Regulation of Nontraditional Intrinsic Luminescence (NTIL) in Hyperbranched Polysiloxanes by Adjusting Alkane Chain Lengths: Mechanism, Film Fabrication, and Chemical Sensing.

Biocompatible polymers with nontraditional intrinsic luminescence (NTIL) possess the advantages of environmental friendliness and facile structural regulation. To regulate the emission wavelength of polymers with NTIL, the alkane chain lengths of hyperbranched polysiloxane (HBPSi) are adjusted. Optical investigation shows that the emission wavelength of HBPSi is closely related to the alkane chain lengths; namely, short alkane chains will generate relatively long-wavelength emission. Electronic communication among functional groups is responsible for the emission. In a concentrated solution, HBPSi molecules aggregate together due to the strong hydrogen bond and amphiphilicity, and the functional groups in the aggregate are so close that their electron clouds are overlapped and generate spatial electronic delocalizations. HBPSi with shorter alkane chains will generate larger electronic delocalizations and emit longer-wavelength emissions. Moreover, these polymers show excellent applications in the fabrication of fluorescent films and chemical sensing. This work could provide a strategy for regulating the emission wavelengths of unconventional fluorescent polymers.

Combination of Mn-Mo Oxide Nanoparticles on Carbon Nanotubes through Nitrogen Doping to Catalyze Oxygen Reduction.

An efficient and low-cost oxygen catalyst for the oxygen reduction reaction (ORR) was developed by in situ growth of Mn-Mo oxide nanoparticles on nitrogen-doped carbon nanotubes (NCNTs). Doped nitrogen effectively increases the electron conductivity of the MnMoO4@NCNT complex and the binding energy between the Mn-Mo oxide nanoparticles and carbon nanotubes (CNTs), leading to fast charge transfer and more catalytically active sites. Combining Mn and Mo with NCNTs improves the catalytic activity and promotes both electron and mass transfers, greatly enhancing the catalytic ability for ORR. As a result, MnMoO4@NCNT exhibited a comparable half-wave potential to commercial Pt/C and superior durability, demonstrating great potential for application in renewable energy conversion systems.

Nitrogen-Doped and Surface Functionalized CDs: Fluorescent Probe for Cellular Imaging and Environmental Sensing of ClO.

A novel nitrogen doped and surface functionalized fluorescent CDs (T1) was synthesized by one-step and green hydrothermal method, which exhibits a satisfactory fluorescence quantum yield and a series of admirable features such as good aqueous solubility, narrow particle size distribution, resistance to photobleaching as well as excitation-dependent behavior. Benefitting from above merits, T1 can be employed to serve as an outstanding sensing platform for sensitive and accurate detection of ClO- by remarkable fluorescence "on-off" process with rapid and anti-interference. More notably, the good biocompatibility and photostability can ensure enormous bioimaging potential and successful application of T1 in monitoring of exogenous ClO- in MG-63 cells. Meanwhile, T1 can also be regarded as a filter paper sensor providing a convenient and efficient analyzing technology for monitoring of free residual chlorine in practical environmental samples. All these results demonstrate that there exists promising possibility for practical applications of T1 in bioimaging systems and environmental monitoring.

Heterobinuclear Zn-Ln (Ln = La, Nd, Eu, Gd, Tb, Er and Yb) complexes based on asymmetric Schiff-base ligand: synthesis, characterization and photophysical properties.

With a novel asymmetric Schiff-base zinc complex ZnL (H2 L = N-(3-methoxysalicylidene)-N'-(5-bromo-3-methoxysalicylidene)phenylene-1,2-diamine), obtained from phenylene-1,2-diamine, 3-methoxysalicylaldehyde and 5-bromo-3-methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn-Ln complexes [ZnLnL(NO3 )3 (CH3 CN)] (Ln = La, 1; Ln = Nd, 2; Ln = Eu, 3; Ln = Gd, 4; Ln = Tb, 5; Ln = Er, 6; Ln = Yb, 7) were synthesized by the further reaction with Ln(NO3 )3 ·6H2 O, and characterized by Fourier transform-infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near-infrared luminescence of Nd(3+) , Yb(3+) and Er(3+) with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff-base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions.

Nitrogen-doped hierarchical porous carbons derived from biomass for oxygen reduction reaction.

Nowadays biomass has become important sources for the synthesis of different carbon nanomaterials due to their low cost, easy accessibility, large quantity, and rapid regeneration properties. Although researchers have made great effort to convert different biomass into carbons for oxygen reduction reaction (ORR), few of these materials demonstrated good electrocatalytical performance in acidic medium. In this work, fresh daikon was selected as the precursor to synthesize three dimensional (3D) nitrogen doped carbons with hierarchical porous architecture by simple annealing treatment and NH3 activation. The daikon-derived material Daikon-NH3-900 exhibits excellent electrocatalytical performance towards oxygen reduction reaction in both alkaline and acidic medium. Besides, it also shows good durability, CO and methanol tolerance in different electrolytes. Daikon-NH3-900 was further applied as the cathode catalyst for proton exchange membrane (PEM) fuel cell and shows promising performance with a peak power density up to 245 W/g.

Influences of Four Kinds of Surfactants on Biodegradations of Tar-Rich Coal in the Ordos Basin by Bacillus bicheniformis.

The biodegradation of tar-rich coal in the Ordos Basin was carried out by Bacillus licheniformis (B. licheniformis) under actions of four kinds of surfactants, namely, a biological surfactant (Rh), a nonionic surfactant (Triton X-100), an anionic surfactant (LAS), and a cationic surfactant (DTAB). The biodegradation rates under the actions of Triton X-100, LAS, Rh, DTAB, and the control group (without surfactant) were 59.8%, 54.3%, 51.6%, 17.3%, and 43.5%, respectively. The biodegradation mechanism was studied by examining the influences of surfactants on coal samples, bacteria, and degradation products in the degradation process. The results demonstrated that Rh, Triton X-100, and LAS could promote bacterial growth, while DTAB had the opposite effect. Four surfactants all increased the cell surface hydrophobicity (CSH) of B. licheniformis, and Triton X-100 demonstrated the most significant promotion of CSH. The order of improvement in microbial cell permeability by surfactants was DTAB > TritonX-100 > LAS > Rh > control group. In the presence of four surfactants, Triton X-100 exhibited the best hydrophilicity improvement for oxidized coal. Overall, among the four surfactants, Triton X-100 ranked first in enhancing the CSH of bacteria and the hydrophilicity of oxidized coal and second in improving microbial cell permeability; thus, Triton X-100 was the most suitable surfactant for promoting B. licheniformis's biodegradation of tar-rich coal. The GC-MS showed that, after the action of Triton X-100, the amount of the identified degradation compounds in the toluene extract of the liquid product decreased by 16 compared to the control group, the amount of dichloromethane extract decreased by 6, and the amount of ethyl acetate extract increased by 6. Simultaneously, the contents of alkanes in the extracts of toluene and dichloromethane decreased, lipids increased, and ethyl acetate extract exhibited little change. The FTIR analysis of the coal sample suggested that, under the action of Triton X-100, compared to oxidized coal, the Har/H and A(CH2)/A(CH3) of the remaining coal decreased by 0.07 and 1.38, respectively, indicating that Triton X-100 enhanced the degradation of aromatic and aliphatic structures of oxidized coal. Therefore, adding a suitable surfactant can promote the biodegradation of tar-rich coal and enrich its degradation product.

4-Bromo-2-meth-oxy-6-(1-phenyl-1H-benzimidazol-2-yl)phenol.

The title compound, C(20)H(15)BrN(2)O(2), crystallized with three independent molecules in the asymmetric unit. Intramolecular O-H⋯N hydrogen bonds induce coplanarity of the substituted benzene ring and the benzimidazole ring, with mean deviations from the planes of 0.0931 (10), 0.0448 (10) and 0.0083 (11) Šin the three mol-ecules.

{6,6'-Dimeth-oxy-2,2'-[cyclo-hexane-1,2-diylbis(nitrilo-methanylyl-idene)]diphenolato}copper(II) monohydrate.

In the title compound, [Cu(C22H24N2O4)]·H2O, the Cu(II) atom is four-coordinated in a distorted planar geometry with a mean deviation of 0.1164 (2) Šfor the plane generated by the ligating atoms of the salen-type Schiff base ligand. In the crystal, O(water)-H⋯O and C-H⋯O hydrogen bonds form a three-dimensional-network.

(Z)-4-[(2-Amino-4,5-dichloro-anilino)(phenyl)methyl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

The mol-ecule of the title compound, C(23)H(18)Cl(2)N(4)O, assumes a non-planar conformation in which the pyrazolone ring forms dihedral angles of 32.61 (19), 76.73 (14) and 52.57 (19)° with the three benzene rings. The secondary amino group is involved in an intra-molecular N-H⋯O hydrogen bond. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers. An offset stacking inter-action is observed between the chloro-substituted benzene rings protruding on both sides of these dimers [centroid-centroid distance = 3.862 (1) Å].

(E)-2-[(2-Amino-phen-yl)imino-meth-yl]-4,6-di-tert-butyl-phenol.

In the title compound, C(21)H(28)N(2)O, the dihedral angle between the rings is 35.2 (2)°. A weak intra-molecular O-H⋯N hydrogen bond is observed between the O-H H atom and the imine N atom. In the crystal, mol-ecules are linked by additional inter-molecular N-H⋯O hydrogen bonding, resulting in a wave-like chain along the b-axis direction.

{2,2'-[Cyclo-hexane-1,2-diylbis(nitrilo-methanyl-ylidene)]diphenolato}copper(II).

The title compound, [Cu(C(20)H(20)N(2)O(2))], crystallizes with two independent mol-ecules in the asymmetric unit. In each mol-ecule, the Cu(II) atom occupies the tetra-dentate N(2)O(2) cavity of the salen-type Schiff base ligand, adopting a distorted square-planar geometry with r.m.s. deviations of the coordin-ating atoms of 0.0522 (2) and 0.1128 (4) Å. No hydrogen bonds or π-π stacking inter-action are observed.

(Z)-4-[(3-Aminona-phthalen-2-yl-amino)(phen-yl)methyl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

The mol-ecule of the title compound, C(27)H(22)N(4)O, assumes a non-planar conformation in which the pyrazolone ring forms dihedral angles of 12.73 (11), 65.17 (6) and 49.82 (6)°, respectively, with the two benzene rings and the naphthalene ring system. In the crystal, pairs of mol-ecules are linked by inter-molecular N-H⋯N hydrogen bonds, forming dimers. The secondary amino group is involved in an intra-molecular N-H⋯O hydrogen bond.

(E)-N'-(5-Bromo-2-hy-droxy-3-meth-oxy-benzyl-idene)-2-hy-droxy-benzohydrazide monohydrate.

The organic molecule of the title hydrate, C(15)H(13)BrN(2)O(4)·H(2)O, is roughly planar, with a mean deviation of 0.0939 (2) Å. The dihedral angle between the two aromatic rings is 8.2 (3)°. Intra-molecular O-H⋯N and O-H⋯O hydrogen bonds are observed. In the crystal, N-H⋯O(water) and O(water)-H⋯O hydrogen bonds lead to a three-dimensional network.

Bis[µ-N'-(5-bromo-3-meth-oxy-2-oxido-benzyl-idene)-2-hydroxybenzohydra-zidato]bis[(N,N-dimethyl-formamide)-copper(II)].

The title compound, [Cu(2)(C(15)H(11)BrN(2)O(4))(2)(C(3)H(7)NO)(2)], is derived from the reaction of N'-(5-bromo-2-hy-droxy-3-meth-oxy-benzyl-idene)-2-hy-droxy-benzohydrazide and copper nitrate in a dimethyl-formamide solution in the presence of sodium hydroxide. The compound can be regarded as a binuclear centrosymmetric complex. In the crystal, the Cu(II) atom is fivefold surrounded and adopts a distorted square-pyramidal coordination environment. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation.

Three water-soluble acylhydrazone tetranuclear transition metal complexes: Crystal structures, DNA/BSA interactions and cytotoxicity studies.

2-acetylpyridine-4-chloropyridine-2­carbonyl hydrazone (C13H11ClN4O, HL) and its three water-soluble tetranuclear complexes [Cu4(NO3)2(L)4]·(NO3)2 (1), [Co4(NO3)2(H2O)(C2H5OH)(L)4]·(NO3)2 (2) and [Zn4(NO3)2(H2O)(C2H5OH)(L)4]·(NO3)2 (3) were synthesized and characterized showing that 1-3 were all tetranuclear complexes. The interactions of HL, 1-3 with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) were explored using ultraviolet-visible (UV-Vis) titration, fluorescence spectroscopy, microcalorimetry and molecular docking techniques. The UV-Vis spectroscopy measurements showed that complexes 1-3 could strongly bind to CT-DNA by the intercalation mode, while HL interacted with CT-DNA through groove binding. From the fluorescence spectroscopy results, the interaction between HL, 1-3 and BSA was a static quenching procedure, in which complexes 1-3 had two binding sites near Trp residues of BSA while HL only had one. The microcalorimetric studies revealed that the interactions of HL and 1-3 to CT-DNA/BSA were all endothermic and the duration of each interaction was all less than 30 min. The in silico molecular docking illustrated intermolecular interactions of 1-3 binding with DNA/BSA included hydrogen bond, halogen bond, hydrophobic and electrostatic interactions. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that complex 1 possessed better cytotoxicity against HeLa, A549, MCF7 and HCT-116 than cisplatin and could be used as an alternative anticancer drug.

Nitrogen-doped carbon quantum dots as fluorescent nanosensor for selective determination and cellular imaging of ClO.

The carbon nanomaterial based fluorescent probes have been widely applied in biological imaging. In the current research, we propose an interesting strategy for selective sensing of hypochlorite (ClO-) by a water-soluble and highly fluorescent nanosensor based on the N-doped carbon quantum dots (CDs) which was fabricated by a facile and environmental friendly hydrothermal approach from polyvinyl pyrrolidone, L-arginine and tryptophan. The structural characteristics of the probe were measured by multitudinous methods which proved the nanometer spherical structure of the probe and the successfully N-doping. Fluorescent investigation demonstrated that the probe is not only highly stable under interferences of pH, ionic strength, and irradiation, but also significantly selective toward ClO- amongst a variety of attractive bioactive species through the fluorescent quenching process which was correlative with the concentration of ClO- and linearly in the range of 0.1-50 µmol·L-1 with the sensitivity of 0.03 µmol·L-1. The probe can also be further illustrated in a prospective application for determination of ClO- in environmental water through both solution response and filer paper sensing. Moreover, the positive biocompatibility and ignorable cytotoxicity made the probe a promising effective agent for detection and visualizing ClO- in living cells which can facilitate the understanding the oxidative stress from the overexpressing ClO-.

2-{[2-(2-Hy-droxy-3-meth-oxy-benzyl-idene)hydrazin-1-yl-idene]meth-yl}-6-meth-oxy-phenol.

The title compound, C(16)H(16)N(2)O(4), was obtained from the reaction of hydrazine hydrate and o-vanilin in absolute ethanol. The mol-ecule is almost planar (except for the methyl H atoms), with a mean deviation from the plane of 0.0259 Å. The mol-ecular structure also exhibits an approximate non-crystallographic twofold axis. Intra-molecular O-H⋯N hydrogen bonds occur. In the crystal, inter-molecular C-H⋯O hydrogen bonds generate mol-ecular zigzag sheets. The sheets stack through C-H⋯π inter-actions, leading to a three-dimensional-network.

(Z)-4-[(2-Amino-anilino)(phen-yl)methyl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

The mol-ecule of the title compound, C(23)H(20)N(4)O, assumes a non-planar conformation in which the pyrazolone ring forms dihedral angles of 10.33 (11), 65.34 (11) and 63.52 (10)° with the three benzene rings. In the crystal, the mol-ecules are linked by inter-molecular N-H⋯N hydrogen bonds, generating chains parallel to the b axis. The secondary amino group is involved in an intra-molecular N-H⋯O hydrogen bond.

1H-Pyrrole-2-carbohydrazide.

The title compound, C(5)H(7)N(3)O, was obtained by the reaction of ethyl 1H-pyrrol-2-carboxyl-ate and hydrazide hydrate. In the crystal, mol-ecules are linked via inter-molecular N-H⋯N and N-H⋯O hydrogen bonds, forming a supra-molecular grid.

Study of the Influence of Biodegradation on Coal Micro-Nano Pore Structure Using Low-Temperature N2 Adsorption.

An experimental study of biodegradation of Shenmu coal was carried out by using Ochrobactrum cytisi, Novospingobium naphthalenivorans, Alcaligenes faecalis and Pseudomonas fluorescens. The micro-nano pore structure of coal samples before and after biodegradation was studied by low-temperature N2 adsorption. For biodegraded coal, the results showed that micropores and mesopores are primarily open pores with good connectivity, including parallel plate pores and cylinder pores with two open ends; the specific surface area of biodegraded coal decreased from 2.2174 m²/g to 1.6255˜2.0537 m²/g, and the pore size of the coal biodegraded by the four bacteria decreased following biodegradation from 250 nm to 170˜200 nm, which may be due to collapse of the coal structure due to the bacterial degradation. Coal biodegradation by the dominant bacterium P. fluorescens led to a diminished mesopore size and an increased number of smaller mesopores, with the smaller mesopores gradually taking on dominant roles.