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In this work, four different bis(imidazole) ligands, namely 1,4-bis(1-imidazolyl)benzene (bib), 4,4′-bis(1-imidazolyl)biphenyl (bibp), 1,4-bis (imidazol-1-ylmethylene)benzene) (bimb) and 4,4′-bis(imidazol-1-yl)diphenyl ether (bidpe), were used as the second ligand to give rise to the structural diversity of a coordination polymer based on the cobalt-miipa (H2miipa = 5-(2-methylimidazol-1-yl) isophthalic acid) system. In compound 1, miipa2− coordinates to Co(II) atoms to form the Co-miipa 3D network. On introducing linear bis(imidazole) ligands with different lengths and rigidities into the Co(II)-miipa system, the obtained compounds 2–4 form similar three-fold interpenetrating 3D MOFs constructed from the Co(II)-miipa layers pillared by bis(imidazole) ligands. While introducing the V-shaped half-flexible bis(imidazole) ligands, the obtained compound 5 exhibits a 2D double-layered network built from the Co(II)-miipa 1D quadrangular prism linked by the bis(imidazole) ligand. Each 2D double layer is further interlocked with two neighboring ones to produce an interesting 3D framework. Significantly, CoNC-5 derived from a mixture of dicyandiamide (DCD) and compound 5 with a low void volume shows a superior electrocatalytic performance for the oxygen reduction reaction. The Eonset (0.974 V) and E1/2 (0.830 V) of CoNC-5 in O2-saturated 0.1 M KOH at 1600 rpm and 5 mV s−1 are superior to those of Pt/C (0.968 and 0.799 V). The JL value of CoNC-5 (JL = 5.29 mA cm−2) is higher than that of Pt/C (5.09 mA cm−2). [ABSTRACT FROM AUTHOR]

The urothermal reactions of Co(II)/Zn(II) salts with the diverse carboxylic acid and 1,3,5,-tris(1-imidazolyl)benzene(tib) ligands afforded three novel MOFs, namely, [Co3(tib)2(abdc)2(ox)]2·6H2O (1), [Co3O(tib)(abdc)2(DMI)]·2DMI·2H2O (2) and [Zn3I2(tib)2(napdc)2]·2DMI·2H2O (3), (H2abdc = 5-amino-1,3-benzenedicarboxylate, H2napdc = 1,4-naphthalene dicarboxylic acid and DMI = 1,3-dimethyl-2-imidazolidinone). In compounds 1 and 2, the Co(II) atoms are connected by polycarboxylate ligands to form two-dimensional (2D) layers that are pillared by tib ligands leading to the formation of 3D porous frameworks. In compound 3, the Zn(II) atoms are linked by tib ligands to form one-dimensional ribbon-like chains which are further connected by polycarboxylate ligands, making a 3D framework possible. Compound 1 can selectively adsorb unsaturated hydrocarbon molecules (C2H2 and C2H4) and saturated hydrocarbon molecules (C2H6 and CH4). Specifically, compound 1 has high IAST selectivity for acetylene and methane (0.50 : 0.50, v/v) at 273 K and 1 bar. DFT calculations reveal that the π-conjugated hexagonal carbon ring may be the primary adsorption site because there are π–π interactions between the unsaturated hydrocarbon molecules (C2H2 and C2H4) and the π-conjugated hexagonal carbon ring in the framework of compound 1. [ABSTRACT FROM AUTHOR]

Different aromatic polycarboxylic acids are employed as auxiliary ligands to give rise to structural diversities in Co(II)-tpt (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine) frameworks. By introducing various secondary aromatic polycarboxylate anions, namely, biphenyl-3,4′,5-tricarboxylic acid (H3bpt), 1,3,5-benzenetricarboxylic acid (H3btc) and 2,6-dimethyl pyridine-3,5-dicarboxylic acid (H2dmdcpy) into the Co(II)-tpt system (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine), four new complexes [Co3(tpt)2(Hbpt)3]·0.5DMDP (1) (DMDP = N,N′ = dimethylpropyleneurea), [Co3(btc)2(tpt)(H2O)3]·3H2O (2), [Co2(btc)(tpt)2Cl]·DMDP·1.5H2O (3) and [Co(tpt)(dmdcpy)]·H2O (4) were obtained. Complexes 1 and 2 reveal amazing 3D networks in which the polycarboxylate ligands and Co(II) ions connect with each other to form regular 3D porous frameworks with 1D cylindrical channels partitioned by virtue of the tpt ligands. Complexes 3 and 4 exhibit unusual 3D frameworks constructed from the Co–polycarboxylate layers pillared by tpt ligands. In addition, compound 1 was chosen as a precursor to prepare Co, N-codoped porous carbon materials (denoted as CoNC) as an eletrocatalyst for oxygen reduction reactions. In particular, the effect of different nitrogen sources on the electrocatalytic performance of MOF derived carbon materials was investigated. We found that although different nitrogen-containing ligands have a certain effect on the electrocatalytic performance of the synthesized CoMOF derived carbon materials, the additional nitrogen source has a significant effect on it. CoNC-A derived from compound 1 exhibits greater limiting current density than that of a Pt/C catalyst, while CoNC-B derived from a mixture of compound 1 and dicyandiamide shows almost identical onset potential but remarkably more positive half-wave potential as well as higher limiting current density as compared to commercial Pt/C catalysts. [ABSTRACT FROM AUTHOR]

Three 3D polymeric complexes containing polynuclear Co(II) units, [Co3(bpda)3(bib)2]·H2O (1), [Co5(OH)2(H2O)2(bpda)4(bib)2]·2H2O (2), and [Co2(OH)(bib)(bpt)]·H2O (3) (H2bpda = biphenyl-2,4′-dicarboxylic acid, H3bpt = biphenyl-3,4′,5-tricarboxylic acid, bib = 1,4-bis(1-imidazolyl)benzene), have been prepared by urothermal synthesis. Complex 1 exhibits an unusual (4,6)-connected 3D network based on binuclear Co(II) clusters and Co2+ centers bridged by bpda2− and bib ligands. Complex 2, containing a novel pentanuclear Co(II) cluster, features a porous 3D MOF with a regular nanosized tunnel. Complex 3 contains an interesting tetranuclear Co(II) cluster and displays an amazing 3D porous MOF built from double-layered 2D [Co2(μ3-OH)(bpt)3]n networks pillared by two rows of bib spacers. In the title complexes, polycarboxylate acids serve to construct and stabilize the polynuclear Co(II) clusters, while bis(imidazole)s help to expand the dimensionality of MOFs. Complexes 2 and 3 show antiferromagnetic properties. Compound 3 with high surface area, high yield, high purity, and high chemical stability was used as a precursor to fabricate Co,N-codoped porous carbon materials by simple carbonization under an Ar atmosphere. The catalytic properties of the Co,N-codoped porous carbon material derived from complex 3 (denoted as CoNC-3) as an ORR electrocatalyst were studied. CoNC-3 displays superior electrocatalytic performances for the ORR. [ABSTRACT FROM AUTHOR]

Two related three-membered series of nonlinear aminophenylferrocene and diphenylaminoferrocene complexes were prepared and characterized by 1H and 13C NMR spectroscopy. The first series consists of 4-(diphenylamino)phenylferrocene (TPA-Fc, 1a), its dimethoxy-substituted tetraphenylphenylenediamine derivative (M2TPPD-Fc, 1c), and the triphenylamine-bridged bis(ferrocenyl) complex (Fc-TPA-Fc, 1b). The second series involves bis(4-methoxyphenyl)aminoferrocene (M2DPA-Fc, 1d), 4-methoxyphenylaminoferrocene (MPA-Fc) with N-phenyl-appended terminal TPA (1e), and the corresponding bis(MPA-Fc) complex with bridging TPA (1f). The structure of complex 1d was further confirmed by single crystal X-ray diffraction. Combined investigations, based on anodic voltammetry, UV-vis-NIR spectroelectrochemistry and density functional theory (DFT) calculations, were conducted to illustrate the influence of the integration of multiple redox-active components on the sequential oxidation of these complexes. The first anodic steps in 1a–1f are localized preferentially on the ferrocenyl units, followed by oxidation of the TPA or TPPD moieties (absent in 1d). Irreversible oxidation of the ferrocene-appended strong donor DPA/MPA units in 1d–1f terminates the anodic series. The one-electron oxidation of the triphenylamine-bridged diferrocenyl (1b) and bis(phenylaminoferrocenyl) (1f) complexes triggers their facile redox disproportionation to dicationic bis(ferrocenium) products. [ABSTRACT FROM AUTHOR]

The first Cu-catalyzed cascade sp3 C–H bond oxidative functionalization of the 2-ethylazaarenes has been developed. The two different sp3 C–H bonds in 2-ethylazaarenes are selectively oxidized and four new types of bonds (C=O, C=N, C–C, C–O) are constructed in one operation. Starting from the simple substrates and cheap nitro source, this reaction provides an efficient approach to produce new kinds of isoxazolines. [ABSTRACT FROM AUTHOR]

Three inorganic–organic compounds based on [MoxOy]n−chains, [Ag4(3-pttz)2Mo3O10] (1) (3-pttz = 5-(3-pyridyl) tetrazolate), [Ag4(2-pttz)2Mo4O13] (2) (2-pttz = 5-(2-pyridyl) tetrazolate), and [Ag4(pzttz)2Mo4O13] (3) (pzttz = 5-(pyrazinyl) tetrazolate), have been self-assembled, accompanied by in situformation processes of the 5-substituted tetrazolate ligands under hydrothermal condition. Compound 1features a 3D framework composed of [Mo3O10]2−chains cross-linked by [Ag4(3-pttz)2]2+belts. Compounds 2and 3reveal the 3D structures based on [Mo4O13]2−chains pillared by silver tetrazolate polymeric chains. The three title compounds represent the first three examples that the tetrazolate ligands are introduced into the backbones of the [MoxOy]n−anion chains. [ABSTRACT FROM AUTHOR]

Five novel hybrid compounds, [Mo8O26Cu2(4-abpt)2]n·4nH2O (1), (4-H2abpt)2[Mo8O26] (2), [Mo8O26Cu2(3-abpt)2(H2O)2]n(3), [MoO4Cu(3-abpt)(H2O)]n(4), and [Mo6O19Co(3-abpt)2]n·4nH2O (5) were prepared by reacting MoO3/(NH4)6Mo7O24with 4-amino-3,5-bis(3/4-pyridyl)-1,2,4-triazole (3/4-abpt) and corresponding metal salts. Compound 1is a 2D coordination polymer containing extended γ-[Mo8O26]4−and [Cu2(4-abpt)2]4+ribbons. Compound 2is a supramolecular hybrid aggregate composed of H-bond linking β-[Mo8O26]4−and 4-H2abpt2+. Compound 3exhibits a 2D rectangular network constructed by isolated β-[Mo8O26]4−clusters and [Cu2(3-abpt)2]4+. In compound 4, each MoO42−anion links two Cu(ii) ions to form a S-type [CuMoO4]nchain, which is further linked by bidentate 3-abpt to form a 2D wave-like network. In complex 5, unprecedented cyclic [Mo6O19]2−cluster links two neighbouring hexamolybdates and two Co(ii) ions to form a 2D [CoMo6O19]nnetwork, which is further pillared by tetradentate 3-abpt to generate a 3D metal–organic framework. These compounds are thermally stable under 250 °C. The composites of the final residues were analyzed by PXRD. [ABSTRACT FROM AUTHOR]

Biodegradable copolymers with molecule inclusion ability was prepared by introduction of β-cyclodextrin into poly(aspartic acid) matrices. The ibuprofen loading and dissolution properties of poly(aspartic acid)–β-cyclodextrin were investigated. [ABSTRACT FROM AUTHOR]

Eu2+ was used to substitute Ca in the orthorhombic KCoO2-type layered CaTiN2 to form a Ca1−xEuxTiN2 solid solution, which showed a limited substitution around x = 0.35 with the tetragonality enhanced but the orthorhombic symmetry retained and inaccessibility for the end member EuTiN2. This was in contrast with the full solid solution Ca1−xSrxTiN2, which realized a structural transition from orthorhombic to tetragonal at x = 0.5, even though Eu2+ and Sr2+ ions have similar sizes. The Eu substitution for Ca reduced the dielectric permittivity of CaTiN2 owing to the reduced structural distortion arising from the enhanced tetragonality with the substitution. First-principle theoretical calculations on the total energies and formation energies considering the 4f electrons of Eu ions and the related magnetism were performed to understand the structural stability of the hypothetical EuTiN2. Compared with CaTiN2 and SrTiN2, EuTiN2 has much higher formation energies, making it inaccessible at high temperature. The evolutions of the experimentally observed and calculated lattice parameters of the Ca1−xEuxTiN2 solid solution showed a preference for the orthorhombic phase over the tetragonal phase for the hypothetical EuTiN2, revealing a different coordination chemistry of Eu2+–N to Eu2+–O through the comparison of the structural variations of ATiN2 and ATiO3 (A = Ca, Sr, Eu). [ABSTRACT FROM AUTHOR]

Six novel Co(ii) coordination polymers, namely, [Co10L6(OH)2(H2O)9]·10.5H2O (1), [Co3L2(3-abpt)2]·4H2O (2), [Co3L2(4-azpy)2(H2O)2(EtOH)] (3), [Co3L2(4,4′-bipy)2(H2O)2(MeCN)] (4), [Co3L2(4,4′-bipy)2] (5), and [Co5L2(OH)2(ina)2(H2O)2] (6) (H3L = 2,2′-phosphinico-dibenzoic acid, 3-abpt = 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole, 4-azpy = 4,4′-azobispyridine, 4,4′-bipy = 4,4′-bipyridine, Hina = isonicotinic acid), have been hydrothermally synthesized and their magnetic properties have been characterized. The L3− anion displays six types of coordination modes in the compounds. Compound 1 exhibits a novel 1D ladder-like structure, which consists of non-centrosymmetric Co10 units. Compounds 2–4 comprise 2D networks assembled from Co3L2 chains and N-heterocyclic linkers. Compound 5 comprises a 3D framework built from six neighboring parallel Co3L2 ladders bridged by 4,4′-bipy linkers. Compound 6 features a 3D framework that exhibits pcu topology with the Schläfli symbol of (412·63) using a pentanuclear [Co5(OH)2]8+ cluster as the node. Variable-temperature magnetic susceptibility studies indicate that the six coordination polymers exhibit remarkable magnetic behavior such as spin-canted antiferromagnetism and spin glass, which were found to coexist in compound 6. [ABSTRACT FROM AUTHOR]

A series of ruthenium(ii) complexes [{RuCl(CO)(PMe3)3(–CH=CH–)}nX], 1a–1c (1a: n = 3, X = 3,3′′-dimethyl-2,2′:3′,2′′-terthiophene; 1b: n = 2, X = 2,2′-bithiophene; 1c: n = 2, X = 2,3-bis(3-methylthiophen-2-yl)benzothiophene) and [{Cp*(dppe)2Ru(–C≡C–)}3X], 1d (X = 3,3′′-dimethyl-2,2′:3′,2′′-terthiophene), were prepared and characterized by 1H, 13C and 31P NMR. Their redox, spectroscopic and bonding properties were studied with a range of spectro-electrochemical methods in combination with density functional theory calculations. The first two anodic steps observed for 1a and 1d are largely localized on the lateral frameworks of the molecular triangle, the direct conjugation between them being precluded due to the photostable open form of the dithienyl ethene moiety. The third anodic step is then mainly localized on the centerpiece of the triangular structure, affecting both bithiophene laterals. The experimental IR and UV-vis-NIR spectroelectrochemical data and, largely, also DFT calculations account for this explanation, being further supported by direct comparison with the anodic behavior of reference diruthenium complexes 1b and 1c. [ABSTRACT FROM AUTHOR]

By introducing multiple molecule/intermolecular dynamic reversible hydrogen bonds into the polydimethylsiloxane elastomer system, a solid polymeric electrolyte with high ion conductivity (2.5 × 10−4 S cm−1) and a stable electrochemical window (>5 V) shows a fast self-healing speed. [ABSTRACT FROM AUTHOR]

A complexone analog chemosensor, H2L, bearing chelating bis(2-pyridylmethyl) amine and alizarin groups was synthesized via the Mannich reaction. H2L chromically responds to OH−, F−, CH3COO−, and H2PO4− in DMF, CH3CN, and acetone, but not in CH3OH or H2O. The addition of F− ions to H2L selectively induces a significant and visible color change in acetonitrile and shifts both methylene proton signals upfield. H2L also exhibits visible responses to Mg2+, Sr2+, Ba2+, Tb3+, Cu2+, Co2+, Ni2+, Zn2+, Mn2+, Cd2+, and Fe3+ in solution. AlCl3 can form an Al : L = 2 : 3 complex that not only changes the color of the DMF solution, but also significantly increases its fluorescence intensity. The limit of fluorescence turn-on detection for AlCl3 in DMF is 2.7 × 10−8 M, which is an order higher than those of other anthraquinone sensors reported in the literature. NMR spectroscopy shows that hydroxyl is not deprotonated upon interacting with Al3+, but will be partially deprotonated in the presence of Zn2+. Contrary to the complexone, the H2L–Ce(iii) complex does not react chromically to F−. However, the H2L–NiCl2 complex responds chromically to F−, with higher sensitivity (LOD = 1.3 × 10−6 M F− in acetonitrile) than free H2L. The spectral changes in the presence of F− are similar to that of OH−; however, the spectrum shifts slightly to a longer wavelength and is more sensitive to both H2L and the H2L–NiCl2 complex. Moreover, 4% or less H2O in the solvent essentially has no influence on the F− sensitivity; however, high water content significantly decreases the F− sensitivity. The spectral changes of the Zn2+, Cu2+, Fe3+, Ce3+, and Ni2+ complexes in the presence of different NaOH concentrations were also investigated. [ABSTRACT FROM AUTHOR]

Four new Ni(ii) coordination polymers, namely, [Ni(HL)(bpe)(H2O)2]n·nH2O (1), [Ni2(L)(bpe)(μ3-OH)(H2O)]n·3nH2O (2), [Ni(L)(bpe)(H2O)]n·[Ni0.5(bpe)0.5(H2O)2]n·nH2O (3) and [Ni(HL)(bpe)(H2O)]n·3nH2O (4) based on flexible ligands 5-(3-carboxybenzyloxy)-isophthalic acid (H3L) and 1,2-bis(4-pyridyl)ethane (bpe) have been successfully synthesized under different conditions. Compounds 1 and 4 present two-dimensional sql layer structures, while compound 2 exhibits a three-dimensional structure based on a tetranuclear Ni(ii) cluster with (3,8)-connected tfz-d topology, and compound 3 consists of a 2D sql anionic layer and 1D linear cationic chains, which are further entangled to give an interesting 2D + 1D → 3D poly-pseudorotaxane framework. To determine the relationship between these diverse structures and external synthetic influence factors, we systematically change the molar ratios of the reactants, solvent and pH and study their effects. Furthermore, the structural transformation from compound 4 to 3 has also been investigated. [ABSTRACT FROM AUTHOR]

A Rh/Ni-catalyzed cascade sequence of allylamine isomerization and hydrophosphonylation to synthesize α-aminophosphonates has been disclosed. The reaction, which not only allows the generation of widespread valuable α-aminophosphonates under simple systems and mild conditions, but also enriches the process of olefin isomerization–addition both in catalytic systems and various reaction types. [ABSTRACT FROM AUTHOR]

A homochiral three-dimensional framework material, [Cu7(4-bpt)6(CN)(H2O)] (1) (4-bpt = 3,5-bis(4-pyridyl)-1,2,4-triazole), has been successfully synthesized by solvothermal reaction, which is generated through an unusual spontaneous asymmetrical crystallization from achiral precursors, and its photocatalytic properties in degradation of organic dyes are also investigated. [ABSTRACT FROM AUTHOR]

The hydrothermal reaction of silver nitrate and 2,2'-phosphinico-dibenzoic acid (H3L) with different metal to ligand ratios under hydrothermal conditions yielded two unusual complexes with the formulae of [Ag(H2L)]n (1) and [Ag3(L)]n (2). Both complexes were well characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopic and fluorescence studies. Complex 1 crystallizes in a centrosymmetric Pbcn space group and presents a two-dimensional (2D) layer structure through silver(I)-aromatic interaction, whereas complex 2 adopts a noncentrosymmetric Iba2 space group, in which the different coordination modes of the four groups around the phosphorus atom in the L3-ligand occurs. Both complexes display green emissions, assigned as the ligand-to-metal charge-transfer character. [ABSTRACT FROM AUTHOR]

Seven coordination polymers, namely [Mn(4-cptpy)2]n (1), [Co(4-cptpy)2]n (2), [Mn3(4-cptpy)6(H2O)]n. 2nH2O (3), [Co(4-cptpy)(HCOO)(H2O)]n'nDMF (4), [Zn2(4-Hcptpy)2Cl4]n.2nC2H5OH.nH2O (5), [Co4- (3-cptpy)4(HCOO)4(H2O)2]n (6), and [Mn(3-cptpy)2]n (7) (4-Hcptpy = 4-(4-carboxyphenyl)-4,2':6',4"-terpyridine; 3-Hcptpy = 4-(4-carboxyphenyl)-3,2':6',3"-terpyridine), have been synthesized under hydro- (solvo)thermal conditions and structurally characterized. A general solvothermal method is proposed for preparing carboxylate complexes in DMF solution without any basic additive. 1 and 2 possess isostructural 3D metal-organic frameworks containing nanosized cavities. 3 is a beautiful 2D coordination polymer assembled by flower-like Mn3(4-cptpy)6(H2O) subunits. 4 and 6 both display 2D polymeric networks constructed from 4/3-cptpy- ligands, in which the formate ligands originate from the hydrolysis of DMF. 5 is a 1D 21 helical chain polymer. 7 shows a 2D network with a (3.6) two-nodal kgd topology. 4/3-Hcptpy ligands display seven types of coordination modes. The zinc complex 5 emits strong violet luminescence. 1 and 2 are both thermally stable below 440 °C and exhibit antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]

Solvothermal syntheses afforded two new MOFs {[Zn2(L1)(btmbb)(H2O)4]·2H2O}n (1) and [Zn2(L1)(btmbb)2]n (2) [5,5′-(1,4-phenylenebis(methylene))bis(oxy)diisophthalic acid (H4L1), and 4,4′-bis((1H-1,2,4-triazol-1-yl)methyl)biphenyl (btmbb)]. Single crystal X-ray analyses reveal that compound 1 shows an example of a 2D non-interpenetrating network, while compound 2 is a 2D polythreading interpenetrating structure, in which two layered networks interpenetrate in a (2D/2D) parallel fashion. The different conformation of the flexible ligand might be the main factor resulting in these non-interpenetrated/interpenetrated structures. The powder X-ray diffraction, thermal stabilities, and the photoluminescence of 1–2 have also been investigated. [ABSTRACT FROM AUTHOR]

A 2D tri-layer compound {[Co8(tbip)6(H2O)9(OH)4]·12(H2O)}n(1) (H2tbip = 5-tert-butyl isophthalic acid) consisting of novel heptacobaltate clusters and single cobalt centers bridged by tbip2−ligands has been hydrothermally synthesized. The complex represents a rare example of a homometallic coordination polymer built up from both heptanuclear metal clusters and single metal centers simultaneously. The magnetic investigation reveals that the complex exhibits the overall predominance of antiferromagnetic coupling between magnetic centers. [ABSTRACT FROM AUTHOR]

A low cost and environmentally benign process for tetrabutyl titanate-controlled ring-opening polymerization of -caprolactone at ambient temperature of 10–40 °C is introduced affording poly(-caprolactone) with pre-designed molecular weights and narrow molecular weight distribution. [ABSTRACT FROM AUTHOR]