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The selective hydrogenation of the biomass platform molecule furfural (FAL) to produce furfuryl alcohol (FA) is of great significance to alleviate the energy crisis. Cu-based catalysts are the most commonly used catalysts, and their catalytic performance can be optimized by changing the preparation method. This paper emphasized the effect of calcination atmosphere on the performance of a Cu/Al2O3 catalyst for the selective hydrogenation of FAL. The precursor of the Cu/Al2O3 catalyst prepared by the ammonia evaporation method was treated with different calcination atmospheres (N2 and air). On the basis of the combined results from the characterizations using in situ XRD, TEM, N2O titration, H2-TPR and XPS, the Cu/Al2O3 catalyst calcined in the N2 atmosphere was more favorable for the dispersion and reduction of Cu species and the reduction process could produce more Cu+ and Cu0 species, which facilitated the selective hydrogenation of FAL to FA. The experimental results showed that the N2 calcination atmosphere improved the FAL conversion and FA selectivity, and the FAL conversion was further increased after reduction. Cu/Al2O3-N2-R exhibited the outstanding performance, with a high yield of 99.9% of FA after 2 h at 120 °C and an H2 pressure of 1 MPa. This work provides a simple, efficient and economic method to improve the C=O hydrogenation performance of Cu-based catalysts. [ABSTRACT FROM AUTHOR]

A novel three-dimensional homochiral porous coordination polymer was obtained by combining the luminescent component Eu(III) with an enantiomerically pure semirigid triangular organic ligand derived from (L)-α-leucine. Remarkably, it not only exhibited photoluminescence and fluorescence-based metal ion sensing properties, but also displayed enantioselective adsorption of (R)-and (S)-1-phenylethanamine and (R) and (S)-1-phenylethanol. [ABSTRACT FROM AUTHOR]

A new two-dimensional (2D) homochiral cadmium(II) coordination polymer, {[Cd4(OH)2(L)2(pea)4]·CH3OH}n (1) (pea = (S)-1-phenylethanamine), was solvothermally synthesized based on an enantiomerically pure chiral ligand (S)-5-(((1-carboxy-2-phenylethyl)amino) methyl)isophthalic acid (H3L). Crystal structure analysis shows that 1 is a 2D homochiral framework consisting of coaxial double-helical chains where a pair of left- and right-handed 21 helixes shares tetranuclear Cd cluster subunits [Cd4(μ3-OH)2]. Topologically, 1 is an interesting 3,6-connected network with the point symbol of (43)2(46·66·83). The thermal stability and solid-state optical properties, including circular dichroism, and nonlinear optical and luminescent properties of 1 were systematically investigated. Furthermore, the fluorescence response of 1 to various common solvents and metal ions was preliminarily studied. Interesting enough, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), acetone and Fe3+ ion have strong quenching effect on the fluorescence of 1, indicating that 1 has certain potential application in the visual detection of these species. [ABSTRACT FROM AUTHOR]

Two metal–organic frameworks based on a multifunctional ligand 2-(5-bromo-pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid (H3L), [Mn(HL)(C2H5OH)]n (1) and {[Zn(HL)(H2O)2]·H2O}n (2), have been hydro/solvothermally synthesized and characterized by IR, elemental analyses, X-ray powder and single-crystal diffractions, and thermogravimetric analyses. In 1, (HL)2– ligands adopt the μ3-kN,O:kN′,O′:kN′′ coordination mode and use their imidazoledicarboxylates to bis-chelate MnII into left- and right-handed helixes which are further bridged into a mesolayer structure with (4·82) topology through the coordination of their pyridyl groups. In 2, (HL)2– ligands only use their imidazoledicarboxylates to bis-chelate ZnII into linear chains which are further linked into a 2D supramolecular framework through interchain hydrogen–bonding interactions. Interestingly, the structures of 1 and 2 are mainly dominated by the bis-N,O-chelation of the imidazoledicarboxylate in (HL)2–. As for the formation of the imidazoledicarboxylate-bridged helical chains in 1 or straight chains in 2, it largely depends on the cis- or trans-chelation of two imidazoledicarboxylates around the same metal center. Magnetostructural analysis of 1 discloses that the bis-N,O-chelating imidazoledicarboxylate of (HL)2– transmits antiferromagnetic interactions along the imidazoledicarboxylate-bridged helical chain with the spin-coupling constant of –0.71 cm–1. Additionally, 2 emits greatly enhanced blue fluorescence mainly originating from the intraligand charge transition. [ABSTRACT FROM AUTHOR]

A series of metal–organic frameworks built from a propionate-functionalized purine-containing ligand 3-(6-oxo-6,9-dihydro-1H-purin-1-yl)propanoic acid (H2L), {[La(HL)3(H2O)2]·2H2O}n (1), {[Ce(HL)3(H2O)2]·4H2O}n (2), [Co(HL)2(H2O)2]n (3), {[Cd(L)(H2O)]·0.5H2O}n (4) and {[Pb(HL)(C2O4)0.5(H2O)]·2H2O}n (5), was synthesized and characterized. Isostructural 1 and 2 have polymeric chain structures further linked into 3-D porous supramolecular frameworks with 1-D open channels through complicated interchain hydrogen bonding interactions. At 77 K and 1 bar, the dehydrated porous materials 1 and 2 show adsorption behaviors with maximum nitrogen uptakes of 14 and 23 mL g−1, respectively. Complexes 3–5 are 2-D coordination polymers but have different topological structures. Metallohelicate 3 has (4,4) nets composed of left- and right-handed metal–organic helices sharing the common metal centers, but metallohelicate 4 possesses (4·82) topology and 5 has 63-topological structure. In 3 and 5, the polymeric layers are further assembled through regular interlayer hydrogen bonding interactions to form 3-D supramolecular frameworks. Additionally, the thermostabilities of 1–5 as well as the magnetism of 3 were also investigated. [ABSTRACT FROM AUTHOR]

Four cobalt(II) compounds, [Co(Bim)(IA)(H2O)2]n·0.5nH2O (1), [Co(Bim)(MA)(H2O)2]n(2), [Co2(Bim)2(MA)2]n·nH2O (3), and [Co3(Bim)4(TA)2(H2O)2]n·2.5nH2O (4), have been synthesized by solvothermal reactions of cobalt(II) salts with 1,1′-(5-methyl-1,3-phenylene)bis(1H-imidazole) [Bim] and aromatic polycarboxylic acids (H2IA = isophthalic acid, H2MA = 5-methylisophthalic acid, and H3TA = trimesic acid) as coligands. The four complexes were characterized by IR and UV−vis spectra, elemental analyses, X-ray powder and single-crystal diffractions, and thermogravimetric analyses (TGAs).1features a zigzag polymeric macrocycle chain containing a nanotubular channel, which is constructed by bridging the folded 20-membered macrocyclic [Co2(Bim)2] subunits with IA ligands.2represents a double-chain structure containing 18-membered macrocyclic [Co2(Bim)(MA)] subunits. Both3and4are 2-D porous coordination polymers but have different architectures. In3, cage-like [Co4(Bim)2(MA)4] subunits are 4-connected nodes that are further bridged by another half-set of Bim ligands to form a 2-D helical structure containing one-dimensional achiral channels and alternately arranged left- and right-handed helical tubular channels. In4, Bim ligands bridge three crystallographically independent Co centers into sharply distorted left- and right-handed helices which are further connected by TA ligands to form a meso layer about 3.0 nm monolayer thickness with a unique (3,4)-connected topology. The structural diversities of coordination polymers1–4are tuned by the flexible coordination number of Co and coligand polycarboxylates. Thermal analyses show that the main frameworks of all compounds remain stable to 352 °C. Moreover, the interesting color changes of crystals1–4, varying from pink to purple and dark blue, result from the d → d* transitions of chromophoric Co2+in different coordination geometries as determined by the UV–vis spectra in combination with crystal structure analyses. [ABSTRACT FROM AUTHOR]

An intentionally synthesized chiral terpyridyl ligand S-2(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)-benzylamino)propanoicacid(H2L) was used to construct two chiral NiIIcomplexes,[Ni2(HL)2(N3)(H2O)](N3)·19H2O (1) and [Ni2(HL)2(N3)2]·7H2O (2). Both complexes aredinuclear metallocyclic complexes. The monoanionic form (HL)−of the chiral ligand coordinates to the metal centers in a bichelatingantiparallel fashion to form the metallomacrocycles where the chiralmetallocycles Ni2(HL)2template the formationof a novel chiral 3D zeolite-like water framework with nanometer cagestrapping the metallocycles or anchor chiral water chains in the 1Dchannels of a resulting chiral 3D supermolecule, respectively. [ABSTRACT FROM AUTHOR]

The chiral Cd(II) complex {[Cd(L)(CH3COO)2(H2O)]·H2O}n {L = 1,1'-[bis-3-(3-pyridyl)pyrazol-5-yl]ferrocene} has been synthesised. The Cd(II) ion is coordinated by two pyridyl nitrogen atoms, two chelating acetate anions and one water molecule, showing a distorted pentagonal-bipyramidal coordination environment. Each ligand L serves as a bisconnector, bridging two Cd atoms through its two pyridyl moieties, to afford an infinite 1D left-handed helical chain along the a-axis with a short pitch of 5.8761 (9) Å. Moreover, all of the left-handed helical chains are joined by hydrogen bonds to form a left-handed homochiral crystal. [ABSTRACT FROM AUTHOR]

Five cation-induced complexes, (phen-dzp) [ZnBr3N3] (1), (phen-dzp) [ZnCl2Br2] (2), (phen-dzp) (H3O)2 [Fe(CN)6] (3), (phen-dzp)2 [Cu2I6] (4), and [(phen-dzp)(Ag2Br4)]n (5) [phen-dzp = (C15H14N2)2+, 6,7-dihydro-5H-[1,4]diazepino[1,2,3,4-lmn][1,10]phenanthroline-4,8-diium], have been synthesized via self-assembly in solution. The crystal structures of 1-3 show that they all crystallize in monoclinic systems with mononuclear structures. Compound 4 is a binuclear coordination polymer. Complex 5 possesses a 2-D supramolecular layer with the organic cation phen-dzp trapped in it; interestingly, each inorganic polymeric planar layer is composed of large, decagon rings formed by sharing four Br- and four [Ag2Br4] quadrilateral units with six adjacent decagon rings. The results provide insights into template effects of synthetic approaches on the construction of supramolecular compounds. The structures of 1-5 have been characterized by elemental analysis, infrared spectra, and single-crystal X-ray crystallography. Solid-state photoluminescence properties of 1-5 have been determined. [ABSTRACT FROM AUTHOR]

One Co(II) 1D chain coordination polymer {[Co(bpp)2(H2O)2] (bpp)3· (H2O)· (ClO4)2}n (bpp = 1,3-Bis(4-pyridyl)propane) has been synthesized and structurally characterized by single-crystal X-ray analysis. This compound belongs to orthorhombic system with space group Pccn. 1D chains are packed through π -π interactions and linked together by bpp ligands through hydrogen bonds to construct 2D layers. Organic ligand molecules are pillared among these parallel 2D layers to construct a 3D supramolecular inorganic-organic hybrid framework. Organic ligand bpp in this compound exhibits three unusual comformations. Studies on magnetic properties of this compound show that it presents weakly antiferromagnetic behavior. [ABSTRACT FROM AUTHOR]

Two Cd(II) 1-D chain coordination polymers with Cd-Cl-Cd-Cl 1-D chains as bases, one connected to protonated 8-aminoquinoline by intermolecular hydrogen bonds {[Cd2(μ-Cl)4(Cl)2(CH3OH)(H2O)]·(H-aql)2}n (1) (aql = 8-aminoquinoline) and the other to 8-aminoquinoline [Cd(μ-Cl)2(aql)]n (2), have been synthesized and structurally characterized by single-crystal X-ray analysis. 1 belongs to the monoclinic system with space group P2(1)/m and 2 belongs to the monoclinic system with space group C2/c. Fluorescent properties of aql, 1, and 2 showed that the fluorescence spectrum (λmax = 386 nm) of 1 is mainly of aql ππ* character. The fluorescence spectrum of 2 which emits blue-green light (λmax = 497 nm) mainly involves a metal-perturbed intraligand ππ* transition from strong covalent bonds. Thermal stabilities of 1 and 2 have also been studied. [ABSTRACT FROM AUTHOR]

Abstract: Two cadmium(II)–ntcaa coordination polymers, [Cd(phen)(ntcaa)(H2O)2] n (1) and [Cd2(4,4′-bpy)(ntcaa)2] n (2) (ntcaa=naphthalene-1,4,5,8-tetracarboxylic acid 4,5-anhydride, phen=1,10-phenanthroline, 4,4′-bpy=4,4′-bipyridine), were synthesized via hydrothermal method. The structure of compound 1 is a neutral comb-like chain with π–π interactions between the phen and naphthalene aromatic rings, while that of 2 possesses an interesting baluster structure composed of helix chain as post and 4,4′-bpy as connector. Photoluminescent investigations reveal that both compounds exhibit strong emissions in the solid state. [Copyright &y& Elsevier]

Abstract: A new three-dimensional non-interpenetrating coordination polymer, [{Cu(dps)2(SO4)}·3H2O·DMF] n (1) (dps=4,4′-dipyridyl sulfide) was synthesized and structurally characterized. 1 crystallizes in triclinic system, space group P−1 with cell parameters of a=10.9412(1)Å, b=11.8999(1)Å, c=12.5057(1)Å, V=1400.7(3)Å3, Z=2, D c=1.573gcm−3, F(0 0 0)=686, μ=1.059mm−1. R 1=0.0436, wR 2=0.1148. In the polymeric architecture, serve as bridging coligands to connect highly puckered [Cu2(dps)2] n frameworks resulting in a 3D motif containing channels for guest molecule inclusion. Quantum chemistry calculation shows that the third-order NLO properties of polymer 1 are controlled by groups and dps ligands, and metal ions have less influence on the third-order NLO properties. [Copyright &y& Elsevier]

Abstract: The assembly of Ni(II) ions with linear spacers trans,trans-muconic acid (H2L) and 4,4′-bipyridine (4,4′-bpy) has afforded a compound, [Ni(L)(4,4′-bpy)(H2O)2] n (1). Single crystal X-ray diffraction analysis reveals that both 4,4′-bpy and deprotonated H2L act as linear bridges to bind square-planar Ni(II) nodes. Achiral ligands 4,4′-bpy induced in a chiral configuration link metal nodes into chiral chains, which are further bound into homochiral sheets by rigid L. Finally, a novel 3D chiral framework forms through three-fold slantwise interpenetration of those chiral (4,4) nets. The magnetic studies in the range 2–300K show that magnetic behavior of 1 possesses a large zero-field splitting of Ni(II) ions and an anti-ferromagnetic interaction between metal centers. [Copyright &y& Elsevier]

Abstract: A new polymeric silver(I) coordination polymer, {[Ag(tptb)(MeCN)]ClO4} n (1), (tptb=2,4,6-trimethyl-1,3,5-tris(2-pyrimidinylthiomethyl)benzene), was synthesized by self-assembly reaction of tptb and AgClO4, and structurally characterized to be a isolated, 1D tubular helicate. 1 is luminescent and displays an emissive maximum at 510nm in the solid state at room temperature. [Copyright &y& Elsevier]

Abstract: Reaction of CuII, K3 [Fe(CN)6] and bidentate diimine ligands by hydrothermal synthesis under different conditions affords one novel heteronuclear FeII–CuI complex, (bipy=2,2′-bipyridine), and two homonuclear CuI complexes, [CuI(μ-CN)(bipy)]n (2) and (3) (phen=1,10-phenanthroline). Although all the three complexes are 1D cyanide bridged helical chains, they have different helicoids of pseudo-square, pseudo-trigonal and head-to-head bistrigonal for 1, 2 and 3, respectively. The structure of 1 is extended to 2D hexagonal meshed layers by the hydrogen bonding between terminal cyanides and lattice water molecules, which also contain π–π interactions between adjacent sheets. CuI ions in 1 are distorted trigonal planar coordinated by two bridging cyanides and one terminal cyanide, whereas that in 2 and 3 are pseudo-tetrahedral coordinated by two bridging cyanides and two N atoms of a diimine. Both the latter homometallic polymers exhibit similar chain structure, and these chains are close packed with their six adjacent chains in a parallel fashion along the c-axis to form a honeycomb network. It should be noted that complex 1 is the first cyanide bridged FeII–CuI complex of helical chain structure. The spectroscopic properties of complexes 1–3 have also been investigated. [Copyright &y& Elsevier]

In this article, two two-dimensional and three-dimensional metal-organic frameworks are synthesized by the self-assembly of copper(I) halide and the hexamethylenetetramine (hmt) ligand. Compound 1 is a two-dimensional metal-organic framework composed of a pyramidal Cu 4 I 5 cluster and hexamethylenetetramine, in which hmt-bridged Cu clusters form a two-dimensional (4,4)-connected net with a point symbol of (4 4 ·6 2 ) (4 4 ·6 2 ). Compound 2 is a homochiral three-dimensional metal-organic framework material generated through an unusual spontaneous crystallization from achiral precursors. The two compounds were characterized by a series of analyses such as infrared spectroscopy, elemental analysis, circular dichroism spectroscopy, and powder X-ray diffraction. Both of them exhibit unexpected stability under a wide range of conditions of acid and base. In addition, the fluorescence intensity changes regularly under acid-base conditions. Stokes shift shows a good linear relationship with -log [H + ], which makes them become promising acid-base sensors. Compounds 1 and 2 also display selective adsorption and a significant degradation effect on the organic dye methylene blue. In addition, the fluorescence study indicated that compound 2 could be used as a sensor to detect Cr 3+ ., Competing Interests: The authors declare no competing financial interest.

Five interesting metal-organic nanostructures and networks, [Ni(4)(HL)(4)(bpy)(py)(H(2)O)(5)](2) x 0.5 H(2)O (1), [Co(4)(HL)(4)(bpy)(py)(H(2)O)(5)](2) x 0.5 H(2)O (2), [Ni(4)(HL)(4)(H(2)O)(7)](n) x nH(2)O (3), [Ni(4)(HL)(4)(bpy)(2)(H(2)O)(4)](n) (4), and [Cd(4)(HL)(4)(H(2)O)](n) (5), were synthesized hydrothermally [H(3)L = 2-(pyridin-2-yl)-1H-imidazole-4,5-dicarboxylate acid, py = pyridine, and bpy = 4,4'-bipyridine]. Intriguingly, all compounds consist of novel metallacalix[4]arene building blocks M(4)(HL)(4), where doubly deprotonated HL in the same bichelating fashion of mu-kN,N':kO,N'' displays a strong coordination orientation by cooperation of the 4,5-imidazoledicarboxylate and 2-pyridyl groups. Very interestingly, the symmetry of M(4)(HL)(4) and the linkage styles between metal nodes and HL in M(4)(HL)(4) are sensitive to the reaction conditions, and the resulting structural motifs vary with secondary ligands and metal nodes. In 1 and 2, two C(1)-symmetric M(4)(HL)(4) units are bpy-bridged into dimeric chiral nanomolecules with two different cavities. As deprotonated with NaOH, the combination of Ni(II) and HL forms a pseudo-S(4)- or S(4)-symmetric M(4)(HL)(4), which further assembles into 1D chiral crystals 3 or rare 3D crystals 4 of bpy-bridged 5-fold interpenetrating diamondoid architecture with metallacalix[4]arene building blocks as novel 4-connecting nodes, and the combination of Cd(II) and HL forms an 8-connected C(2)-symmetric M(4)(HL)(4) that fabricates the alpha-Po net of 5. Notably, those large M(4)(HL)(4) units are potentially highly connected building blocks in a hierarchical assembly of metal-organic networks. Magnetic studies disclose antiferromagnetic interactions in M(4)(HL)(4) of 1-4. The magnetic data for 1, 3, and 4, all containing isomeric Ni(4)(HL)(4) units, are analyzed by an equilateral quadrangle isotropic model combined with the molecular-field approximation with J = -4.00(2), -3.39(2), and -2.72(3) cm(-1), respectively, presenting a stronger comparison between the structure and magnetism. The emission of 5 is odd, which perhaps is relative to the bichelating fashion of ligand HL and a rare coordination geometry of Cd(II). Moreover, the thermal stability and gas sorption properties of these compounds were measured.

The reactions of cobalt(II) halides and flexible ligand L [L=1,3-bis(pyrid-4-ylthio)propan-2-one] under different conditions generated a series of complexes with various structural motifs ranging from tetragonal-prismatic cages to 1-3D coordination polymers. The layer diffusion of cobalt(II) chloride and L in methanol/acetone at 25 degrees C gave rise to a 3D polymer, [Co(L)2Cl2].Me2CO. At 30 degrees C, the slow diffusion of diethyl ether into the blue dimethylformamide (DMF) solution of complex 1 afforded a 1D polymer, Co(L)Cl2(DMF)2. However, at 10 degrees C, the diffusion of diethyl ether into the DMF solution of complex 1 produced a tetragonal-prismatic cage, [Co2(L)4Cl2]Cl2.Et2O.DMF.2MeOH.4H2O. The reaction of cobalt(II) bromide and L in DMF at 10 degrees C yielded a dimer, [Co2(L)4Br2]Br2.6DMF.2H2O, with a cage structure similar to. The preparation of the series of compounds indicates the subtle relationship between structures and tunable reaction conditions. It is also found that the structural motifs vary according to the ligand conformations and that the formation of tetragonal-prismatic cages and may be templated by anionic guests. Magnetic studies on complexes in a temperature range 4-300 K disclose that L is unfavorable for a long-range magnetic interaction; however, intramolecular spin-coupling constants of -19.6 and -21.5 cm-1 for and indicate rather strong magnetic superexchanges arising from the overlap of the dz2 orbitals of the cobalt(II) and pz orbitals of the encapsulated halide anions. Electron paramagnetic resonance (EPR) spectra of complexes 3 and 4 in solution and solid give information that both complexes are high-spin cobalt(II) compounds with a rhombic distortion of the axial zero-field splitting. Interestingly, the intramolecular magnetic-exchange coupling in 3 and 4 mediated by the encapsulated anion Cl- or Br- is also reflected by the EPR spectra.

A new polymeric metal organosulfide [Cu(I)3(pymt)3]n(pymt = pyrimidine-2-thiolate) with strong red photoluminescence was synthesized through solvothermal redox reaction, and crystallographically characterized to be a one-dimensional chiral structure containing metal-metal interactions.