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A novel thio-Ritter-type reaction of alkyl bromides, nitriles, and hydrogen sulfide has been explored, providing a straightforward approach toward functionally important thioamides. This transformation features a broad substrate scope, operational simplicity, use of available feedstock chemicals, and late-stage functionalizations of bioactive molecules. The reaction mechanism is also proposed. [ABSTRACT FROM AUTHOR]

Zn(II) and Cd(II) coordination polymers constructed from a new angular bis-pyridyl-bis-amide ligand and naphthalene-1,4-dicarboxylic acid (1,4-H2NDC), {[Zn2(L)(1,4-NDC)2]·2H2O} [L = 4,4′-oxybis(N-(pyridin-3-ylmethyl)benzamide)], 1, and {[Cd2(L)(1,4-NDC)2]·EtOH}, 2, have been solvothermally synthesized and structurally characterized by using single-crystal X-ray diffraction. While complex 1 displays a 2D double layer with the rare (46·64)-5 L4 topology, complex 2 shows a 3D framework with a new (4·5·6)(45·55·69·7·8) topology. Both complexes 1 and 2 display luminescence properties and 2 exhibits a high sensitivity toward the detection of Fe3+ ions with a Ksv value of 1.9 × 104 M−1. The quenching effect can most probably be ascribed to the interactions between the metal ions and the amide carbonyl oxygen atoms. [ABSTRACT FROM AUTHOR]

One-pot solvothermal reactions of 2-aminopyridine, triethylorthoformate and sodium hydroxide with CuX (X = Br, and I) in dimethylformamide (DMF) and methanol (MeOH) afforded extended metal chains based on the linear tetracopper units, {[Cu4Br2(Dpyf)2]·DMF}n, 1, and [Cu4I2(Dpyf)2]n, 2, which were structurally identified by X-ray crystallography. Complexes 1 and 2 present closed-shell Cu(I)–Cu(I) interactions that are supported by formamidinate ligands, resulting in a face-to-side configuration and a face-to-face configuration, respectively, for the tetranuclear units. Complexes 1 and 2 represent the first example of one-dimensional (1D) coordination polymers that are based on linear tetracopper units. Moreover, complexes 1 and 2 can be regarded as copper(I) halide aggregates with the unique Cu4Br2 2+ and Cu4I2 2+ cations extending into a 1D zigzag chain and a looped chain, respectively. Complexes 1 and 2 show broad emissions at 570 and 549 nm, respectively, which can most probably be ascribed to 3d(Cu) → π* metal to ligand charge transfer. Reversible crystal-to-crystal transformation and luminescence change were observed for complex 1 upon solvent exchange, which can be regarded as a potential luminescent sensor for selective detection of water and methanol. [ABSTRACT FROM AUTHOR]

Solvothermal reactions of Cd(II) salts and naphthalene-1,4-dicarboxylic acid (1,4-H2NDC) with bis(N-pyrid-3-ylmethyl)adipoamide, L1, and bis(N-pyrid-3-ylmethyl)suberoamide, L2, afforded three Cd(II) coordination polymers, {[Cd(L1)(1,4-NDC)(H2O)]·H2O}n, 1, {[Cd(L2)(1,4-NDC)]·2H2O}n, 2, and {[Cd2(L2)(1,4-NDC)2]·3H2O}n, 3, which have been structurally characterized using single-crystal X-ray crystallography. Complex 1 forms a 2D layer with 44-sql topology, whereas 2 and 3 are 3D frameworks with rare {32·62·72}{32·65·73}2-4,5T61 and unique {32·54}{34·46·58·66·74}-sqc776 topologies, respectively. Complex 2 undergoes reversible crystal-to-crystal transformation to 3, while irreversible structural transformations from 1 to 2 and 3 to 1 can be carried out by linker exchange. Reorientation of the amide oxygen atoms that results in the change of the ligand conformation is proposed for the initiation of the crystal-to-crystal transformation. Complex 3 represents a unique example of a coordination polymer that is able to undergo both crystal-to-crystal transformation and linker exchange. [ABSTRACT FROM AUTHOR]

Nine 4,4′,4′′,4′′′-(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate derivative electrochromic materials have been designed, synthesized, and characterized. Seven compounds displayed dual-colored electrochromism. The required potential and colored states were markedly influenced by substitution. When the substituent was alkyl, colored states of purple and blue were obtained at an applied voltage of −2.3 and −2.6 V, respectively; when the substituent was phenyl with an electron-donating group, colored states of purple bluish and bright blue were obtained at an applied voltage of −2.1 and −2.3 V, respectively; when the substituent was phenyl with an electron-withdrawing group, monocolored state and bad electrochromic properties were obtained. Moreover, electrochromic devices based on most of these compounds show large optical contrast, fast response time, and high coloration efficiency. [ABSTRACT FROM AUTHOR]

Solvothermal reactions of HgX2 salts with the new bis-pyridyl-bis-amide ligand 2,2′-(1,3-phenylene)-bis(N-(pyridin-3-yl)acetamide) (1,3-pbpa) in acetonitrile afforded the complexes [Hg(1,3-pbpa)X2]n (X = Cl, 1; Br, 2; I, 3), while the complexes [Hg(1,3-pbpa)X2·MeCN]n (X = Br, 4; I, 5) were obtained by layering solutions of HgX2 and 1,3-pbpa at room temperature. Complexes 1 and 2 are isostructural one-dimensional (1D) helical chains different from the 1D helical chain 3 in spans, which are 18.0, 18.3 and 29.1 Å, respectively. Upon solvent adoption and removal, complexes 2 and 3 undergo reversible structural transformation into the 1D mesohelical chains 4 and 5 with spans of 29.1 and 29.9 Å, respectively. Pyridyl ring rotation and amide group reorientation are proposed for the structural transformation accompanied by a simultaneous change in luminescence. The structural transformation in 2 and 4 represents a unique example of elastic 1D helical chains that show stretching during the process. The roles of halide anions in the structural changes and the luminescence properties of 1–5 are also discussed. [ABSTRACT FROM AUTHOR]

The lithium κ1-enamides, Me2NSiMe2CHC(Ph)-{2,6-(R1)2-4-(R2)C6H2}NLi·3THF (R1 = iPr, R2 = H L1; R1 = Et, R2 = H L2; R1 = Me, R2 = H L3; R1 = R2 = Me L4; R1 = Et, R2 = Me L5), in the presence of titanium tetrachloride, undergo intermolecular rearrangement cyclization reactions resulting in 1,3-migration of the silicon groups and the elimination of dimethylamine affording five examples of bis-azasilicon-bridged heterocyclic arylamines, [{2,6-(R1)2-4-(R2)C6H2}N(Ph)CCSiMe2]2 (R1 = iPr, R2 = H D1; R1 = Et, R2 = H D2; R1 = Me, R2 = H D3; R1 = R2 = Me D4; R1 = Et, R2 = Me D5) in good yield, respectively. The molecular structures of D1–D5 show the two fused N–Si–C–C–C rings to be co-planar indicative of extended π-conjugation, while their photophysical properties reveal them to be green/blue emitting with high luminescence quantum yields (ΦF range: 75–99%). Furthermore, the compounds D serve as versatile reactants undergoing ring opening on hydrolysis to afford the saturated 1,4-diimines [{2,6-(R1)2-4-(R2)C6H2}N(Ph)C-CH2]2 (R1 = iPr, R2 = H E1; R1 = Et, R2 = H E2; R1 = Me, R2 = H E3; R1 = R2 = Me E4; R1 = Et, R2 = Me E5). Alternatively, D can be employed in a redox-promoted cascade reaction to afford the conjugated 1,4-diimines, (E)-[{2,6-(R1)2-4-(R2)C6H2}N=C(Ph)CH]2 (R1 = iPr, R2 = H F1; R1 = Et, R2 = H F2; R1 = Me, R2 = H F3; R1 = R2 = Me F4; R1 = Et, R2 = Me F5). In addition to D1–D5, E1–E3, E5, F2 and F3 have been the subject of single crystal X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Two dendritic organic–inorganic hybrid nanomaterials with eight silole units covalently bonded to a POSS core were prepared via a one-step hydrosilylation reaction. These hybrid nanomaterials exhibited aggregation-enhanced emission phenomenon, and displayed outstanding thermal stability and high fluorescence quantum yield. The emissions of these nanoaggregates were selectively quenched by 2,4,6-trinitrophenol. The high selectivity of the sensors was attributed to the combined effects of electron and energy transfer processes. These novel hybrid nanomaterials have the potential to prepare sensitive, selective, and stable sensors for the detection of explosives in aqueous media. [ABSTRACT FROM AUTHOR]

The one-pot solvothermal reactions of 3- and 4-(aminomethyl)pyridine with triethyl orthoformate and Cu(O2CCH3)2 in methanol saturated with dinitrogen afforded the first examples of coordination polymers that are supported by dinitrogen, namely [Cu2.5(3-mpyf)(N2)1.5]n [3-Hmpyf = N,N′-bis(pyridine-3-ylmethyl)formamidine], 1, and {[Cu3(4-Hmpyf)(N2)3]·(CH3OH)}n [4-Hmpyf = N,N′-bis(pyridine-4-ylmethyl)formamidine], 2. The dinitrogen anions of 1 adopt the end-on-dinuclear (μ-η1:η1) bonding mode, resulting in a 4,4-connected binodal net with the new (53·73)2(54·82) topology, and those of 2 display both end-on-dinuclear and end-on-trinuclear (μ-η1:η1:η1) bonding modes, forming a 3,8-connected binodal net with the rare (53)4(58·64·78·84·94)2-3,8T16 topology. [ABSTRACT FROM AUTHOR]

The synthesis, structures and properties of six coordination networks based on N,N′-di(4-pyridyl)suberoamide (L) and angular dicarboxylate ligands, {[Co(L)(MBA)]·2H2O}n (H2MBA = diphenylmethane-4,4′-dicarboxylic acid), 1, {[Co(L)0.5(MBA)]·CH3OH}n, 2, [Co(L)0.5(MBA)]n, 3, {[Co2(L)(OBA)2]·7CH3OH}n [H2OBA = 4,4′-oxybis(benzoic acid)], 4, {[Co(L)(hfipbb)]·2H2O}n [H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)], 5, and {[Co(L)(SDA)]·H2O}n (H2SDA = 4,4′-sulfonyldibenzoic acid), 6, are reported. Complex 1 is a 1D → 2D polycatenane derived from the helical channels, whereas both complexes 2 and 3 show 2D layers with the (42·68·8·104)(4)2-2,6L1 topology, which are further entangled to form a 2-fold 2D → 2D interpenetration network and a 2D → 3D inclined polycatenation network, respectively, and complex 4 shows a 3-fold 3D → 3D interpenetration network with the (412·63)-pcu topology. The unusual topological features of 5 and 6 consist of 2- and 3-fold interpenetrated layers with the (44·62)-sql topology, which are further catenated to the two such adjacent sheets in parallel and uniform fashions to give 2D → 3D polycatenated networks. Complexes 1, 5 and 6 represent unique examples that the angular dicarboxylate ligands show significant effect on the degree of interpenetration of polycatenation coordination networks with interpenetrating modes. The CO2 capture is preferable to N2 and H2 in the gas sorption for the desolvated product of 4. [ABSTRACT FROM AUTHOR]

Novel electrochromic and photoresponsive materials based on azobenzene-4,4′-dicarboxylic acid dialkyl ester derivatives (ADDEDs) were successfully prepared and characterized through nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and high-performance liquid chromatography-mass spectrometry. The electrochromic behavior, electrochromic mechanism, electro-optical properties, and photoresponsive properties of ADDEDs were investigated through cyclic voltammetry and ultraviolet-visible absorption spectra. ADDEDs displayed not only outstanding electrochromic behavior but also good and reversible photoisomerization properties even under electrochromic conditions. Electrochromic devices (ECDs) based on ADDEDs were fabricated, and their electrochromic performance was analyzed. The ECDs presented a color change from colorless to magenta between 0.0 V (bleached state) and ±3.0 V (colored state). In addition, the ECDs exhibited fast switching times, reasonable contrast, satisfactory optical memories, and redox stability. The novel redox-active azobenzene derivatives are promising candidates for full-color EC display devices, electronic paper, smart windows, optical memory devices, dual-stimuli-responsive systems, as well as other potential new applications. [ABSTRACT FROM AUTHOR]

Graphene has attracted increasing attention in different scientific fields including catalysis. Via modification with foreign metal-free elements such as nitrogen, its unique electronic and spin structure can be changed and these doped graphene sheets have been successfully employed in some catalytic reactions recently, showing them to be promising catalysts for a wide range of reactions. In this review, we summarize the recent advancements of these new and interesting catalysts, with an emphasis on the universal origin of their catalytic mechanisms. We are full of hope for future developments, such as more precisely controlled doping methods, atom-scale surface characterization technology, generating more active catalysts via doping, and finding wide applications in many different fields. [ABSTRACT FROM AUTHOR]

Hydrothermally treated graphene oxide was found to be a new metal-free catalyst for reduction from 4-nitrophenol to 4-aminophenol. Based on the combined experimental and theoretical investigations, hydroxyl and alkoxy radicals, as well as holes were found beneficial to the catalytic performance, while epoxy and carboxyl groups were unfavorable and should be avoided in practical applications. [ABSTRACT FROM AUTHOR]

The Fe3O4@C core-shell magnetic nanoparticles with an average size of about 190 nm were synthesized via a one-pot solvothermal process using ferrocene as a single reactant. The sulfonic acid-functionalized Fe3O4@C magnetic nanoparticles were obtained by grafting the sulfonic groups on the surface of Fe3O4@C nanoparticles to produce magnetically recyclable solid acid catalysts. The as-prepared products were characterized by X-ray diffraction and transmission electron microscopy. The catalytic performance of the as-prepared catalysts was examined through the condensation reaction of benzaldehyde and ethylene glycol. The results showed that the catalysts exhibited high catalytic activity with a conversion rate of 88.3% under mild conditions. Furthermore, catalysts with a magnetization saturation of 53.5 emu g-1 at room temperature were easily separated from the reaction mixture by using a 0.2 T permanent magnet and were reused 8 times without any significant decrease in catalytic activity. [ABSTRACT FROM AUTHOR]

The performance of N-doped graphene on Li-ion battery has been investigated systematically by means of a density functional theory method. Pyridinic N doping, graphitic N atoms and 5-8-5 double vacancies have been selected as the functional defects to study their influence on Li storage compared to the pristine graphene. It has been confirmed that introducing pyridinic N atoms with p-type doping is a suitable method, especially for graphene doped with 4 pyridinic N atoms, whose structural distortion induced by Li intercalation is small and supplies strong force for Li adsorption. The diffusion barrier for this model is lower than for pristine graphene, both for the side and center diffusion routes, contributing to the high mobility. In addition, we point out that the strong catch force for Li will cause more Li to stay on the pyridinic N-doped graphene during the charge–discharge cycles, leading to a faster decrease of capacity compared to pristine graphene. [ABSTRACT FROM AUTHOR]

Nearly monodispersed yolk-type Au@Fe3O4@C nanospheres with hollow cores of 50 nm in diameter were prepared through coating Au@SiO2 nanoparticles with Fe3O4@C double layers, followed by dissolving SiO2. The cytotoxicity of the nanospheres was evaluated by MTT assay, demonstrating a high biocompatibility. The yolk-type nanospheres show a high DOX loading content of 1237 mg g−1. The coexistence of Fe3O4 and Au also makes the nanospheres as dual probes for MR imaging with a specific relaxivity (r2*) of 384.38 mM−1 s−1 and optical fluorescence imaging using a near-infrared (NIR) excitation. [ABSTRACT FROM AUTHOR]

A catalytic intermolecular carbon electrophile induced semipinacol rearrangement was realized and the asymmetric version was also preliminarily accomplished with 92% and 82% ee. The complex tricyclic system architecture with four continuous stereogenic centers could be achieved from simple starting materials in a single step under mild conditions. [ABSTRACT FROM AUTHOR]

A six-membered N-heterocyclic carbene fused with a spiro-scaffold is designed. The new NHC shows stronger σ-donation ability than typical 5-membered NHCs. This property leads to interesting reactivities of this spiro-fused six-membered NHC. For example, the NHC-BF3 Lewis pair complex can be readily prepared by using LiBF4 as the BF3 source, or through a direct bond-reconstruction of the tetrafluoroborate salt NHC·HBF4.

The Fe3O4@C core-shell magnetic nanoparticles with an average size of about 190 nm were synthesized via a one-pot solvothermal process using ferrocene as a single reactant. The sulfonic acid-functionalized Fe3O4@C magnetic nanoparticles were obtained by grafting the sulfonic groups on the surface of Fe3O4@C nanoparticles to produce magnetically recyclable solid acid catalysts. The as-prepared products were characterized by X-ray diffraction and transmission electron microscopy. The catalytic performance of the as-prepared catalysts was examined through the condensation reaction of benzaldehyde and ethylene glycol. The results showed that the catalysts exhibited high catalytic activity with a conversion rate of 88.3% under mild conditions. Furthermore, catalysts with a magnetization saturation of 53.5 emu g(-1) at room temperature were easily separated from the reaction mixture by using a 0.2 T permanent magnet and were reused 8 times without any significant decrease in catalytic activity.

Nearly monodispersed yolk-type Au@Fe3O4@C nanospheres with hollow cores of 50 nm in diameter were prepared through coating Au@SiO2 nanoparticles with Fe3O4@C double layers, followed by dissolving SiO2. The cytotoxicity of the nanospheres was evaluated by MTT assay, demonstrating a high biocompatibility. The yolk-type nanospheres show a high DOX loading content of 1237 mg g(-1). The coexistence of Fe3O4 and Au also makes the nanospheres as dual probes for MR imaging with a specific relaxivity (r2*) of 384.38 mM(-1) s(-1) and optical fluorescence imaging using a near-infrared (NIR) excitation.

Porous Fe(3)O(4)@C nanocapsules with a diameter of about 120 nm (about 50 nm cavity) were synthesized by combining a sacrificial template method with solvothermal treatment. The N(2) adsorption-desorption isotherms reveals their mesoporous structure and large BET surface area (159.8 m(2) g(-1)). The magnetic investigation indicates their superparamagnetic nature and high saturation magnetization (55.93 emu g(-1)). The nanocapsules also exhibit negative zeta potential (-27.59 mV) and possess carboxyl groups on the outer carbon layer, which keeps them highly dispersive in aqueous solution and provides a chelating function for metal ions. The heavy metals removal test demonstrates the excellent affinity of nanocapsules, the high efficiency for different metals (>90%), 79 mg g(-1) adsorption capacity for Pb(2+) and ultrafast removal process (Pb(2+), 99.57% within 1 minute). Protected by a porous carbon layer, the nanocapsules display excellent acidic resistance and adsorption properties even in an acidic solution (pH = 3). Moreover, the metal ions can be easily adsorbed and desorbed through manipulating the pH value for adsorbent regeneration and heavy metal recycling.