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      Volume 125, Issue 1

      January 2013,   pages  7-211

    • General Editorial on Publication Ethics

      S S Krishnamurthy

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    • Redundant internal coordinates, compliance constants and non-bonded interactions - some new insights

      Moumita Majumder Sadasivam Manogaran

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      A long standing problem in normal mode analysis is identifying the right internal coordinates given only the cartesian coordinates, the masses of the atoms and the cartesian force constants without using any other additional chemical information. A possible solution is suggested here as drawing the normal modes obtained from the mass weighted cartesian force constant matrix and identifying the correct bonds and angles from the normal mode pictures. If chosen properly, the internal coordinates will have minimum mixing in the normal mode representation. This can in principle lead to an automation algorithm. A complete basis of internal coordinates is defined as the minimum number of valence internal coordinates that describe all the normal modes as completely as possible. It was shown in the literature that the relaxed force constants could be used as a measure of bond order in all atom-atom distance coordinates. Some of the bonded and non-bonded atom pairs can have similar values of the relaxed force constants and hence to use the relaxed force constant as a measure of bond order we need to separate the bonded pairs from the non-bonded ones. This needs extra chemical information of which pairs are bonded. The new definition of complete basis of non-redundant valence internal coordinates helps to identify the bonded pairs effectively without extra information. The hydrogen bonded water clusters (H2O)$_n$, n = 2-6, methane dimer and methane-water complex are used as examples to verify that the relaxed force constants of bonded pairs are indeed a measure of bond order.

    • Synthesis, photophysical and preliminary investigation of the dye-sensitized solar cells properties of functionalized anthracenyl-based bipyridyl and phenanthrolyl Ru(II) complexes

      Adewale O Adeloye Peter A Ajibade Frances R Cummings Lukas J Le Roux Sampson N Mamphweli Edson L Meyer

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      Four new amphiphilic ligands: 4-(2,3-dimethylacrylic acid)-2,2'-bipyridine (L1), 4-(9-anthracenyl-10-(2,3-dimethylacrylic acid)-2,2'-bipyridine (L2), 5-(2,3-dimethylacrylic acid)-1,10-phenanthroline (L3) and 5-(9-anthracenyl-10-(2,3-dimethylacrylic acid)-1,10-phenanthroline (L4), with their corresponding homonuclear ruthenium(II) complexes formulated as cis-[Ru-(L1)3(PF6)2] (C1), cis-[Ru-(L2)3(PF6)2] (C2), cis-[Ru-(L3)3(PF6)2] (C3) and cis-[Ru-(L4)3(PF6)2] (C4), have been synthesized and characterized by elemental analysis, 1H- and 13C- NMR, FT-IR, UV-Vis and photoluminescence spectroscopy. The complexes exhibit broad and intense metal-to-ligand charge transfer (MLCT) transition bands in the visible region (400-700 nm), and red light emitting properties at room temperature. By comparison however, complexes C1 and C2 bipyridine moiety gave lower molar absorptivity coefficient at relatively similar wavelength characteristics (410-520 nm) when compared to C3 and C4 with phenanthroline based molecules. Cyclic voltammograms of the complexes revealed complex C4 with most reduction potential which might be due to increase in the conjugation of the anthracene functionalized units. Preliminary investigation of the solar cell efficiency of the complexes on TiO2 nanocrystalline films gave the best result with efficiency of 0.103% for C1 under illumination at 1000 W/m2 AM 1.5. Electrochemical impedance spectroscopy (EIS) technique however, revealed the charge transfer resistances (Rct) of the electrons on the TiO2 semiconductor.

    • Synthesis and two-photon absorption property of new 𝜋-conjugated donor-acceptor polymers carrying different heteroaromatics

      M S Sunitha K A Vishnumurthy A V Adhikari

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      In this communication, we report the synthesis of three newly designed fluorescent polymers P1-P3, starting from simple thiophene derivatives through precursor polyhydrazide route. The new polymers, carrying donor and acceptor heterocyclic moieties with different spacer groups were found to be thermally stable and good of nonlinear optical (NLO) materials with two photon absorption property. The structures of newly synthesized monomers and polymers were confirmed by FTIR, NMR spectral and elemental analyses. Further, polymers were characterized by GPC and TGA studies. Their linear optical and electrochemical properties were evaluated by UV-vis, fluorescence spectroscopic and cyclic voltammetric (CV) studies, respectively, whereas their NLO properties were studied by Z-scan technique using Nd: YAG laser at 532 nm with 7 ns pulse. The electrochemical band gap of P1-P3 was determined to be 1.98, 1.91 and 2.05 eV, respectively. The NLO results reveal that polymers P1-P3 show good optical limiting property with TPA coefficient values $2.9 \times 10^{−11}$ m/W, $8.0 \times 10^{−11}$ m/W and $1.4 \times 10^{−11}$ m/W, respectively.

    • Ferrocene-based Lewis acids and Lewis pairs: Synthesis and structural characterization

      Pagidi Sudhakar Pakkirisamy Thilagar

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      Optically active Lewis acids and Lewis pairs were synthesized and characterized by multinuclear NMR, UV/Vis spectroscopy and elemental analysis. Optical rotation measurements were carried out and the absolute configuration of the new chiral molecules confirmed by single crystal X-ray diffraction.

    • Osmium and cobalt complexes incorporating facially coordinated N,N,O donor azo-imine ligands: Redox and catalytic properties

      Poulami Pattanayak Debprasad Patra Jahar Lal Pratihar Andrew Burrows Mary F Mahon Surajit Chattopadhyay

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      Reactions of 1-{[2-(arylazo)phenyl]iminomethyl}-2-phenol, HL [where H represents the dissociable phenolic protons of ligands and aryl groups of HL are C6H5 (HL1), 𝑝-CH3C6H5 (HL2), 𝑝-ClC6H5 (HL3)] with Os(H)(CO)(Br)(PPh3)3 in toluene and with Co(ClO4)3.6H2O in methanol afforded new facially coordinated complexes of composition [(L)Os(CO)(Br)(PPh3)] and [(L)2Co]ClO4. The anionic ligand (L), binds the metal in tridentate (N, N, O) manner in [(L)Os(CO)(Br)(PPh3)] and [(L)2Co]ClO4 complexes. All the Os(II) and Co(III) complexes are diamagnetic and show characteristic 1H NMR signals and intense MLCT transitions in the visible region. The cyclic voltammograms exhibited one quasi reversible oxidative response near 0.10 V vs SCE for [(L)Os(CO)(Br)(PPh3)] and [(L)2Co]ClO4 complexes displayed serial reductive responses within −0.06 to −1.61 V vs SCE. Single point DFT calculation was carried out to examine the nature of redox orbitals. Conversion of ketones to corresponding alcohols has been studied using [(L)Os(CO)(Br)(PPh3)] as catalyst.

    • Structural and catalytic properties of a novel vanadium containing solid core mesoporous silica shell catalysts for gas phase oxidation reaction

      N Venkatathri Vijayamohanan K Pillai A Rajini M Nooka Raju I A K Reddy

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      A novel vanadium containing solid core mesoporous silica shell catalyst was synthesized with different Si/V ratios by sol-gel method under neutral conditions. The synthesized materials were characterized by various techniques and gas phase diphenyl methane oxidation reaction. The mesoporosity combined with microporosity are formed by incorporation of octadecyltrichloro silane and triethylamine in the catalyst and it was found out from E-DAX and BET—surface area analysis. The material was found to be nanocrystalline. Vanadium is present as V4+ species in as-synthesized samples and convert to V$^{5+}$ on calcination. Most of the vanadium is present in tetrahedral or square pyramidal environment. Incorporation of vanadium in silica framework was confirmed by 29Si MAS NMR analysis. Among the various vanadium containing solid core mesoporous silica shell catalysts, the Si/V =100 ratio exhibited maximum efficiency towards diphenyl methane to benzophenone gas phase reaction. The optimum condition required for maximum conversion and selectivity was found out from the catalytic studies.

    • Super acid catalysed sequential hydrolysis/cycloisomerization of 𝑜-(acetylenic)benzamides under microwave condition: Synthesis, antinociceptive and antiinflammatory activity of substituted isocoumarins

      Chandrasekaran Praveen P Dheenkumar P T Perumal

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      Synthesis of isocoumarins and related compounds via triflic acid promoted hydrolysis/cyclization sequence of 2-(alkynyl)benzamides under microwave condition was achieved. The substrate scope of the reaction was broad to include not only aromatic but also polyaromatic and heteroaromatic motifs, thus highlighting the significance of this methodology. One-pot operation, short reaction time, good chemical yields and excellent regioselectivity are the advantages of this protocol. All the synthesized compounds were evaluated for their antinociceptive and antiinflammatory activities using in vivo rodent models.

    • An efficient synthesis and biological study of substituted 8-chloro-5-methoxy/8-chloro-4H-1,4-benzothiazines, their sulphones and ribofuranosides

      Nishidha Khandelwal Abhilasha Naveen Gautam D C Gautam

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      8-Chloro-5-methoxy/8-chloro-4H-1,4-benzothiazines were synthesized by condensation followed by oxidative cyclisation of 2-amino-6-chloro-3-methoxy/2-amino-3-chlorobenzenethiol with 𝛽-diketones/𝛽-ketoesters in the presence of dimethyl sulphoxide. By treating 4H-1,4-benzothiazines with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-benzothiazine-1,1-dioxides (sulphones) were synthesized. The 4H-1,4-benzothiazines have also been used as a base to prepare ribofuranosides by the reaction with 𝛽-D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antimicrobial and anthelmintic activity.

    • Novel multicomponent synthesis of 2,9-dihydro-9-methyl-2-oxo-4-aryl- 1𝐻-pyrido[2,3-𝑏]indole-3-carbonitrile compounds

      Saman Damavandi Reza Sandaroos

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      Novel multicomponent approach for the synthesis of 2,9-dihydro-2-oxo-4-aryl-1𝐻-pyrido[2,3-𝑏]indole-3-carbonitrile derivatives via one-pot cyclocondensation reaction of substituted (triethoxymethyl) arene, 1-methyl-1𝐻-indol-2-ol and cyanoacetamide in the presence of silica supported ionic liquid [pmim]HSO$_{4SiO2}$ (silica-supported 1-methyl-3-(triethoxysilylpropyl)imidazolium hydrogensulphate) has been reported.

    • An eco-sustainable green approach for the synthesis of propargylamines using LiOTf as a reusable catalyst under solvent-free condition

      Someshwar D Dindulkar Baek Kwan Kwon Taek Lim Yeon Tae Jeong

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      An efficient process has been developed for the synthesis of propargylamines via a threecomponent coupling reaction of aldehyde, secondary alicyclic amine and alkyne (A3) under solvent-free condition using lithium triflate (LiOTf) as expeditious reusable catalyst. This one-pot transformation generates one C-C and one C-N bond, which presumably proceeds by lithium acetylide as well as formation of iminium ion in situ and then undergoes nucleophilic addition to the iminium ion to give the propargyl amine. The solventfree condition, easy recovery of the catalyst, simple, user-friendly and quantitative yield in short time renders the protocol economic and reasonable.

    • PEG-SO3H as a catalyst in aqueous media: A simple, proficient and green approach for the synthesis of quinoline derivatives

      M A Nasseri S A Alavi B Zakerinasab

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      A convenient and efficient method was developed for the synthesis of quinolines, an important class of potentially bioactive compounds. The quinoline derivatives were prepared in water, an excellent solvent in terms of environmental impact and with reduced waste production. PEG-SO3H effectively catalysed the one-pot synthesis of quinolines by the condensation of 𝑜-aminoaryl ketones and carbonyl compound with high yields (75-95%). The compounds were isolated by simple filtration in a high purity form.

    • New bispyrazoline derivatives built around aliphatic chains: Synthesis, characterization and antimicrobial studies

      Mohamad Yusuf Payal Jain

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      The bispyrazolines 3a-3h built around the alkyl chains of varying lengths have been synthesized from the cyclization reactions of bischalcones with phenyl hydrazine. The bischalcones 2a-2h were obtained from the Claisen-Schmidt reactions of acetophenone with various bisaldehydes 1a-1h. The intermediate bischalcones and final bisheterocyclic compounds have been characterized by means of IR, 1H-NMR, 13C-NMR, Mass (ESI) and elemental analysis. The antibacterial and antifungal activities of the synthesized compounds were also evaluated against the Klubsellia pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillius subtilis and Aspergillius janus, Aspergillus niger and Pencillium glabrum, respectively. The antimicrobial behaviour of the bispyrazolines 3a-3h is found to be dependent on the length of internal spacer unit.

    • Synthesis of 2-(3-methyl-2-oxoquinoxalin-1(2𝐻)-yl)acetamide-based azetidinone derivatives as potent antibacterial and antifungal agents

      Shiv Kumar Nitin Kumar Sushma Drabu Md Akram Minhaj

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      Twelve compounds belonging to series N-[3-chloro-2-oxo-4-(substituted)phenylazetidin-1-yl]-2-(3-methyl-2-oxoquinoxalin-1(2𝐻)-yl)acetamide (5a-l) were synthesized. These compounds were evaluated for their in vitro antibacterial against E. coli, S. aureus, K. pneumoniae, P. aeruginosa and antifungal activity against C. albicans, A. niger and A. flavus by cup-plate method. Structures of all the newly synthesized compounds were confirmed by their spectral data interpretation. Compound 5g having 𝑝-dimethylaminophenyl group on 4-position of azetidinone ring attached to N-atom of acetamido group on 1-position of 3-methyl-1𝐻-quinoxaline-2-one, was found to be active against all the bacterial and fungal strains under investigation.

    • Synthesis, photophysical property study of novel fluorescent 4-(1,3-benzoxazol-2-yl)-2-phenylnaphtho[1,2-𝑑][1,3]oxazole derivatives and their antimicrobial activity

      Kiran R Phatangare Bhushan N Borse Vikas S Padalkar Vikas S Patil Vinod D Gupta Prashant G Umape N Sekar

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      A series of 4-(1,3-benzoxazol-2-yl)-2-phenylnaphtho[1,2-𝑑][1,3]oxazole derivatives have been synthesized from intermediate 1-amino-3-(1,3-benzoxazol-2-yl)naphthalen-2-ol. This intermediate was obtained by coupling 3-(1,3-benzoxazol-2-yl)naphthalen-2-ol with 4-sulphobenzenediazonium chloride followed by reduction with sodium dithionate in water at pH 8-9. 3-(1,3-benzoxazol-2-yl)naphthalen-2-ol was synthesized from 3-hydroxynaphthalene-2-carboxylic acid and 2-amino phenol in the presence of PCl3 in chlorobenzene at 130-135°C. All these compounds were characterized by FT-IR, 1H NMR, mass spectral and elemental analysis. The synthesized compounds are fluorescent which absorbs in the range of 296 to 332 nm while emits in the ranges of 368 to 404 nm with excellent quantum yield. All compounds were evaluated for in vitro antibacterial activities against Escherichia coli and Staphylococcus aureus strains and in vitro antifungal activity against Candida albicans and Aspergillus niger strains by using serial dilution method.

    • Nano indium oxide as a recyclable catalyst for the synthesis of arylaminotetrazoles

      Siavash Bahari Mehdi Ahmadi Sabegh

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      Nano indium oxide is an effective heterogeneous catalyst for the reaction between aryl cyanamides and sodium azide to synthesize the arylaminotetrazoles in good yields. This method has advantages of high yields, simple methodology, short reaction times and easy work-up. The catalyst can be recovered and reused in good yields.

    • Thiamine hydrochloride: An efficient catalyst for one-pot synthesis of quinoxaline derivatives at ambient temperature

      Omprakash B Pawar Fulchand R Chavan Venkat S Suryawanshi Vishnu S Shinde Narayan D Shinde

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      Quinoxaline derivatives have been synthesized in high to excellent yields in the presence of thiamine hydrochloride (VB1) as an inexpensive, non-toxic and metal ion free catalyst at ambient temperature.

    • Synthesis and evaluation of some bioactive compounds having oxygen and nitrogen heteroatom

      Poonam Yadav Nalini V Purohit

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      Some new 3,4-disubstituted isocoumarins were synthesized having bioactive pyrazole molecule at 3rd position of isocoumarin moiety (5a,b), from isocoumarin -3- carboxylic acid hydrazide (4a,b) followed by cyclization with acetyl acetone. A series of isocoumarin derivative having Schiff base as lateral side chain at 3rd position of isocoumarin moiety were also synthesized (7a,b), by condensing isocoumarin acid hydrazide and benzaldehyde derivative followed by dehydration. The chemical structures of all the compounds were determined by analytical and spectral method. The lead compounds were screened for antimicrobial and analgesic activities.

    • A Cu (NO3)2.3H2O catalysed facile synthesis of substituted 4(3H)-quinazolinones and benzimidazoles

      G A N K Durgareddy R Ravikumar S Ravi Srinivas R Adapa

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      One pot synthesis of alkyl, aryl, heteroaryl mono(2)substituted 4(3H)-quinazolinones and 2-aryl or heteroaryl, 1-arylmethyl or heteroarylmethyl -1H-benzimidazoles using a water soluble Cu (NO3)2.3H2O catalyst at room/ambient temperature in excellent yield.

    • Comparison of anti amoebic activity of stereoisomeric diamino and monoamino pregnene alkaloids and their N-methylated analogs

      Raj M Vaid K K Bhutani

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      The steroidal alkaloid 3𝛽, 20𝛼-diamino-pregn-5-ene (kurchamine) obtained from the stem bark of Holarrhena antidysenterica is reported to have appreciable amoebicidal activity. Its three stereoisomers namely 3𝛼, 20𝛽-diamino-pregn-5-ene, 3𝛽,20𝛽-diamino-pregn-5-ene and 3𝛼, 20𝛼-diamino-pregn-5-ene and their intermediate stereoisomeric monoamino pregnene alkaloids namely 3𝛽-amino-pregn-5-ene-20-one, 3𝛼-aminopregn-5-ene-20-one, 20𝛼-amino-pregn-5-ene-3𝛽-ol, 20𝛽-amino-pregn-5-ene-3𝛽-ol were synthesized. The natural stereoisomer and synthesized diamino and monoamino stereoisomers were N-methylated and all the compounds were evaluated for amoebicidal activity comparison. The natural stereoisomer 3𝛽,20𝛼-diamino-pregn-5-ene (kurchamine) was found to be superior than other stereoisomers and N-methylation was found to have insignificant effect on amoebicidal activity of stereoisomers.

    • Chemistry and antifungal potential of Alantolides from Inula racemosa H

      Dalvir Kataria K K Chahal

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      Alantolactone and isoalantolactone were isolated from powdered roots of Inula racemosa H. using Soxhlet extraction followed by the column chromatography. Pyrazolines of alantolactone and isoalantolactone were synthesized using diazomethane, diazoethane and diazopropane. The structure elucidation of the compounds were carried out using IR and 1H NMR spectroscopic techniques. All the compounds were screened in vitro for their antifungal potential at various concentrations against Alternaria brassicae and Penicillium italicum using spore germination inhibition technique and against $Rhizoctonia solani by poisoned food technique. All the compounds exhibited fairly good fungitoxicity against the test fungi with ED50 values of less than 500 𝜇g mL-1.

    • Preparation of amphiphilic block copolymer containing triazene moieties and fluorescence study

      Emil C Buruiana Andreea L Chibac Violeta Melinte Tinca Buruiana

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      The present study describes the synthesis via microwave accelerated reversible additionfragmentation chain transfer (RAFT) polymerization of an amphiphilic block copolymer poly(acrylic acid)-b-poly(dodecylacrylamide-co-1-(phenyl)-3-(2-methacryloyloxyethyl carbamoyloxyethyl)-3-methyltriazene-1) [PAA-b-(PDA-co-PUMA-T)]. The structure and the chemical composition of the block copolymer were confirmed by spectral/thermal analysis. The photoreactivity of the triazene sequences from PAA-b-(PDA-co-PUMA-T) was quantified by UV/vis irradiation in chloroform/dimethylformamide solutions and in thin film, indicating that the solvent polarity modifies with an order of magnitude the rate constant values. The lower rate constant in film state ($kfilm = 1.3 \times 10^{−3}$ s-1), shows that the higher mobility of polymeric chains in solution allow a more rapid orientation, favourable to the triazene bond cleavage. The capability of block copolymer to form micelles in aqueous environment and implicitly, its critical micelle concentration (CMC) was evidenced through fluorescence measurements using pyrene probe (10-6 M), the CMC value being of $4.64 \times 10^{−3}$ g L-1 PAA-𝑏-(PDA-$co$-PUMA-T) ($3.27 \times 10^{−7}$ M). Experiments of fluorescence quenching with various metal cations (UO$^{2+}_2$, Fe2+, Fe3+, Ni2+, Cu2+, Co2+, Pb2+ and Hg2+) suggested that such a block copolymer could find applications as fluorescence-based chemosensor for the detection of iron cations in homogeneous organic solutions or aqueous environments by thin films.

    • Synthesis of novel nanostructured chiral poly(amide-imide)s containing dopamine and natural amino acids

      Shadpour Mallakpour Amin Zadehnazari

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      Four new thermally stable and optically active poly(amide-imide)s (PAI)s with good inherent viscosities were synthesized from the direct polycondensation reaction of N,N'-(pyromellitoyl)-bis-L-𝛼-amino acids with 3,5-diamino-N-(3,4-dihydroxy-phen-ethyl)benzamide in a medium consisting of a molten salt, tetrabutylammonium bromide, and triphenyl phosphite as the activator. The polymerization reactions produced a series of novel PAIs containing dopamine segment in the side chain in high yield with inherent viscosities between 0.33 and 0.49 dL/g. The obtained polymers were typically characterized by means of FT-IR, 1HNMR spectroscopy, elemental analyses, powder X-ray diffraction, field emission scanning electronmicroscopy, inherent viscosity, and solubility tests. Thermal properties and flame retardant behaviour of the PAIs were also investigated using thermal gravimetric analysis (TGA and DTG) and limiting oxygen index (LOI). Data obtained by thermal analysis revealed that these polymers showed good thermal stability. Furthermore, high char yield in TGA and good LOI values indicated that the obtained polymers were capable of exhibiting good flame retardant properties.

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