Coherent kinetic control over crystal orientation in macroscopic ensembles of polymer nanorods and nanotubes

We show that the crystal orientation in polymer nanotubes and nanorods inside porous templates is controlled by the kinetics of nucleation and growth under 2D confinement. Two clear limiting cases are identified: In separated nanostructures, any crystal orientation allowing the growth of lamellar crystals along the pores appears statistically. If a bulklike surface film connects the nanostructures, macroscopic arrays with uniform crystal orientation are obtained, in which the dominant growth direction of the crystals is aligned with the long axes of the pores of the template.     

Quantum chemical investigation on D-π-A-based phenothiazine organic chromophores with spacer and electron acceptor effects for DSSCs

Structural Chemistry - In this work, the newly designed phenothiazine-based organic dye (PT-BTBA, PT-EBTBA, and PT-EBTEBA) derivatives were screened and investigated for dye-sensitized solar cell...     

Near‐infrared Raman spectroscopic characterization of salivary metabolites in the discrimination of normal from oral premalignant and malignant conditions

In the present study, Raman spectroscopy has been employed in the discrimination of the saliva of normal subjects from patients with oral submucous fibrosis and oral squamous cell carcinomaat 785‐nm excitation. From the spectral signatures, prominent difference between normal and abnormal group because of variations in metabolic and pathological conditions of the subjects was observed. Principal component analysis coupled with linear discriminant analysis yielded a diagnostic sensitivity of 96.4 and 93.8% and a specificity of 70.2 and 95.7% in the classification of normal from premalignant and normal from malignant, respectively, confirming the efficacy of Raman spectroscopy in the classification of normal and oral abnormalities. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis,Spectral Characterization and Solvent Effects on the Electro-Reduction of Mixed Ligand Cobalt(III) Complexes

A series of cobalt(III) complexes of the type cis-β-[Co(ampy)₂(4-R-Py)Cl]Cl₂ where ampy = 2-aminomethylpyridine, R = H, Me, Et, t-Bu, COMe, and CN has been synthesized and characterized spectroscopically. The electro-reduction of these complexes has been studied in propan-2-ol/water and 1,4-dioxane/water media. The redox potential (E _1/2) data were correlated with solvent and structural parameters with an aim to shed some light on the mechanism of these reactions. Correlation of E _1/2 with macroscopic solvent parameters viz. relative permittivity, indicates that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The Kamlet-Taft solvatochromic comparison method was used to separate and quantify the specific and non-specific solvent effects on the redox process. Increases in the percentage of organic co-solvent in both media makes the electro-reduction of Co(III) to Co(II) easier.     

Metal complexes of N-benzamidoporphyrin: (N-benzimido-meso-tetraphenylporphyrinato)(methanol)zinc(II) methanol solvate and (acetato)(N-benzamido-meso-tetraphenylporphyrinato)cadmium(II) benzene solvate

The crystal structures of N-benzamido-meso-tetraphenylporphyrin (NHCOC(6)H(5)-Htpp; 1), (N-benzimido-meso-tetraphenylporphyrinato)(methanol)zinc(II) [Zn(N-NCOC(6)H(5)-tpp)(MeOH); 2(MeOH)], and (acetato)(N-benzamido-meso-tetraphenylporphyrinato)cadmium(II) [Cd(N-NHCOC(6)H(5)-tpp)(OAc); 3] were established. The coordination sphere around Zn(2+) ion in 2(MeOH) is a distorted trigonal bipyramid with N(2), N(5), and O(2) lying in the equatorial plane, whereas, for Cd(2+) ion in 3, it is a sitting-atop derivative with a distorted trigonal bipyramidal geometry in which the apical site is occupied by atoms N(2) and O(2). Cd in 3 acquires five-coordination with five strong bonds [Cd(1)-N(1) = 2.319(5) A, Cd(1)-N(2) = 2.252(5) A, Cd(1)-N(3) = 2.332(5) A, Cd(1)-O(2) = 2.292(5) A, and Cd(1)-O(3) = 2.317(5) A] and with one secondary intramolecular interaction [Cd(1)...N(4)]. The porphyrin ring in these two complexes is distorted to a large extent. The plane of the three pyrrole nitrogen atoms [i.e., N(1)-N(3)] strongly bonded to Zn(2+) in 2(MeOH) and to Cd(2+) in 3 is adopted as a reference plane 3N. For the Zn(2+) complex, the pyrrole nitrogen bonded to the benzamido (BA) ligand lies in a plane with a dihedral angle of 33.8 degrees with respect to the 3N plane, but for the Cd(2+) complex, this dihedral angle is found to be 31.4 degrees. In the former complex, Zn(2+) and N(5) are located on the different side at -0.08 and 1.39 A from its 3N plane, and in the latter one, Cd(2+) and N(5) are also located on the different side at 1.08 and -1.51 A from its 3N plane. VT NMR ((1)H and (13)C) studies of 3 show that the acetate acts as a bidentate ligand and the OAc(-) exchange does not occur in CD(2)Cl(2). Moreover, the NH proton [i.e., H(5)] of 3 in CD(2)Cl(2) is observed as a sharp singlet at delta = -1.13 ppm with Delta nu(1/2) = 4 Hz at 20 degrees C indicating that the intermolecular proton exchange between water and NH proton is rapid.     

Occurrence of uranium in groundwater of a shallow granitic aquifer and its suitability for domestic use in southern India

Groundwater used for domestic purpose without proper treatment should be free from chemical and biological contaminants. This study was carried out to assess the groundwater quality with respect to uranium in a part of Nalgonda district, Andhra Pradesh, India. Groundwater was regularly monitored for uranium concentration by collection of samples once every two months from March 2008 to November 2009 from 44 wells. The concentration of uranium in groundwater ranged from 0.2 to 118.4 ppb. Groundwater is unsuitable for domestic use in 2 % of this area based on the limit of 60 ppb prescribed by the Atomic Energy Regulatory Board of India. However, due the wide variation in limit suggested by different organizations and countries, the no-observed-adverse-effect level and lowest-observed-adverse-effect level (in mg/kg day) was used to understand the dosage of uranium that reaches the people through drinking water pathway. This level varied from 0 to 0.02 mg/kg day and 0 to 0.08 mg/kg day based on an uncertainty factor of 10 and 50 respectively for the mean uranium concentration in groundwater in each well. With an uncertainty factor of 50, 5 groundwater samples had uranium above 0.06 mg/kg day which is the lowest-observed-adverse-effect level. This study showed that with the presence of present level of uranium concentration in groundwater of this area there is no major threat to humans through the drinking water pathway.     

Preparation of nitrogen-doped reduced graphene oxide and its use in a glassy carbon electrode for sensing 4-nitrophenol at nanomolar levels

We describe a novel procedure for the synthesis of nitrogen-doped reduced graphene oxide (N-rGO). It is based on the thermal reduction of GO (dispersed in water) with sodium diethyldithiocarbamate that acts as both the reducing agent and the source for nitrogen. The surface morphology of the N-rGO is characterized using high resolution transmission electron microscopy. X-ray photoelectron spectroscopy was carried out to study the composition of their surface, and Raman spectroscopy was performed to study the level of doping with nitrogen and the structural order. The N-rGO was deposited on a glassy carbon electrode (GCE), and the resulting electrode utilized as a sensing platform for 4-nitrophenol (4-NP). The modified GCE exhibits a well-defined oxidation peak current that is about ten times larger when compared to that of a bare GCE. The electron transfer number, proton transfer number and electron transfer rate constant (k_s 1.046 s⁻¹) were determined. At optimized conditions, the oxidation peak current is linearly related to the concentration of 4-NP in the 20–500 nM range, with a correlation coefficient of 0.9917. The detection limit (at an SNR of 3) is 7 nM. The method was successfully applied to the analysis of waters spiked with 4-NP. Recoveries range from 97.8 to 102.6 %, and no interferences are found for common inorganic cations and anions.

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Synthesis and spectral characterization of lanthanide complexes with sulfamethoxazole and their antibacterial activity

A series of nonelectrolytic lanthanide(III) complexes, [ML₂Cl₃]·2H₂O, where M is lanthanum(III), praseodymium(III), neodymium(III), samarium(III), gadolinium(III), terbium(III), dysprosium(III), and yttrium(III), containing sulfamethoxazole ligand (L) are prepared. The structure and bonding of the ligand are studied by elemental analysis, magnetic susceptibility measurements, IR, ¹HNMR, TG/DTA, X-ray diffraction studies, and electronic spectra of the complexes. The stereochemistry around the metal ions is a monocapped trigonal prism in which four of the coordination sites are occupied by two each from two chelating ligands, sulfonyl oxygen, and nitrogen of the amide group and the remaining three positions are occupied by three chlorines. The ligand and the new complexes were tested in vitro to evaluate their activity against the bacteria Escherichia coli and Staphylococcus aureus. The text was submitted by the authors in English.     

Spectroscopic studies on the interaction of cilostazole with iodine and 2,3-dichloro-5,6-dicyanobenzoquinone

Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln³⁺). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb³⁺–FQ and Eu³⁺–FQ complexes have been investigated in this contribution. Ce⁴⁺–SO₃²⁻ in acidic conditions was taken as the CL system and sensitized CL intensities of Tb³⁺–FQ and Eu³⁺–FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb³⁺–FQ complexes show characteristic peaks of Tb³⁺ at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb³⁺–ENX, Tb³⁺–NFLX, Tb³⁺–LMFX and Tb³⁺–FLRX display relatively strong emission intensity compared with Tb³⁺–OFLX, Tb³⁺–RFX, Tb³⁺–GFLX and Tb³⁺–SPFX. Quite weak peaks with unique characters of Eu³⁺ at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu³⁺–ENX, but no notable sensitized luminescence and CL of Eu³⁺ could be observed when Eu³⁺ is added into other FQ. The distinct differences on emission intensity of Tb³⁺–FQ and Eu³⁺–FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln³⁺. The different sensitized luminescence and CL signals among Tb³⁺–FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb³⁺–FQ and Eu³⁺–FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results.     

Effect of high temperature on reduction-controlling reaction rate of agricultural waste chars and coke with steelmaking slag

In the present research, mechanical and thermal properties of high-density polyethylene/wood flour were improved by incorporating nanoclay (Cloisite 30B) and antioxidant (Irganox B225) in the compound. Design of experiments was carried out to optimize composition among nine compounds and to investigate the effect of nanoclay and antioxidant (0–5 phr) and (0–0.4 phr), respectively. The results of mechanical tests showed approximately 24% increase in the tensile strength of compounds containing 2.5 and 5.0 part per hundred (phr) of the nanoclay in the composite compared with the same samples without nanoclay. The tensile modulus of composites increased 7.3% by increasing the level of nanoclay from 0 to 2.5 phr. However, a further increase in the nanoclay content led to a 4.3% decrease in tensile modulus. Evaluation of the thermal oxidation stability of samples confirmed that the thermal oxidation of composites decreased with increasing nanoclay from 0 to 5.0 phr and increased significantly with the addition of the antioxidant.