• Issue front cover thumbnail

      Volume 129, Issue 10

      October 2017,   pages  1512a-1657

    • Table of Contents

      More Details Abstract Fulltext PDF
    • Synthesis and phosphatase activity of a Cobalt(II) phenanthroline complex

      MAMONI GARAI DHANANJAY DEY HARE RAM YADAV MILAN MAJI ANGSHUMAN ROY CHOUDHURY BHASKAR BISWAS

      More Details Abstract Fulltext PDF

      A mononuclear cobalt(II) complex, [Co(phen) ₂Cl ₂], (phen = 1,10-phenanthroline) has been synthesized and structurally characterized by different spectroscopic methods including single crystal X-ray structural study.X-ray crystal structural analysis revealed that the cobalt(II) complex crystallizes in amonoclinicsystem with C2/c space group and exists in cis-configuration in its crystalline state. Room temperature magnetic measurement accounts for 3e paramagnetism and indicates high spin cobalt(II) in the solid state. The cobalt(II) complex has been evaluated as a functional model for phosphatase enzyme by using 4-nitrophenylphosphate (PNPP) as a standard substrate in aqueous DMF medium. This mononuclear cobalt(II) complex exhibits good hydrolytic phosphoester cleavage efficiency with kcat value of 3.78 × 10 ²h ⁻¹.

    • Two new supramolecular compounds induced by novel vinylpyridine cationic templates: synthesis, structures and enhanced photocatalytic properties

      MIN XIAO SU-MIN LI YUN-YIN NIU

      More Details Abstract Fulltext PDF

      Two novel complexes {(Pepy)[Cu ₂ (SCN) ₄]}n (1) and {(Pepy)[Cu ₂Br ₄]}n (2) [Pepy=1-2- (Pyridinium-1-yl)-1-ethenyl) pyridinium] based on vinylpyridinium organic cation and cuprous salts have been synthesized and characterized by X-ray diffractometry. Compound 1 has a 2D polypseudorotaxane structure and compound 2 presents a 1D chain structure. Furthermore, the thermal gravimetric analysis (TGA),UV–Vis diffusereflectance spectra, the morphology and the photocatalytic performances were studied carefully. Remarkably, both 1 and 2 exhibited good photocatalytic degradation abilities towards some dyes.

    • Macrocyclic cyclodiphosphazane [{P(μ-t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂: synthesis of chalcogen derivatives and gold(I) complex

      VITTHALRAO S KASHID JOEL T MAGUE MARAVANJI S BALAKRISHNA

      More Details Abstract Fulltext PDF

      The synthesis of a Schiff base-appended macrocycle [{P(μ--t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂(1) containing cyclodiphosphazane moieties is described. Reactions of 1 with H₂ O₂ and elemental selenium yielded derivatives tetrakis(oxide) [{P(O)(μ--t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂ (2) and tetrakis(selenide)[{P(Se)(μ--t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂ (3), in ∼80% yield. Tetragold complex [Au ₄Cl ₄ {{P(μ--t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂ }₂] (4) was prepared by reacting 1 with [AuCl(SMe₂)] in 1:4 molar ratio. All the compounds have been characterized by various spectroscopic techniques. The molecular structure of 3 was confirmed by single crystal X-ray analysis.

    • Synthesis, characterization, Hirshfeld surface and theoretical properties of (C ₇H ₁₀N) ₄ [H ₂P ₂Mo ₅O ₂ ₃] · H ₂O

      ALI HARCHANI MONIKA KUCˇ ERÁKOVÁ MICHAL DUŠEK AMOR HADDAD

      More Details Abstract Fulltext PDF

      The reaction of molybdic acid, phosphoric acid and copper(II) sulfate pentahydrate with m-toluidine in aqueous solution at room temperature furnished a new diphosphopentamolybdate (C ₇H ₁₀N) ₄ [H ₂P ₂Mo ₅O ₂ ₃] · H ₂O (1). A single-crystal X-ray diffraction study showed that the compound crystallizes in the triclinic crystal system with space group P − 1 and unit cell constants, a = 12.833 (3) Å, b = 13.9855 (4) Å, c = 14.9446 (4) Å, α = 64.607 (3)◦, β = 70.578 (2)◦, γ = 65.713 (3)◦. The sample was also analyzed by energydispersive spectroscopy (EDS), infrared spectroscopy (IR) andUV-visible spectroscopy. Using the refined atomic structure, Hirshfeld surface analysis and Semi-empirical calculations were performed to study the intermolecularinteractions and calculate theoretical properties of 1.

    • Expeditious synthesis of coumarin-pyridone conjugates molecules and their anti-microbial evaluation

      RAJNI KHAJURIA SHEENA MAHAJAN AMBICA KAMAL K KAPOOR

      More Details Abstract Fulltext PDF

      An expedient synthesis of coumarin-pyridone conjugate molecules 2a-o is reported via one-pot reaction between (E)-3-(3-arylacryloyl)-2H-chromen-2-ones 1a-o, ethyl 2-nitroacetate and ammonium acetate. The structures of synthesized compounds have been unambiguously confirmed by spectroscopic analyses (NMR, IR and MS). All the compounds were screened for their anti-microbial activities against three Gram-positive bacterial strains, two Gram-negative bacterial strains and four fungal organisms. Compounds 2d, 2i, 2k, 2oexhibited mild anti-bacterial activity and 2d, 2m were found to be moderately active against all the tested fungal organisms. Compound 2k showed good inhibitory potential against the tested yeasts organisms.

    • A new Co(III) complex of Schiff base derivative for electrochemical recognition of nitrite anion

      HAKAN YILMAZ ABDULKADIR KOCAK MAOWULIDAN DILIMULATI YUNUS ZORLU MUBERRA ANDAC

      More Details Abstract Fulltext PDF

      The synthesis and characterization of a new Co(III) complex of a salphen-type Schiff base ligand, (E)-2-{[(2-aminopyridin-3-yl)imino]methyl}-4,6-di-tert-butylphenol (HL), are reported. The characterization has been carried out using X-ray single crystallographic, thermogravimetric, and spectroscopic techniques. The complex has been combined with polyvinyl chloride (PVC) membrane of various compositions and tested as an electrochemical electrode towards recognition of several anions. The electrode exhibits exceptional electrochemical recognition for the nitrite (NO⁻ ₂ ) anion in aqueous media. The electrode exhibited a linear response to NO⁻ ₂ with a detection limit of 5.76μM and displayed a linear Nernstian slope over the nitriteconcentration range of 1.0 × 10⁻⁵–1.0 × 10⁻¹ M in the pH range of 3–7 and a fast response time of less than 10 seconds. Theoretical calculations showed that the sensing could be via anion exchange in the Co(III) complex.

    • Classical dynamics simulations of interstellar glycine formation via CH₂ = NH + CO + H₂O reaction

      YOGESHWARAN KRISHNAN ALLEN VINCENT MANIKANDAN PARANJOTHY

      More Details Abstract Fulltext PDF

      Formation of simple organic species such as glycine in the interstellar medium and transportation to earth via meteorites is considered to be a possible route for ‘Origin of Life’ on earth. Glycine formation has been proposed to occur via two different pathways involving formaldehyde (HCHO) and methanimine (CH₂ = NH) as key intermediates. In the second pathway, which is the topic of this paper, CH₂ = NH reacts with CO and H₂O forming neutral glycine. In a recent article (Nhlabatsi et al. in Phys. Chem. Chem. Phys. 18:375–381, 2016), detailed electronic structure calculations were reported for the reaction between CH₂ = NH, CO and (H₂O)n, n = 1, 2, 3, and 4, forming glycine in the interstellar media. The presence of additional water molecule(s) for this reaction reduces reaction barrier - thus exhibiting a catalytic effect. This effect was described in terms of efficient proton transfer mediated by the additional water molecule through a relay transport mechanism. In thepresent article, we report ab initio classical trajectory simulations for the interstellar formation of glycine for the above mentioned reaction with n = 1 and 2. The trajectories were generated on-the-fly over a density functionalB3LYP/6-31++G(3df,2pd) potential energy surface. Our simulations indicate that the above proposed catalytic effect by the additional water molecule(s) may not be a classical effect.

    • Synthesis of 7-arylethyl-5-arylpyrazolo[1,5-a]pyrimidines through an aza-Michael addition/nucleophilic addition/1,3-hydrogen transfer cascade

      ZHENG LI DEMENG XIE JIAOJIAO HE YAN DU JINGYA YANG

      More Details Abstract Fulltext PDF

      An efficient method for the synthesis of pyrazolo[1,5-a]pyrimidines by the tandem reactions of dienones with pyrazole-3-amine through an aza-Michael addition/nucleophilic addition/1,3-hydrogen transfer process in the presence of potassium hydroxide is described. This protocol offers access to 7-arylethyl-5-arylpyrazolo[1,5-a]pyrimidines in good to excellent yield. Meanwhile for 4-substituted dienones, different products, 7-arylethylene-5-arylpyrazolo[1,5-a]pyrimidines, are given through an aza-Michael addition/nucleophilic addition/oxidation process. A gram-scale reaction has been performed to demonstrate the potency of optimized procedure for the scale-up process.

    • Iron(II) and copper(II) phthalocyanine-catalyzed synthesis of 2-nitro-4-methylsulfonylbenzoic acid under mild conditions

      CHENG HUANG RUI LIU CAITING ZHANG QIPENG CHENG HONGJUN ZHU

      More Details Abstract Fulltext PDF

      A novel methodwas developed to produce 2-nitro-4-methylsulfonylbenzoic acid (NMSBA) from the oxidation of 2-nitro-4-methylsulfonyltoluene (NMST) by oxygen catalyzed by iron(II) phthalocyanine (FePc) and copper(II) phthalocyanine (CuPc). The order of activity for oxidation of NMST was found to be: FePc >CuPc. Meanwhile, major reaction parameters such as concentrations of catalyst and NaOH, reaction temperature and oxygen pressure have been investigated. Through optimization of the reaction parameters, the highest yield of NMSBA and conversion of NMST (up to 53%, 89.3%, respectively) were achieved with oxygen (2.0 MPa), FePc (1.0×10⁻⁴ mol L ⁻¹), NaOH (0.6 mol L⁻¹ ), in methanol at 55◦C for 8 h. A plausible mechanism for thiscatalytic process is proposed which involved deprotonation and radical pathways.

    • Reaction of three cyclic thioester ligands with triiron dodecacarbonyl and possible reaction mechanisms

      ZHIYIN XIAO YONGLI WANG XUEYUAN CHEN JIAO LONG ZHENHONG WEI

      More Details Abstract Fulltext PDF

      Three cyclic thioesters of the formula “−SCH ₂CH ₂SCO(CH ₂)n −” (L ₁, n = 0;L ₂,= 1,L ₃, n = 2) and their reactions with Fe ₃ (CO) ₁₂ are reported. All the reactions produced a known diiron complex, [Fe ₂ (μ-S ₂C ₂H ₄)(CO) ₆] (1), which suggested that in the reactions, cleavage of C-S bond to generate “SCH ₂CH ₂S” fragment is a common pathway for all the three ligands. In the case of ligand L ₂, a new complex 2, [Fe ₂{μ-SC ₂H ₄ (SCH ₂)- κ}(CO) ₆] was isolated and structurally characterized. In the reaction of ligand L ₃, an unknown iron carbonyl product was isolated in addition to complex 1. Although its precise structure was not established due to its instability and low yield, its infrared spectrum and decomposing into complex 1 impliedthat the product may be a cluster with higher nuclearity. The experimental observations suggested that with the increase of the ring size of the cyclic thioester ligands, further bond cleavages were involved in the reaction inaddition to that leading to complex 1.

    • Enantioselective aminocatalysis: Michael addition of unactivated ketones to nitroolefins catalyzed by D-fructose derived monofunctional primary amine

      KHIANGTE VANLALDINPUIA PORAG BORA GRACE BASUMATARY RAHUL MOHANTA GHANASHYAM BEZ

      More Details Abstract Fulltext PDF

      Organocatalytic asymmetric Michael addition is considered among the most extensively studied, yet challenging stereoselective reactions due to the fact that the electrophilic prochiral carbon in Michael acceptor lies away from stereodirecting groups of the catalyst. Although there is a report on stereoselective organocatalysis in Michael addition employing monofunctional secondary amine, the use of monofunctional primary amine forthe said reaction is not reported till date. In fact, no monofunctional aminocatalyst is reported yet for the synthesis γ-nitro carbonyl compounds. Here we report our preliminary results on the enantioselective Michael addition of different ketones to nitro olefins catalysed by monofunctional primary amine (1) derived from d-fructose.

    • Resolution of the Identity and Cholesky Representation of EOM-MP2 Approximation: Implementation, Accuracy and Efficiency

      DINESH KUMAR ACHINTYA KUMAR DUTTA PRASHANT UDAY MANOHAR

      More Details Abstract Fulltext PDF

      We present a Resolution of Identity and Cholesky Decomposition Based Implementation of EOMMP2 approximation. The RI and CD based EOM-MP2 shows significant speed-up and less storage requirement than the conventional canonical version and can be applied to very large systems. The newalgorithm used for this implementation eliminates the most storage requiring four-index quantities resulting in the decrease of storage requirement, reduction in I/O penalties and improved parallel performance, at the expense of more floating point operations. Therefore, the speed-up compared to conventional EOM-MP2 method is more prominent in case of EA, EE and SF case where the storage bottleneck is significant than the EOM-IP-MP2 method, where thestorage requirement is significantly less. However, the RI/CD based EOM-IP-MP2 can be coupled with frozen natural orbitals to gain further speed-up.

    • Catalytic aspects of a copper(II) complex: biological oxidase to oxygenase activity

      BISWAJIT CHOWDHURY MILAN MAJI BHASKAR BISWAS

      More Details Abstract Fulltext PDF

      A coper(II) complex, [Cu(dpa)2(OAc)](ClO4) (1) [dpa =2, 2'-dipyridylamine; OAc = acetate], has been synthesized and crystallographically characterized. X-ray structure analysis revealed that this mononuclear Cu(II) complex crystallizes as a rare class of hexa coordination geometry named bicapped square pyramidalgeometry with P2₁/c space group. This copper complex displays excellent catalytic efficiency, kcat /KM (h⁻¹) = 6.17 × 10⁵ towards the oxidative coupling of 2-aminophenol (2-AP) to aminophenoxazin-3-one. Further, upon stoichiometric addition of copper(II) complex to 3,5-DTBC in presence of molecular oxygen in ethanol medium, the copper complex affords predominantly extradiol cleavage products along with a small amount of benzoquinone and a trace amount of intradiol cleavage products at a rate, kobs = 1.09 × 10⁻³ min ⁻¹, which provide substantial evidence for the oxygen activation mechanism. This paper presents a novel addition of a copper(II) complex having the potential to mimic the active site of phenoxazinone synthase and catechol dioxygenase enzymes with significant catalytic efficiency.

    • Two hybrids based on Keggin polyoxometalates and dinuclear copper(II) complexes: syntheses, structures and electrocatalytic properties

      YAN HOU YING NIU CHUNJING ZHANG HAIJUN PANG HUIYUAN MA

      More Details Abstract Fulltext PDF

      By introducing mixed-ligands en and ox, Cu²⁺ and different polyoxotungstates as synthons, two new polyoxotungstate-based inorganic-organic hybrid compounds {[Cu₂ (en) &#8322 (ox)][HPW₁₂O₄₀]} · (en) ₂ · 2H₂O (1) and {[Cu₂ (en) ₂ (ox)] [H₃BW₁₂O₄₀]} · (en) ₂ · 2H₂O (2) (en = ethylenediamine and ox = oxalate), were obtained in identical hydrothermal conditions and further characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. Structural analyses revealed that both compounds are isostructural, and show one-dimensional (1D) chain constructed by [XW₁₂O₄₀]n− (X = P 1, B 2) Keggin-type polyoxoanions and [Cu₂ (en) ₂ (ox)] ²⁺ dinuclear copper subunits. The electrochemical experiments indicated that 1-based carbon paste electrode possesses high catalytic efficiency and selectivity towards reduction of H₂O₂, and thus 1 has potential to detect H₂O₂.

    • The noncovalent complexes of nido-C₄B₂H₆ with H₂O, CH₃ OH and NH₃ Lewis bases: A Theoretical study

      NAHID ZARE ABEDIEN ZABARDASTI

      More Details Abstract Fulltext PDF

      Quantum chemical calculations at the MP2/6-311++G(2d,2p) level of theory were used to examine the complexes resulting from the interactions between C₄B₂H₆ and HY Lewis bases (HY = NH₃, H₂O, and CH₃ OH molecules). Four different directional geometries could be obtained for C₄B₂H₆ -HY complexes.The complexes with conformation A had (B11-H12· · · H-Y) dihydrogen bond and C-Hmeta. . .YH hydrogen bondinteractions. In structure B, HY from the pentagonal basal plane interacted with carborane molecule. In conformation C, HY had DHB and HB interactions with peripheral B-H and C-Hortho bonds of the carboranebackbone. Finally, conformation D had only hydrogen bond interaction between HY with C-Hmeta bonds of the C₄B₂H₆. Among all the complexes resulting from the interaction of HY with C₄B₂H₆, the greatest interaction energy belonged to the complexes with configurations B. The Bader’s Quantum Theory of Atoms in Molecules (QTAIM) was used to analyze the optimized complexes. Molecular electrostatic potentials (MEP), vibrational frequencies and molecular energies (HOMO and LUMO) were also calculated for these clusters.

  • Journal of Chemical Sciences | News

© 2017 Indian Academy of Sciences, Bengaluru.