• Issue front cover thumbnail

      Volume 128, Issue 1

      January 2016,   pages  a-164

    • Contents

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    • General Editorial on Publication Ethics

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    • Design and synthesis of nanoporous perylene bis-imide linked metalloporphyrin frameworks and their catalytic activity

      Manoj Kumar Singh Debkumar Bandyopadhyay

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      Two nanoporous perylene bis-imide linked metalloporphyrin framework catalysts have been synthesized via condensation of 5,10,15,20-tetrakis-(4′-aminophenyl) iron(III) porphyrin chloride or 5,10, 15,20-tetrakis-(4′-aminophenyl) manganese(III) porphyrin chloride with perylene-3,4,9,10-tetracarboxylic dianhydride. Both the materials were crystalline in nature and were characterized by electron microscopy techniques, solid-state 1H-13C CP/MS NMR, powder X-ray diffraction (PXRD), and magnetic susceptibility measurements. The nitrogen gas physisorption study has indicated that both materials are porous in nature and have BET surface area with 653 m2/g and 974 m2/g with uniform pore size of 2.8 nm. These materials were found to act as very good heterogeneous catalysts for selective oxidation of alkanes and alkenes with tert-butyl hydroperoxide and were not degraded even after multiple uses up to 10 cycles.

    • Design and synthesis of ruthenium(II) OCO pincer type NHC complexes and their catalytic role towards the synthesis of amides

      Muthukumaran Nirmala Periasamy Viswanathamurthi

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      The present contribution describes the synthesis and characterization of a family of robust ruthenium complexes, supported by a tridentate pincer ligand of the type bis-phenolate-𝑁-heterocyclic carbene [𝑡Bu(OCO)2−] (NHC). Ruthenium(II) complexes (1-3) bearing bis-phenolate-𝑁-heterocyclic carbene ligand were synthesized in good yields by the reaction of imidazolinium proligand (HL) with metal precursors [RuHCl(CO)(EPh3)2(B)] (E = P or As; B = PPh3, AsPh3 or Py) by transmetalation from the corresponding silver carbene complex. All the Ru(II)-NHC complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The tridentate nature of the 𝑡Bu(OCO)2− ligand as well as some level of steric protection provided by the 𝑡Bu groups may rationalize the excellent stability of the Ru-Ccarbene bond in the present systems. Moreover, for the explorations of catalytic potential of the synthesized compounds, all the three [Ru-NHC] complexes (1-3) were tested as catalysts for amidation of alcohols with amines. Notably, the complex 1 was found to be very efficient and versatile catalyst towards amidation of a wide range of alcohols with amines.

    • Synthesis, spectral properties and DNA binding and nuclease activity of lanthanide (III) complexes of 2-benzoylpyridine benzhydrazone: X-ray crystal structure, Hirshfeld studies and nitrate-𝜋 interactions of cerium(III) complex

      Karreddula Raja Akkili Suseelamma Katreddi Hussain Reddy

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      The lanthanide(III) complexes of general formula of [Ln(BPBH)2(NO3)3] (where, Ln = La, Ce, Pr, Nd and BPBH = 2-benzoylpyridine benzhydrazone) have been synthesized and characterized by elemental analysis, molar conductance, spectroscopic (UV, IR), electrochemical and single crystal X-ray diffraction studies. The coordination mode of the ligand and the geometry of [Ce(BPBH)2(NO3)3] are confirmed by single crystal X-ray studies. The crystals are monoclinic with C2/c crystallographic symmetry. The central metal is 12 coordinated and the coordination polyhedron around the cerium atom can be described as a distorted icosahedron. The existence of nitrate. . . 𝜋 and CH. . . 𝜋 stacking interactions in the [Ce(BPBH)2(NO3)3] leads to a supramolecular arrangement in its network. The binding properties of these complexes with calf-thymus DNA have been investigated by viscosity measurements. The complexes show more nuclease activity in the presences of H2O2.

    • Iron(III) Chloride mediated reduction of Bis(1-isoquinolylcarbonyl)amide to an Amide

      Rojalin Sahu Papuli Chaliha Vadivelu Manivannan

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      In methanol, FeCl3 reacted readily with L1H (L1H = bis(1-isoquinolylcarbonyl)amide) and afforded a complex having the formula [Fe(L2)Cl2] (1) {L2 = 𝑁-((1-isoquinolyl)(methoxy)methyl)isoquinoline-1-carboxamide ion}. This reaction involves reduction of one of the two carbonyl groups present in L1H to (methoxy)methyl group. A plausible mechanism for the conversion of L1H to L2 has been proposed. Determination of molecular structure of 1 confirmed this conversion. Fe(III) ion is surrounded by three nitrogen atoms of the ligand and two chloride ions, imparting a rare distorted trigonal bipyramidal N3Cl2 coordination environment.

    • Synthesis, characterization and studies on antioxidant and molecular docking of metal complexes of 1-(benzo[d]thiazol-2-yl)thiourea

      Harinath Yapati Subba Rao Devineni Suresh Chirumamilla Seshaiah Kalluru

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      In the present study, a new thiourea derivative bearing benzothiazole ligand, 1-(benzo[d]thiazol-2-yl)thiourea (btt) and its ternary metal (Cu(II), Co(II) and Ni(II)) complexes were synthesized. The structural characterization was carried out by micro analysis, IR, 1H-NMR, EPR, UV-Visible spectral analyses, molar conductance and thermal analysis studies. Spectral studies of complexes revealed that the metal complexes have distorted octahedral geometry. Molecular modelling study was performed to evaluate the recognition of target compounds at the 3MNG binding pocket. The docking results revealed that copper complex selectively binds to the crucial amino acid residues in the active site of 3MNG. The in vitro antioxidant activity of the ligand and its metal complexes was assayed by radical scavenging activity (DPPH, H2O2 and NO) and ferric reducing antioxidant power (FRAP) methods. The ligand showed moderate antioxidant activity whereas the metal complexes exhibited better antioxidant activity than that of the ligand. The results of the four methods proved that the copper complex is the most potent antioxidant among all the tested compounds.

    • Formation of BH3 Adducts with Pyridine-2-Methylaminophosphine ligands: An experimental and computational study

      Harinath Adimulam Dwijendra P Kukri Bhabani S Mallik Tarun K Panda

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      The reaction of pyridine-2-methylaminophosphine [C5H4N-CH2NHPPh2] (1) and pyridine-2-methylphosphinoselenoic amide [C5H4N-CH2NHP(Se)Ph2] (2) with BH3·SMe2 yields the corresponding adducts [C5H4N(BH3)-CH2NHP(BH3)Ph2] (1a), and [C5H4N(BH3)-CH2NHP(Se)Ph2] (2a), respectively. The solid state structures of both the compounds were established by single crystal X-ray diffraction analysis. The phosphorus and the pyridine nitrogen atoms are coordinated to the boron atom in the case of 1a whereas only pyridine nitrogen atom is attached to the BH3 group in the case of 2a. To understand the nature of P-B/ N-B bonds and to compare the basicities of pyridine nitrogen, amino nitrogen and phosphorus atoms, density functional theoretical (DFT) calculations were performed on the BH3 adducts 1a and 2a. The results are consistent with the experimental results.

    • 1,3,5-Trimethylpyrazolium chloride based ionogel as an efficient and reusable heterogeneous catalyst for the synthesis of benzimidazoles

      Pankaj Sharma Monika Gupta

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      A new approach for the synthesis of benzimidazoles using ionogel under solvent-free conditions is reported. Catalytic activity of ionogel was compared with silica coated with ionic liquid (silica-IL) and it was found that ionogel is highly active compared to silica-IL for the synthesis of benzimidazoles. Moreover, ionogel was recyclable for the synthesis of benzimidazoles.

    • Oxidative dehydrogenation of propane with K-MoO3/MgAl2O4 catalysts

      Serkan Naci Koc Kubra Dayioglu Hasan Ozdemir

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      In this study, for the first time, MoO3/MgAl2O4 catalysts and their potassium-promoted forms were prepared and tested for oxidative dehydrogenation of propane. Catalysts were characterized with XRD, BET, NH3-TPD, TPR and XPS methods. Catalytic activity measurement was done with quartz microreactor between 450 and 550°C. It has been observed that the conversion of propane increased with temperature and total hydrocarbon selectivity increased with molybdenum oxide content. The acidity of catalysts decreased with potassium addition due to interaction with MoO3 sites. For this reason total hydrocarbon selectivity highly increased.

    • Cycloisomerization of acetylenic oximes and hydrazones under gold catalysis: Synthesis and cytotoxic evaluation of isoxazoles and pyrazoles

      J C Jeyaveeran Chandrasekar Praveen Y Arun A A M Prince P T Perumal

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      The synthesis of substituted isoxazoles and pyrazoles through a general cycloisomerization methodology has been reported. The capability of gold(III) chloride to promote cycloisomerization of both 𝛼, 𝛽-acetylenic oximes and 𝛼, 𝛽-acetylenic hydrazones is the centrepiece of the strategy. A range of acetylenic precursors were investigated to afford 28 examples of the products with good to excellent chemical yields. Selected compounds were screened for their cytotoxic potential towards COLO320 cancer cell lines. The IC50 values of the tested compounds were in the micromolar range, with the best compound, 5-(6-Methoxy-naphthalen-2-yl)-3-phenyl-isoxazole (3h) displaying an IC50 of 38.9 𝜇M. For this compound, the crystal structure in complex with Aurora-A kinase was obtained which revealed details of its binding mode within the active site with a free energy of binding -9.54 kcal/mol.

    • Synthesis and antibacterial activity of new chiral 𝑁-sulfamoyloxazolidin-2-ones

      Fouzia Bouchareb Malika Berredjem Samira Ait Kaki Amel Bouaricha Abdeslem Bouzina Billel Belhani Nour-Eddine Aouf

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      A new series of 𝑁, 𝑁′-bis-oxazolidinones-sulfone and 5-chloromethylsulfamoyl-oxazolidin-2-ones have been synthesized in three steps (carbamoylation, sulfamoylation and cyclization) starting from 1,3-dichloroporopan-2-ol, chlorosulfonyl isocyanate and primary or secondary amines. Synthesis has been carried out following simple methodology in excellent isolated yields. The structure and purity of the original compounds were confirmed by IR, NMR, and MS. The compounds were evaluated for their in vitro antibacterial activity against some Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia Coli, Klebsiella pneumonieae, Acinetobacter, Pseudomonas aeruginosa, Enterococcus, Salmonella sp. The compounds showed moderate to good antibacterial activity.

    • Cu-MCM-41 nanoparticles: An efficient catalyst for the synthesis of 5-substituted 1𝐻-tetrazoles via [3+2] cycloaddition reaction of nitriles and sodium azide

      Mohammad Abdollahi-Alibeik Ali Moaddeli

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      [3+2] cycloaddition reaction of various types of nitriles and sodium azide (NaN3) were studied in the presence of nano-sized Cu-MCM-41 as an efficient recoverable heterogeneous catalyst. Nano-sized Cu-MCM-41 mesoporous molecular sieves with various Si/Cu molar ratios were synthesized by direct insertion of metal ions at room temperature. The textural properties of the materials have been studied by means of XRD, FTIR, SEM and TEM techniques. Catalytic behavior of Cu-MCM-41 was also investigated by pyridine absorption and potentiometric titration. The reactions data verified characterization results and show that Cu-MCM-41 with Si/Cu molar ratio of 20 has considerably better catalytic activity compared to the other molar ratios. To investigate reusability, the catalyst was recovered by simple filtration and reused for several cycles with consistent activity.

    • Thiophene-bithiazole based metal-free dye as DSSC sensitizer: Effect of co-adsorbents on photovoltaic efficiency

      Jayanthy S Panicker Bijitha Balan Suraj Soman Tanwistha Ghosh Vijayakumar C Nair

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      A new molecule consisting of a bithiazole chromophore sandwiched between two thiophenes, functionalized with benzothiophene unit at one end and cyanoacrylic acid at the other end (BT1) was synthesized, photophysical properties were studied and employed as a photosensitizer in dye-sensitized solar cells (DSSCs). The molecule exhibited an intense absorption in the UV-visible region with absorption extending up to 500 nm. The ground and excited state potentials of BT1 were calculated to be 1.29 and -0.65 V, respectively vs. NHE using cyclic voltammetry. The ground state energy level is more positive than the triiodide electrolyte and excited state energy level is considerably more negative than the TiO2 satisfying the energetic requirements for a photosensitizer in DSSC. The solar cells fabricated from BT1 exhibited an efficiency of 1.13%. The effect of various co-adsorbents (CDCA, TP1 and TP2) on the DSSC performance was investigated in detail. In the presence of CDCA, the photovoltaic efficiency was enhanced to 1.25%, whereas, in the presence of TP1 and TP2, the efficiency lowered to 0.20% and 0.59%, respectively. The increased efficiency in the presence of CDCA could be attributed to the prevention of the aggregation of dye molecules induced by CDCA. On the other hand, TP1 and TP2 were found to be not as effective as CDCA to prevent aggregation leading to the lowering of photoconversion efficiency.

    • Experimental and theoretical investigation of benzyl-𝑁-pyrrolylketene, one- step procedure for preparing of new 𝛽-lactams by [2+2] cycloaddition reaction

      Masoumeh Behzadi Kazem Saidi Mohammad Reza Islami Hojatollah Khabazzadeh

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      3-Phenyl-2-(1-𝐻-pyrrol-1-yl) propanoic acid has been used as a ketene source in synthesizing of monocyclic-2-azetidinones. Hindrance in ketene and imines successfully controlled the diastereoselectivity of the reaction. For example, in some cases only one isomer was achieved. By using Mukaiyama reagent, the leaving group in acid was activated and the by-products were separated by simple aqueous work-up. DFT calculation indicated that the benzyl-𝑁-pyrrolylketene has nonconjugated structure and the pyrrolyl ring is perpendicular to the ketene plane in both the twisted and planar structures.

    • Effects of temperature and CO2 pressure on the emission of N,N′-dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important?

      Kizhmuri P Divya Michael J Bertocchi Richard G Weiss

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      Static and dynamic fluorescence measurements have been made on four 𝑁,𝑁′−dialkylated perylene diimides in films of poly(alkyl methacrylate)s (PAMAs) with 5 different alkyl groups and in a ‘model solvent’, 𝑛-butyl acetate, over wide temperature ranges. The results indicate that the excited singlet states of the perylene guest molecules are controlled primarily by chain relaxations rather than hole free volumes in the polymer matrixes. The short singlet lifetimes of the perylene molecules require that the guest molecules respond primarily to the environments experienced by their ground states within the PAMA matrixes; each of the PAMAs offers slightly different locations in which the guest molecules can reside as a result of interactions between the 𝑁−alkyl substituents on the imide groups of the perylenes and the alkyl groups on the PAMA side chains. PAMAs with branched side chains were found to have a larger influence than PAMAs with linear side chains on the fluorescence properties of the guest molecules. The results are compared to those employing pyrenyl derivatives (with much longer excited singlet lifetimes) in the same PAMA films. The overall results indicate that the perylenes can be used as a complementary probe of local polymer chain dynamics, but they are less sensitive to their environments than are pyrenyl groups. However, they offer some distinct advantages:

      1. a much wider range of 𝑁,𝑁′−disubstituted perylene diimides can be synthesized easily;

      2. those substituents can be designed to allow a greater or lesser interaction with an anisotropic host matrix. Also, rapid conformational changes of a bis-perylene derivative appear to be restricted in the polymer matrixes. Those restrictions appear reduced when the polymer films are placed under high pressures of the plasticizing gas, CO2, but not when they are under equal pressures of a much less intervening gas, N2.

    • Highly selective detection of Zn2+ and Cd2+ with a simple amino-terpyridine compound in solution and solid state

      Duobin Chao

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      A simple amino-terpyridine sensor exhibits highly selective detection of Zn2+ and Cd2+ in solution and solid state based on the intramolecular charge transfer (ICT) effect. The detection limits were determined to be 0.184 𝜇M for Zn2+ and 0.176 𝜇M for Cd2+. Job’s plot experiments suggest a 1:1 binding mode between the sensor and metal ions like Zn2+ and Cd2+. The resulting complexes were found to be emissive in solution and solid state.

    • Impact of electric field on Hofmeister effects in aggregation of negatively charged colloidal minerals

      Ying Tang Hang Li Hualing Zhu Rui Tian Xiaodan Gao

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      In this study, the aggregation kinetics of negatively charged colloidal minerals in Na+, K+, NH+4 , Mg2+, Ca2+ and Cu2+ solutions were measured and Hofmeister effects therein were estimated through total average aggregation (TAA) rates and critical coagulation concentration (CCC). Hofmeister effects of TAA rates increased exponentially with the increase in electric field strength, which cannot be explained by the classical theories (i.e., ionic size, hydration and dispersion forces), indicating strong electric field at colloidal surface was an indispensable factor in studying Hofmeister effects. Meanwhile, Hofmeister series of CCC values Na+ > K+ > NH+4 > Mg2+ > Ca2+ > Cu2+ show fine correlation with the polarization of various cations, implying that onic polarization in strong electric field would be responsible for Hofmeister effects in aggregation of colloidal minerals, and the deduction was confirmed by the calculated results of electrostatic interactions between colloidal minerals.

    • Anodization of Aluminium using a fast two-step process

      Murugaiya Sridar Ilango Amruta Mutalikdesai Sheela K Ramasesha

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      Ultra-fast two-step anodization method is developed for obtaining ordered nano-pores on aluminium (Al) foil. First anodization was carried out for 10 min, followed by 3 min of second anodization at high voltage (150 V) compared to previous reports of anodization times of 12 h (40-60 V). The pore dimensions on anodized alumina are 180 nm for pore diameter and 130 nm for inter-pore distance. It was evident that by increasing the anodization voltage to 150 V, the diameter of the pores formed was above 150 nm. The electrolyte and its temperature affect the shape and size of the pore formation. At lower anodization temperature, controlled pore formation was observed. The anodized samples were characterized using the field emission scanning electron microscope (FE-SEM) to determine the pore diameter and inter-pore distance. Using UVVisible spectroscopy, the reflectance spectra of anodized samples were measured. The alumina (Al2O3) peaks were identified by x-ray diffraction (XRD) technique. The x-ray photo electron spectroscopy (XPS) analysis confirmed the Al 2p peak at 73.1 eV along with the oxygen O 1s at 530.9 eV and carbon traces C 1s at 283.6 eV.

    • Electron irradiation of carbon dioxide-carbon disulphide ice analog and its implication on the identification of carbon disulphide on Moon

      B Sivaraman

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      Carbon dioxide (CO2) and carbon disulphide (CS2) molecular ice mixture was prepared under low temperature (85 K) astrochemical conditions. The icy mixture irradiated with keV electrons simulates the irradiation environment experienced by icy satellites and Interstellar Icy Mantles (IIM). Upon electron irradiation the chemical composition was found to have altered and the new products from irradiation were found to be carbonyl sulphide (OCS), sulphur dioxide (SO2), ozone (O3), carbon trioxide (CO3), sulphur trioxide (SO3), carbon subsulphide (C3S2) and carbon monoxide (CO). Results obtained confirm the presence of CS2 molecules in lunar south-pole probed by the Moon Impact Probe (MIP).

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