Open Access Published by De Gruyter Open Access

Volume 11 Issue 9

September 2013

Issue of Open Chemistry

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Journal Overview

Open Access June 29, 2013

Synthesis of poly(vinyl alcohol) — hydroxyapatite composites and characterization of their bioactivity

Zuzana Balgová, Martin Palou, Jaromír Wasserbauer, Jana Kozánková

Page range: 1403-1411

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Abstract

Abstract A series of poly(vinyl alcohol) membranes reinforced with hydroxyapatite in various weight percent — 0%, 10%, 20%, 30%, 40% and 50% were prepared. Hydroxyapatite was prepared by a sol-gel procedure using diammonium hydrogen phosphate and calcium nitrate tetrahydrate as starting materials in an alkaline aqueous environment and then mixed with a solution of poly(vinyl alcohol), which was prepared by dissolving it in water at 85°C. The different mixtures were cast in a mould and evaporated for 7 days at a temperature of 30°C to obtain 1 mm thin membranes. FTIR spectroscopy was used to identify the different functional groups in the composites. The surface morphology was examined using a scanning electron microscope. In vitro bioactivity tests in Simulated Blood Fluid were performed for up to 28 days, especially for the membrane containing 50 wt.% HA. SEM was used to characterise the surface microstructure of biocomposite membranes before and after soaking in SBF. It was observed that the formation of clusters in membranes increases with increasing amount of HA. The clusters are formed due to agglomeration and crystal growth of HA particles during drying of the membranes. The in vitro bioactivity was found to increase with soaking time of biocomposite materials in simulated blood fluid. Graphical abstract

Open Access June 29, 2013

Biosorption of heavy metals by Streptomyces species — an overview

Rachid Mosbah, Mohamed Sahmoune

Page range: 1412-1422

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Abstract

Abstract Heavy metals, derived from industrial wastewater discharge, present a serious threat to human health and to natural water. Biosorption is regarded as a cost-effective biotechnology for the treatment of high volume and low concentration wastewaters containing heavy metal(s) in the order of 1 to 100 mg L−1. Among the biomaterials for heavy metal removal which have been researched during the past decades is the Streptomyces species, a by-product of an industrial antibiotic fermentation process. This paper describes the hazards posed by heavy metals effluents on the environment and use of various Streptomyces species to remove heavy metals from aqueous solution. Characterization of Streptomyces species, factors affecting biosorption, biosorption isotherms and biosorption kinetics is discussed. Graphical abstract

Open Access June 29, 2013

How to specify the structure of substituted blade-like zigzag diamondoids

Alexandru Balaban, Christoph Rücker

Page range: 1423-1430

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Abstract

Abstract The dualist of an [n]diamondoid consists of vertices situated in the centers of each of the n adamantane units, and of edges connecting vertices corresponding to units sharing a chair-shaped hexagon of carbon atoms. Since the polycyclic structure of diamondoids is rather complex, so is their nomenclature. For specifying chemical constitution or isomerism of all diamondoids the Balaban-Schleyer graph-theoretical approach based on dualists has been generally adopted. However, when one needs to indicate the location of C and H atoms or of a substituent in a diamondoid or the stereochemical relationships between substituents, only the IUPAC polycycle nomenclature (von Baeyer nomenclature) provides the unique solution. This is so since each IUPAC name is associated with a unique atom numbering scheme. Diamondoids are classified into catamantanes (which can be regular or irregular), perimantanes, and coronamantanes. Regular catamantanes have molecular formulas C4n+6H4n+12. Among regular catamantanes, the rigid blade-shaped zigzag catamantanes (so called because their dualists consist of a zigzag line with a code of alternating digits 1 and 2) exhibit a simple pattern in their von Baeyer nomenclature. Their carbon atoms form a main ring with 4n + 4 atoms, and the remaining atoms form two 1-carbon bridges. All zigzag [n]catamantanes with n > 2 have quaternary carbon atoms, and the first bridgehead in the main ring is such an atom. Their partitioned formula is Cn−2(CH)2n+4(CH2)n+4. As a function of their parity, IUPAC names based on the von Baeyer approach have been devised for all zigzag catamantanes, allowing the unique location for every C and H atom. The dualist of such a zigzag catamantane defines a plane bisecting the molecule, and the stereochemical features of hydrogens attached to secondary carbon atoms can be specified relatively to that plane. Graphical abstract

Open Access June 29, 2013

Azo-polysiloxane micelles charged with nifedipine

Anca-Irina Prisacaru, Silvia Grama, Ana Durdureanu-Angheluta, Mariana Pinteala, Nicolae Hurduc

Page range: 1431-1438

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Abstract

Abstract One recent aspect of the research study on polymers is their capability to respond to external stimuli. Of importance are photosensitive polymers due to their application in drug delivery systems, sensors, therapeutic devices or optoelectronic switches. The present paper focuses on the azo-polysiloxane micelles capacity charged with hydrophobic drugs, such as nifedipine. Azo-polysiloxanes modified with quaternary ammonium groups and which are capable to generate photo-sensitive micelles were synthesized and characterized by 1H-NMR, UV-VIS and fluorescence spectroscopy. The critical concentration of the micellar aggregation (CCA) was evaluated as was the nifedipine embedding capacity. The CCA values were influenced only by the hydrophobic/hydrophilic balance and not by the chemical structure of the quaternary ammonium groups. The disaggregation capacity of the micelles under UV irradiation was investigated as well, and the best results were obtained for the samples with higher azobenzene content. The DLS measurements evidenced micelles diameters situated in the optimum range domain (70–130 nm). The capacity to incorporate nifedipine inside the micelles was demonstrated. The micelles proved to be stable in time, 21 days after preparation with the diameter having constant values. Graphical abstract

Open Access June 29, 2013

In vitro bioactivity of Polyurethane/85S Bioglass composite scaffolds

Lachezar Radev, Darina Zheleva, Irena Michailova

Page range: 1439-1446

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Abstract

In the present work Polyurethane (PU)/Bioglass (BG) composite materials were synthesized with different content of BG (10 and 20 mol.%) as filler. The 85S Bioglass was synthesized via polystep sol-gel method. The chemical composition of BG is 85SiO2-10CaO-5P2O5 (wt.%). The synthesis of PU was carried out by a two-step polyaddition reaction. The 85S BG was added in situ during the polymerization reaction. In vitro bioactivity of the prepared composites was examined in the presence of 1.5 SBF for 7 days in static conditions. The structure of synthesized PU/BG composites before and after in vitro test was determined by XRD, FTIR and SEM. XRD of the samples before in vitro test proved that the phase of γCa2P2O7 in the PU/20BG is visible. FTIR revealed the presence of urethane bond between OH-(from BG) and NCO groups (from PU). Based on FTIR results after in vitro test in 1.5 SBF solutions, A/B-carbonate containing hydroxyapatite (CO3HA) was formed. XRD proved that HA was formed on the surface of the samples, but Ca2P2O7 does not undergo any changes in the 1.5 SBF solution. SEM depicted the nano-HA agglomerated in spherical particles after immersion in 1.5 SBF for 7 days.

Open Access June 29, 2013

The study of rutile pigments Ti1−3x CrxM2x O2

Jan Večeřa, Jan Čech, Petr Mikulášek, Petra Šulcová

Page range: 1447-1455

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Abstract

Abstract This study deals with rutile pigments of type Ti1−3x Crx M2x O2 (where M = Sb, W and x = 0, 0.05, 0.10, 0.20, 0.30, 0.50) prepared by solid state reaction. Chromium is the chromophore (coloring ion); antimony and tungsten are added for achieving electroneutrality. The effect of doping elements (M = Sb, W), calcination temperature (850, 950, 1050, 1150°C) and composition (x = 0, 0.05, 0.10, 0.20, 0.30, 0.50) on color properties, particle size and electrokinetic (zeta) potential was observed. The optimal conditions for synthesis of these rutile pigments are Sb2O3 as raw material, calcination temperature 1050°C and composition x = 0.20 (Ti0.4Cr0.2Sb0.4O2). This orange-green pigment has high stable dispersion (ζ = −43.81 mV) and good color properties (chroma C = 39.50). However, brightly orange pigment Ti0.85Cr0.05W0.10O2 (x = 0.05) synthesized at temperature 1050°C gives “the finest” color with higher chroma (C = 49.48), but less stable dispersion (ζ = −37.32 mV). In light of phase composition, the optimal calcination temperature is 1150°C. Graphical abstract

Open Access June 29, 2013

Spatial variations in the distribution of trace ionic impurities in the water-steam cycle in a thermal power plant based on a multivariate statistical approach

Dragana Živojinović, Vladana Rajaković-Ognjanović, Antonije Onjia, Ljubinka Rajaković

Page range: 1456-1470

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Abstract

Abstract In this study, a multivariate statistical approach was used to identify the key variables responsible for process water quality in a power plant. The ion species that could cause corrosion in one of the major thermal power plants (TPP) in Serbia were monitored. A suppressed ion chromatographic (IC) method for the determination of the target anions and cations at trace levels was applied. In addition, some metals important for corrosion, i.e., copper and iron, were also analysed by the graphite furnace atomic absorption spectrophotometric (GFAAS) method. The control parameters, i.e., pH, dissolved oxygen and silica, were measured on-line. The analysis of a series of representative samples from the TPP Nikola Tesla, collected in different plant operation modes, was performed. Every day laboratory and on-line analysis provides a large number of data in relation to the quality of water in the water-steam cycle (WSC) which should be evaluated and processed. The goal of this investigation was to apply multivariate statistical techniques and choose the most applicable technique for this case. Factor analysis (FA), especially principal component analysis (PCA) and cluster analysis (CA) were investigated. These methods were applied for the evaluation of the spatial/temporal variations of process water and for the estimation of 13 quality parameters which were monitored at 11 locations in the WSC in different working conditions during a twelve month period. It was concluded that PCA was the most useful method for identifying functional relations between the elements. After data reduction, four main factors controlling the variability were identified. Hierarchical cluster analysis (HCA) was applied for sample differentiation according to the sample location and working mode of the TPP. On the basis of this research, the new design of an optimal monitoring strategy for future analysis was proposed with a reduced number of measured parameters and with reduced frequency of their measurements. Graphical abstract

Open Access June 29, 2013

An experimental and theoretical study of the polar [2+3] cycloaddition reactions between 1-chloro-1-nitroethene and (Z)-C-aryl-N-phenylnitrones

Radomir Jasiński, Maria Mikulska, Andrzej Barański

Page range: 1471-1480

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Abstract

Abstract Kinetic studies and B3LYP/6-31g(d) calculations indicate the polar nature of [2+3] cycloadditions between 1-chloro-1-nitroethene to (Z)-C-aryl-N-phenylnitrones. This is clearly confirmed by the activation parameters and the substituent and solvent effects. Graphical abstract

Open Access June 29, 2013

Characterization of Slovenian coal and estimation of coal heating value based on proximate analysis using regression and artificial neural networks

Darja Kavšek, Adriána Bednárová, Miša Biro, Roman Kranvogl, Darinka Vončina, Ernest Beinrohr

Page range: 1481-1491

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Abstract

Abstract Chemical composition of Slovenian coal has been characterised in terms of proximate and ultimate analyses and the relations among the chemical descriptors and the higher heating value (HHV) examined using correlation analysis and multivariate data analysis methods. The proximate analysis descriptors were used to predict HHV using multiple linear regression (MLR) and artificial neural network (ANN) methods. An attempt has been made to select the model with the optimal number of predictor variables. According to the adjusted multiple coefficient of determination in the MLR model, and alternatively, according to sensitivity analysis in ANN developing, two descriptors were evaluated by both methods as optimal predictors: fixed carbon and volatile matter. The performances of MLR and ANN when modelling HHV were comparable; the mean relative difference between the actual and calculated HHV values in the training data was 1.11% for MLR and 0.91% for ANN. The predictive ability of the models was evaluated by an external validation data set; the mean relative difference between the actual and predicted HHV values was 1.39% in MLR and 1.47% in ANN. Thus, the developed models could be appropriately used to calculate HHV. Graphical abstract

Open Access June 29, 2013

Preparation and characterization of block copolymers containing cinnamate groups with end-capped ZnO

Florentina Jitaru, Tinca Buruiana, Gabriela Hitruc, Emil Buruiana

Page range: 1492-1504

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Abstract

Abstract ZnO-poly(2-cinnamoyloxyethyl methacrylate) and ZnO-poly(2-cinnamoyloxyethyl methacrylate)-b-poly[(poly(ethylene glycol) methyl ether methacrylate] have been prepared by atom transfer polymerization initiated through a 2-bromoisobutyryl or bromoethyl group linked onto the ZnO nanoparticle surface (ZnO-BIBB, ZnO-BEI). The structure and morphology of the hybrids were characterized using Fourier transform infrared, proton nuclear magnetic resonance, fluorescence and UV spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron (TEM) and atomic force microscopy. The existence of nanoparticles with diameters varying between 40 and 100 nm was evident in the TEM images of the pure ZnO, ZnO-PCEMA-Br-2 and the diblock copolymer. Under an excitation of 340 nm, these materials exhibit a broad emission band at around 390 nm, which was associated with the presence of ZnO in the organic matrix. Graphical abstract

Open Access June 29, 2013

Modelling and optimization of chromiumIII biosorption on soybean meal

Anna Witek-Krowiak, Daria Podstawczyk, Katarzyna Chojnacka, Anna Dawiec, Krzysztof Marycz

Page range: 1505-1517

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Abstract

Abstract In this investigation a waste biological material, soybean meal, was applied as a biosorbent for heavy metal ions (CrIII). The diffusive Webber-Morris model and the pseudo-II-order model suitably described the kinetics of CrIII ions binding on soybean meal. The Langmuir-Freundlich equation was valid for the description of the isotherm. Inductively coupled plasma optical emission spectroscopy (ICP-OES), FTIR and scanning electron microscopy with an energy dispersive X-ray analytical system (SEM-EDX) were used in order to identify the mechanism of the metal ions binding. The analysis of the composition of the enriched soybean meal confirmed the contribution of ion exchange in the biosorption process. Three-variable-three-level Box-Behnken design was used to determine the optimal conditions for biosorption of CrIII on soybean meal. The optimal conditions for predicted maximum Cr3+ uptake (61.07 mg g−1) by soybean meal were estimated by Matlab and established as temperature of 38.04°C, initial metal concentration 500 mg L−1 and biosorbent dosage 1 g L−1. Graphical abstract

Open Access June 29, 2013

The Ti-Fe-P system: phase equilibria and crystal structure of phases

Oksana Toma, Mariya Dzevenko, Anton Oliynyk, Yaroslava Lomnytska

Page range: 1518-1526

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Abstract

Abstract Phase equilibria was investigated in the Ti-Fe-P system at T = 1070 K in the region 0–67 at.% of P, employing X-ray powder diffraction. The two ternary compounds, namely Ti0.5–0.8Fe1.5−1.2P (Co2Si-type; space group Pnma; a = 0.5964(2)–0.6011(3), b = 0.3575(3)–0.3600(1), c = 0.6828(2)–0.6882(2) nm) and Ti0.85−1.25Fe1.15−0.75P (ZrNiAl-type; space group P-62m; a = 0.6071(4)–0.6117(1), c = 0.3510(9)–0.3506(1) nm) exist in the Ti-Fe-P system at this temperature. The crystal structure of the Ti0.85–1.25Fe1.15−0.75P compound was additionally determined by X-ray single crystal diffraction on the phase with stoichiometric composition. The substitutions of Ti by Fe were observed for Ti5P3.16, Ti3P and TiP phases, and Fe for Ti in the case of Fe3P, Fe2P binary compounds. Graphical abstract

Open Access June 29, 2013

Simple hydrothermal synthesis of Fe3O4-PEG nanocomposite

Yasmeen Junejo, Abdulhadi Baykal, Huseyin Sözeri

Page range: 1527-1532

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Abstract

Abstract We report a one-step hydrothermal synthesis of Fe3O4 nanoparticles coated with Polyethyleneglycol (PEG). The formation of the Fe3O4 core and the polymer coating took place simultaneously. Fe3O4/polyethylene glycol (PEG) magnetic nanocomposite with a core-shell structure with a 17±7 nm crystallite size prepared by simple hydrothermal method. VSM ( Vibrating Sample Magnetometer) analysis proved the superparamagnetic character of the nanocomposite. Graphical abstract

Open Access June 29, 2013

Quantitative determination of tolfenamic acid and its pharmaceutical formulation using FTIR and UV spectrometry

Sofia Ahmed, Muhammad Sheraz, Ceyla Yorucu, Ihtesham Rehman

Page range: 1533-1541

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Abstract

Abstract The quantitative analysis of Tolfenamic Acid (TA) both as a pure compound and in tablet dosage form has been carried out using FT-IR and UV spectroscopy. In the FT-IR method, a number of characteristic absorption peaks were examined that could be used for analytical purpose. The analysis was carried out by preparing calibration curves of peak height/area versus TA content using two points baseline correction with fixed location, and the data was also analyzed through PLS regression model. In the UV method, ethanolic solutions of the drug were analyzed at 288 nm (λmax) using 480 as the value of A (1%, 1 cm) at the analytical wavelength. The results have been compared statistically for recovery, precision, accuracy and linearity with the British Pharmacopoeial titration method that showed good validity of both test procedures. The two test methods exhibited good recovery of TA with an accuracy of 99.75–100.83% and 99.53–100.11% by FTIR spectrometry for peak height and area respectively and 100.21% for UV method. However, UV spectrometry was found to be more accurate and precise on the basis of statistical evaluation and hence can be employed in the quality control of TA in pharmaceuticals as an alternative to the titration method. Graphical abstract

Open Access June 29, 2013

Direct determination of enantiomeric enrichment of chiral, underivatized aminophosphonic acids — useful for enantioselective bioconversion results evaluation

Kinga Kozyra, Magdalena Klimek-Ochab, Małgorzata Brzezińska-Rodak, Ewa Żymańczyk-Duda

Page range: 1542-1547

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Abstract

Abstract The possibility of applying 31P NMR spectroscopy for the determination of the enantiomeric excess of the racemic mixture of non-derivatized aminophosphonic acids with small side chains has been investigated. It is proven, that the effectiveness of the application of a chiral solvating agent strongly depends on the concentration of applied shift reagent and on the pH of the particular experiment. Effectual resolution protocols are elaborated for following phosphonic acids: 1-aminoethanephosphonic acid, 1-amino-2-methylpropanephosphonic acid, 1-aminophenylmethanephosphonic acid, 1-aminophenylmethane-phosphonic acid and 1-amino-2-phenylethanephosphonic acid. Graphical abstract

Open Access June 29, 2013

Characterization of polymeric system for cisplatin delivery — analytical methods for Pt determination

Ekaterina Stoyanova, Irina Karadjova, Methody Karadjov, Neli Koseva

Page range: 1548-1553

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Abstract

Abstract Cis-diamminedichloroplatinum(II) (cisplatin) was immobilized in a star-shaped polymer carrier. In order to define whether this polymer could be used as a drug delivery system for cisplatin, its characteristics, e.g. loading efficiency and release profile of cisplatin from the polymer in phosphate buffered saline (PBS), have to be assessed, and hence an appropriate analytical procedure for precise and reliable determination of Pt(II) must be established. Optimal instrumental parameters for Pt measurement by commonly used atomic spectrometric methods ETAAS and ICP-OES in various examined media were defined. Matrix interferences observed that were related to both techniques were evaluated, and analytical figures of merit were compared and critically discussed. Graphical abstract

Open Access June 29, 2013

Potentiometric cholesterol biosensing application of graphene electrode with stabilized polymeric lipid membrane

Georgia-Paraskevi Nikoleli, Zafar Ibupoto, Dimitrios Nikolelis, Vlassis Likodimos, Nikolas Psaroudakis, Nikolaos Tzamtzis, Magnus Willander, Tibor Hianik

Page range: 1554-1561

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Abstract

Abstract A novel potentiometric cholesterol biosensor has been fabricated through the immobilization of the stabilized polymeric lipid membrane onto graphene electrode. The stabilized polymeric lipid membrane is composed of cholesterol oxidase enzyme and polymerization mixture; which holds paramount influence on the properties of the cholesterol biosensor. The presented biosensor reveals an appreciable reproducibility, good selectivity and high sensing capability with a linear slope curve of ∼64 mV per decade. The strong biocompatibility among stabilized polymeric lipid membranes and human biofluids provides the possibility to use for real blood samples and other biological applications. Graphical abstract

About this journal

Open Chemistry is a peer-reviewed, open access journal that publishes original research, reviews, and communications in the fields of chemistry in an ongoing way. Our central goal is to provide a hub for researchers working across all subjects to present their discoveries, and to be a forum for the discussion of the important issues in the field.

There are no submission charges. In order to sustain the production of our fully-refereed open access journal, each article accepted for publication in Open Chemistry is subject to Article Processing Charges (APC).

Special/Topical Issues:

Advanced Nanomaterials for Energy, Environmental and Biological Applications
Submission deadline: 30.09.2023
Marine Environmental Sciences and significance of the multidiscplinary approaches for assessing pollutions, remedies, and predictions
Submission deadline: 30.09.2023
Energy conversion and energy storage reactions
Submission deadline: 30.09.2023
Recent Trends in Green Chemistry
Submission deadline: 30.09.2023
Therapeutic Potentials of Natural Compounds Targeting Malaria
Submission deadline: 30.09.2023
Advancements at the Nexus of Mathematics, Artificial Intelligence, and IoT in Medicinal Chemistry and Healthcare
Submission deadline: 30 June 2024

You are also welcome to submit your Special Issue proposal by contacting Managing Editor at openchemistry@degruyter.com

Cooperation with conferences:

Catalysis Conferences
Submission deadline: 30.09.2023
MATERIALS and MAT Conferences 2023
Submission deadline: 30.09.2023
Euro-Mediterranean Conference for Environmental Integration 2023
Submission deadline: 30.10.2023
CFP Applied Biochemistry and Biotechnology 2023
Submission deadline: 30.11.2023
World Chemistry Forum 2024
Date: 1.02 - 3.02.2024
2nd International Summit on Biopolymers and Polymer Science
Date: 10-12.06.2024
4th Edition of the International Conference on Green Chemistry and Renewable Energy
Date: 17-19.06.2024
11th International Conference on Materials Research and Nanotechnology
Date: 1.07 – 2.07.2024
2nd Global Summit on Advanced Materials and Sustainable Energy (GAMSE24)
Submission Deadline: 31.07.2024
European Congress of Applied Chemistry (ECAC24)
Submission Deadline: 31.07.2024