pp 515-531 Regular Article
ANAMIKA SINGH GAUR ANSHU BHARDWAJ ARUN SHARMA LIJO JOHN M RAM VIVEK NEHA TRIPATHI PRASAD V BHARATAM RAKESH KUMAR SRIDHARA JANARDHAN ABHAYSINH MORI ANIRBAN BANERJI ANDREW M LYNN ANMOL J HEMROM ANURAG PASSI APARNA SINGH ASHEESH KUMAR CHARUVAKA MUVVA CHINMAI MADHURI CHINMAYEE CHOUDHURY D ARUN KUMAR DEEPAK PANDIT DEEPAK R BHARTI DEVESH KUMAR ER AZHAGIYA SINGAM GAJENDRA PS RAGHAVA HARI SAILAJA HARISH JANGRA KAAMINI RAITHATHA KARUNAKAR TANNEERU KUMARDEEP CHAUDHARY M KARTHIKEYAN M PRASANTHI NANDAN KUMAR N YEDUKONDALU NEERAJ K RAJPUT P SRI SARANYA PANKAJ NARANG PRASUN DUTTA R VENKATA KRISHNAN REETU SHARMA R SRINITHI RUCHI MISHRA S HEMASRI SANDEEP SINGH SUBRAMANIAN VENKATESAN SURESH KUMAR UCA JALEEL VIJAY KHEDKAR YOGESH JOSHI G NARAHARI SASTRY
Molecular Property Diagnostic Suite (MPDSTB) is a web tool (http://mpds.osdd.net) designed to assist the in silico drug discovery attempts towards Mycobacterium tuberculosis (Mtb). (MPDSTB) tool has nine modules which are classified into data library (1–3), data processing (4–5) and data analysis (6–9). Module 1 is a repository of literature and related information available on the Mtb. Module 2 deals with the protein targetanalysis of the chosen disease area. Module 3 is the compound library consisting of 110.31 million unique molecules generated from public domain databases and custom designed search tools. Module 4 contains toolsfor chemical file format conversions and 2D to 3D coordinate conversions. Module 5 helps in calculating the molecular descriptors. Module 6 specifically handles QSAR model development tools using descriptors generated in the Module 5. Module 7 integrates the AutoDock Vina algorithm for docking, while module 8 provides screening filters. Module 9 provides the necessary visualization tools for both small and large molecules. The workflow-based open source web portal,(MPDSTB) 1.0.1 can be a potential enabler for scientists engaged in drug discovery in general and in anti-TB research in particular.
pp 533-541 Regular Article
Effect of external perturbation (in terms of external electric field and solvents) on the stability of lysine-aspartic acid salt bridge was analyzed by density functional theory. Because of solvation, interaction energy in the aqueous phase is much lower as compared to gas phase. Interaction energy as well as stability (measured in terms of global hardness, HOMO energy and total electronic energy) are observed to be sensitive towards the strength and direction of the applied electric field. Gap between HOMO energy of the acids and salt bridge also points towards the feasibility of hydrogen bonding.
pp 543-552 Regular Article
The bonding and structures of lithium ion carbonyl complexes, Li⁺·(CO)1−3, were studied at the CCSD and MP2 levels of theories. A linear configuration is formed for the global minimum of the Li⁺·COand Li⁺·(CO)2 complexes with bond dissociation energies of 13.7 and 12.4 kcal mol−1, respectively. For the Li⁺·(CO)3 complex, a trigonal planar geometry is formed for the global minimum with a bond dissociation energy of 9.7 kcal mol−1.The computed sequential bond dissociation energies of Li⁺·(CO)n (n=1–3) complexes agreed with the experimental findings, in which the electrostatic energy plays an important role in the obtained trend.
pp 553-559 Regular Article
The silver(I) and copper(II)-imidazolium carboxylate coordination assemblies were derived from the reaction between corresponding carboxylic acid ligands and metal salts. These new metal derivatives depict a novel structural motif with variable chemical and thermal properties. These metal complexes act as potentialcatalysts in Ullmann coupling reactions. The imidazolium linker present in these complexes plays a role as both ligand and counter ion to balance the metal charge.
pp 561-571 Regular Aricle
A series of Cp*Rh and Cp*Ir complexes of various nitrogen and oxygen donor ligands were synthesized and characterized. Mono, bi and tetradentate ligands were used to synthesize mononuclear and dinuclear complexes. Schiff base derivatives of picolinic hydrazine and 5-aminoquinoline were used in thesynthesis of complexes 1–8. Among the ligands used for complexation, L1 and L2 act as bidentate, L3 as monodentate and L4 as tetradentate in forming the corresponding complexes. All the complexes were characterized by spectroscopic techniques and the structures of complexes 2, 3, 5 and 7 were unambiguouslycharacterized by single crystal X-ray crystallography. Complexes 2 and 7 were found to have π-π stacking interactions and solvent to complex interactions, respectively. Metal-mediated deprotonation of N-H and monodentate binding of nitrogen are attributed to the formation of neutral complexes whereas ionic complexes are formed by (N,O) bonding.
pp 573-578 Regular Article
A new polyoxometalate-based 3D porous framework with inorganic molecular nanocage unit, (H₂dap)[K(H₂O)₂ (V₁₀O₂₈)₀.₅] (1) (dap = 1,2-diaminopropane), has been synthesized and characterized by routine methods. In 1, the decavanadate clusters, as twelve-dentate connectors, link eight potassium ions to form a 3D porous framework with inorganic molecular cage units. There are two dap ligand molecules occupying in each inorganic molecular cage. Furthermore, the electrochemical properties of 1 were studied, which indicate that 1 has a good electrocatalytic activity towards reduction of iodate (IO⁻ ₃ ) ascribed to the V-center.
pp 579-587 Regular Article
Host-guest inclusion complex of an ionic solid (tetrabutyl ammonium iodide) with α- and β- cyclodextrin has been explored by various physicochemical and spectroscopic methods. Surface tension and conductivity studies indicated 1:1 stoichiometry of the inclusion complexes and ¹H NMR and FT-IR studies substantiated the inclusion phenomenon. Density, viscosity and refractive index studies characterized the interactions of cyclodextrin with tetrabutyl ammonium iodide, which also indicated greater extent of encapsulation in β-cyclodextrin than in α-cyclodextrin. Hydrophobic effect, structural effect, electrostatic force and H-bonding interactions were mainly exploited to explicate the formation of inclusion complex.
pp 589-599 Regular Article
A series of ammonia treated Mo/Activated Carbon (AC) catalysts were synthesized by wet impregnation method by nominal incorporation of 5, 10 and 15 wt% of molybdenum. The calcined catalysts (500◦C, 4 h, N₂ flow) were subjected to a stepwise ammonia treatment at temperatures from 25 up to 700◦C. This work reports for the first time, ammonia treated different loadings of Mo on DARCO mesoporous activated carbon for CO hydrogenation reaction. These catalysts were tested in the reaction temperature range of 250–325◦C, 7 MPa and 12000/h (GHSV for reactor volume 0.5 mL). At 250◦C, all the catalysts showed total oxygenate selectivity of ∼50%, mainly methanol. At 325◦C, total oxygenate selectivity of 16.5% with 18% CO conversion was obtained on 10Mo-N/AC. The result of alcohol distribution revealed high selectivity to propanol (39%) over methanol (34%) at 325◦C on 10Mo-N/AC which highlights its unique catalytic behavior in CO hydrogenation. Further, 10MoO3/AC catalyst, with no treatment of ammonia, showed only 4% of CO conversion with 96% hydrocarbon selectivity. Only 0.5% of CO conversion was observed on AC itself at 325◦C. The improved oxygenates selectivity on 10Mo-N/AC was associated with Moδ+ sites on AC generated viaammonolysis.
pp 601-608 Regular Article
SBA-15, KIT-6, SiO₂ supported catalysts with 10% Cu loading have been prepared by impregnation techniques. The prepared catalysts have been characterized by BET technique, X-ray diffraction, Temperature programmed reduction (TPR), XPS and N₂O pulse chemisorption techniques. Dehydrogenation of cyclohexanol has been performed over these catalysts in vapour phase at 523 K. SBA-15 and KIT-6 supported copper catalystsshowed higher activity than SiO₂ supported Cu catalyst in dehydrogenation of cyclohexanol, which can be attributed to better Cu dispersion, small copper particle size and more number of Cu active species presented on the surface of mesoporous supported catalysts.
pp 609-622 Regular Article
Binary complexes of Cu(II), Ni(II) and Co(II) were synthesized using two novel Schiff bases L₁ = 2-(-(benzothiazol-6-ylimino)methyl)-4-chlorophenol (BTEMCP), L₂= 2-(-(benzothiazol-6-ylimino) methyl)-4-nitrophenol. The Schiff bases and metal complexes were characterized by analytical and spectral methods like elemental analysis, Mass, ¹H-NMR, ¹³ C-NMR, UV-Vis, IR, ESR, SEM, EDX, XRD and magnetic susceptibility measurements. From the analytical data, square planar geometry has been proposed for all themetal complexes. The binding interaction between the metal complexes and DNA was investigated by means of electronic absorption, fluorescence spectroscopy and viscosity measurements. The DNA cleavage ability ofthe metal complexes was also evaluated by agarose gel electrophoresis method. These studies revealed that the complexes showed an intercalative mode of binding to CT DNA and also effectively cleaved the supercoiledpBR DNA. The synthesised compounds were evaluated for in vitro antibacterial activity against Gram positive and Gram negative bacteria, and found that the metal complexes showed more potent biocidal activity than theSchiff bases.
pp 623-636 Regular Article
In our earlier studies, we have shown that the introduction of amino moieties at carboxylic acid of 4,5-diarylthiophene-2-carboxylic acid significantly improved the anti-inflammatory activity of the compound against the standard drug diclofenac sodium. In the present study, we have synthesized new derivatives of 4,5- diarylthiophene-2-carboxylic acid by modifying the hydroxyl group of the phenyl ring and carboxylic acid group of the thiophene ring.Aseries of novel 4,5-diarylthiophene-2-carboxylic acid derivatives containing bis-allyloxyand hydroxypropoxy with methyl or ethyl ester moieties were synthesized, characterized and subsequently evaluated for anti-inflammatory and antioxidant property. Among the novel compounds, the inhibition of bovineserum albumin denaturation assay revealed that the compound 4,5-bis(4-(3-hydroxypropoxy)phenyl)thiophene- 2-carboxylic acid (15) and ethyl ester (13) having anti-inflammatory activity better than the standard drugdiclofenac sodium. The antioxidant screening showing 4,5-bis(4-(allyloxy)phenyl)thiophene-2-carboxylic acid (10), 4,5-bis(4-(3-hydroxypropoxy)phenyl)thiophene-2-carboxylic acid methyl ester (11) and 4,5-bis(4-(3- hydroxypropoxy)phenyl)thiophene-2-carboxylic acid ethyl ester (13) exhibited a slightly moderate antioxidant activity than standard ascorbic acid. Molecular docking analysis was performed for the synthesized compounds with the cyclooxygenase-2 (COX-2) receptor (PDB 1D: 1PXX). Docking studies revealed that all the synthesised compounds exhibit greater binding affinity than the standard drug. Particularly, the compound ethyl 4,5-bis(4- (allyloxy)phenyl)thiophene-2-carboxylate (8) and allyl 4,5-bis(4-(allyloxy)phenyl)thiophene-2-carboxylate (9) having high free energy binding of −10.40 and −10.48 Kcal/mol, respectively.
pp 637-645 Regular Article
Different spectroscopic methods have been applied to investigate the chromic acid oxidation of acetaldehyde in aqueous media, catalysed by surfactants. Three representative heteroaromatic nitrogen base promoters, 2-picolinic acid (PA), 2,2’-bipyridine (bpy) and 1,10-phenanthroline (phen), have been associated along with surfactants as promoters to the kinetic study. Comparative studies of unpromoted and promoted reactions invoked that 2,2’-bipyridine produced maximum rate enhancement. The mechanism of the reaction path has been proposed with the help of kinetic results and spectroscopic studies. The observed net enhancementof rate effects has been explained with scientific manipulations and data obtained. The combination of TX-100 and1,10-phenanthroline is found to be most effective for acetaldehyde oxidation.
pp 647-656 Regular Article
Novel bis(pyrrole-benzimidazole) (PYBI) conjugates were investigated as colorimetric anion recognition motif by employing multiple donor sites. In this regard, PYBI derivatives where pyrrole unit is connected to the C2 position of benzimidazole via its α-position were synthesized and their anion recognitionbehavior were evaluated by UV-Vis, fluorescence and 1H NMR spectroscopy. PYBI selectively interacts with fluoride ion, whereas introduction of nitro group on the benzimidazole moiety enhances the binding affinity by at least one order, albeit at the expense of the selectivity. Bridging of two PYBIs led to interesting cooperative effect between the two subunits, which gets enhanced upon changing the spacer between the two from nonconjugatingtype (sp3-C) to conjugating one (quinoxaline). This also affects the way they interact with anions, with the latter moiety displaying very interesting stepwise double deprotonation of benzimidazole protons upon addition of fluoride ions with strong colorimetric as well as fluorometric response. Further, acidity of the H-bond donor sites was found to play pivotal role in the anion complexation mechanism and selectivity.