first example with four dangling arms coordinated in the axial sites of dinuclear nodes. In addition, both of the complexes show strong photoluminescence at room temperature, and may be good candidates for potential luminescence materials. [Copyright &y& Elsevier]

Abstract: Two new isomeric complexes, namely {[Cu(fum)(tpy)]·5H2O} n (1) and [Cu2(fum)2(tpy)2]·4H2O (2), have been synthesized simultaneously from the reaction of Cu(fum) with tpy (where fum=fumarate, tpy=2,2′:6′,2″-terpyridine) under mild condition. The crystal structures of complexes were determined by X-ray single-crystal diffraction. Complex 1 stabilizes in an unusual 1D water tape notated T4(2)10(2), which is directed by two chiral helical water chains; binuclear complex 2 represents a complicated (6,3)-connected framework via supramolecular interactions. Additionally, complex 1 exhibits weak ferromagnetic behavior. [Copyright &y& Elsevier]

Abstract: A novel coordination polymer based on silver(І) and mixed ligands {[Ag2(bpdc)(bpp)(H2O)]·2H2O} n (1) (H2bpdc=2,2′-bipyridyl-4,4′-dicarboxylic acid, bpp=1,3-bis(4-pyridyl)propane), has been prepared by hydrothermal method. Compound 1 has a 2D polymeric structure extended with subunits tetranuclear silver with Schläfli symbol {3^12;4^9;5^6;6^9}{3^18;4^22;5^5}. Compound 1 represents an Ag-containing polymeric compound possessing room-temperature luminescence. [Copyright &y& Elsevier]

Abstract: Rectangle-like tetrameric water clusters associate with sulfate anions and coordinated water molecules into a 2D honeycomb-like layer via hydrogen-bonded interactions. The 2D layer acts as “host” supporting the metal–organic “guest” into a 3D supramolecular architecture. [Copyright &y& Elsevier]