Class Of Mono Research Articles

Interaction of pseudohalides copper(II) complexes of hydrazide ligand with DNA: synthesis, spectral characterization, molecular docking simulations and superoxide dismutase activity

A new class of mono- and binuclear complexes [Cu(L)(ClO4)(H2O)] 1, [(Cu)(L)(N3)]2 2, [(Cu)(L)(OCN)]2 3, and [(Cu)(L)(CNS)]2 4, have been synthesized (where HL = (E)-N′-(phenyl(pyridin-2-yl)methylene)thiophene-2-carbohydrazide). All complexes have been characterized by elemental analysis and spectroscopic techniques. The crystalline nature of complexes was investigated by powder X-ray diffraction techniques. Polycrystalline Epr spectra with a well-defined half-field signal of complexes 2–4 suggested the intra exchanged-coupled systems. The electrochemical nature of all complexes was examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The room temperature magnetic moment (μeff = 1.47–1.63 BM) for binuclear complexes reveals the presence of weak antiferromagnetic spin-exchange interactions between copper(II) ions. The geometrical structural index (τ5) suggests that the geometries around copper(II) ion remains distorted square pyramidal in each copper. All synthesized complexes and DNA were simulated by molecular docking to understand the binding of complexes with DNA. The superoxide dismutase activity (SOD) of all complexes was investigated.

Nano-sheets of two-dimensional polymers with dinuclear (arene)ruthenium nodes, synthesised at a liquid/liquid interface

We developed a new class of mono- or few-layered two-dimensional polymers based on dinuclear (arene)ruthenium nodes, obtained by combining the imine condensation with an interfacial chemistry process, and use a modified Langmuir–Schaefer method to transfer them onto solid surfaces. Robust nano-sheets of two-dimensional polymers including dinuclear complexes of heavy ruthenium atoms as nodes were synthesised. These nano-sheets, whose thickness is of a few tens of nanometers, were suspended onto solid porous membranes. Then, they were thoroughly characterised with a combination of local probes, including Raman spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy in imaging and diffraction mode.

Regioselective synthesis and antioxidant activity of a novel class of mono and C2-symmetric bis-1,2,3-triazole and acridinedione grafted macromolecules

An expedient regioselectivesynthesis of novel mono, C2-symmetric bis-triazole and acridinedione bridged macromolecules has been achieved in good yields employing intermolecular Cu(I) catalyzed azide and alkyne click reaction. Synthesis of O-propargyl acridinedione was achieved in three good yielding steps starting from dimedone, while the symmetrical aliphatic and aryl bis-azides were derived from appropriate dibromides in the presence of sodium azide in dry DMF. The synthesized mono and C2-symmetric bis-macromolecules have been elucidated by 1H, 13C, elemental and mass spectroscopic analysis. The antioxidant activity of synthesized compounds has also been investigated.

Fixed bed dynamics of single and multicomponent adsorption of pentane and hexane isomers in ZIF-8

Single, quinary and septenary fixed bed breakthrough experiments of pentane (nC5/iC5) and hexane (nC6/2MP/3MP/23DMB/22DMB) isomers were performed in shaped zeolitic imidazolate metal organic framework ZIF-8. Adsorption equilibrium isotherms for linear nC5 and nC6 were measured from the single component breakthrough curves covering the temperature range between 373 and 473 K and partial pressures up to 50 kPa. The equimolar septenary (nC5/iC5/nC6/2MP/3MP/23DMB/22DMB) and quinary (iC5/2MP/3MP/23DMB/22DMB) studies were performed at the same temperature range and total hydrocarbon pressure of 25 kPa. In the septenary experiments the following sorption hierarchy was observed: nC6 > nC5 > 2MP > 3MP > iC5 > 23DMB > 22DMB. Results also show that the sorption of the linear nC5 and nC6 is dominated by equilibrium in contrast with the sorption of branched isomers which is kinetically controlled. The quinary experiments with C5/C6 branched paraffins evidences the partially separation by classes of mono- and di-branched isomers. The equilibrium data were modelled by the Sips isotherm and the fitted parameters were used to simulate the breakthrough data through a mathematical model developed in a Matlab code using the method of lines (MOL). In the numerical simulations equal diffusivities constants (Dc/rc2) for linear nC5/nC6 were used, being it 0.002 s−1 at 373 K, which is a value 100 times higher than its respective value for the mono-branched isomers iC5, 2MP and 3MP, and 300 times higher than for the di-branched hexane isomer 22DMB. It is also shown the effect of the residence time of the gas regarding the fixed bed separation of the pentane and hexane isomers, from where it is clear that increasing the residence time improves the separation between the compounds.

Synthesis and antimicrobial activity of styryl/pyrrolyl/pyrazolyl sulfonylmethyl-1,3,4-oxadiazolyl amines and styryl/pyrrolyl/pyrazolyl sulfonylmethyl-1,3,4-thiadiazolyl amines

A new class of mono and bis heterocycles - styryl sulfonylmethyl-1,3,4-oxadiazolyl/1,3,4-thiadiazolyl amines, pyrrolyl sulfonylmethyl-1,3,4-oxadiazolyl/1,3,4-thiadiazolyl amines and pyrazolyl sulfonylmethyl-1,3,4-oxadiazolyl/1,3,4-thiadiazolyl amines were prepared from the synthetic intermediate Z-styrylsulfonylacetic acid adopting simple and well versed synthetic methodologies and studied their antimicrobial activity. Amongst all the tested compounds styryl thiadiazole 5c exhibited promising antimicrobial activity against Pseudomonas aeruginosa and Penicillium chrysogenum.

Synthesis of Strained γ-Lactams by Palladium(0)-Catalyzed C(sp(3) )-H Alkenylation and Application to Alkaloid Synthesis.

A variety of strained α-alkylidene-γ-lactams were synthesized by palladium(0)-catalyzed intramolecular C(sp(3) )-H alkenylation from easily accessible acyclic and monocyclic bromoalkene precursors. These lactams are valuable intermediates for accessing various classes of mono- and bicylic alkaloids containing a pyrrolidine ring, as illustrated with the synthesis of an advanced model of the marine natural product plakoridine A and of the indolizidine alkaloid δ-coniceine.

Synthesis of Strained γ‐Lactams by Palladium(0)‐Catalyzed C(sp3)−H Alkenylation and Application to Alkaloid Synthesis

AbstractA variety of strained α‐alkylidene‐γ‐lactams were synthesized by palladium(0)‐catalyzed intramolecular C(sp3)−H alkenylation from easily accessible acyclic and monocyclic bromoalkene precursors. These lactams are valuable intermediates for accessing various classes of mono‐ and bicylic alkaloids containing a pyrrolidine ring, as illustrated with the synthesis of an advanced model of the marine natural product plakoridine A and of the indolizidine alkaloid δ‐coniceine.

Synthesis and anticancer activities of a novel class of mono- and di-metallic Pt(II)(salicylaldiminato)(DMSO or Picolino)Cl complexes.

A series of novel Pt(ii) complexes [cis- and trans-Pt(ii)(salicylaldimine)(DMSO)Cl (), trans-Pt(ii)(salicylaldimine)(4-picoline)Cl (), Pt(ii)(salicylaldimine)Cl (), trans- and cis/trans-Pt2(ii)(salicylaldimine)(DMSO)2Cl2 (), trans-Pt2(ii)(salicylaldimine)(4-picoline)2Cl2 () was synthesized and characterized. The structures of -cis, -trans and were determined using a single crystal X-ray analysis. This class of Pt(ii) complexes has been studied for their in vitro cytotoxicity in multiple human cancer cell lines, including breast (MCF-7), liver (HepG2), lung (A549), colon (HCT116) and cervical (Hela) cancers. -trans, and -trans showed significant cytotoxicity to these cancer cells comparable to cisplatin. A time- and dose-dependent MTT assay revealed that these complexes can suppress cell viability and cell proliferation. Mechanistically these complexes induced pro-apoptotic gene expression such as BAX, PUMA and NOXA and thereby enhanced apoptosis. Moreover, PARP cleavage in a dose-dependent manner indicated their cytotoxic effect against cancer cells. Apoptosis of cancer cells occurred through apoptotic pathways as explained by the cytometry analysis. The DNA unwinding properties of these active Pt(ii) complexes were studied by gel electrophoresis using pBR322 plasmid DNA as a target. Changes in the morphology of cancer cells were also observed upon the addition of -trans, and -trans.

Catalytic reduction of aqueous nitrates by metal supported catalysts on Al particles

Abstract To facilitate the reduction of nitrate to nitrogen in water, a class of mono- or dual-catalyst particles was prepared by loading mono-metals (Cu, Ni) or bimetals (Pd–Cu, Pt–Cu, Au–Cu, and Ru–Cu) on Al particles. The prepared catalyst-loaded Al samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy analysis. Batch kinetic experiments indicate that 0.4%Pd–4%Cu/Al at pH 4.0 resulted in the highest selectivity for nitrogen (N2). Kinetic studies reveal that nitrate can be first reduced to nitrite on the Al and Cu surface at a relatively slow rate and subsequently was rapidly reduced to nitrogen on the noble metal surface and to ammonia on the Al and Cu surface. The selectivity for nitrogen formation can be influenced by the type of metals deposited and the concentration of intermediate nitrite and atomic hydrogen adsorbed on the Pd surface.

ChemInform Abstract: Synthesis and Antioxidant Activity of a New Class of Mono‐ and Bis‐heterocycles.

AbstractNovel highly functionalized mono‐ and bis‐heterocycles (VI)—(XI) are synthesized and tested for their antioxidant properties.

Synthesis and Antioxidant Activity of a New Class of Mono‐ and Bis‐Heterocycles

A new class of mono- and bis-heterocycles, 2-arylsulfonylaminosulfonylmethyl-5-styrylsulfonylmethyloxadiazoles, pyrazolyl oxadiazoles, and isoxazolyl oxadiazoles, were synthesized and tested for their antioxidant activity. The styrylsulfonylmethyloxadiazole 5b showed good antioxidant activity when compared with the standard ascorbic acid.

Synthesis and Antioxidant Activity of Styrylsulfonylmethyl 1,3,4-Oxadiazoles, Pyrazolyl/Isoxazolyl-1,3,4-oxadiazoles

A new class of mono and bis heterocycles-styrylsulfonylmethyl 1,3,4-oxadiazoles, pyrazolyl/isoxazolyl-1,3,4-oxadiazoles were prepared and studied their antioxidant activity. The compound methyl substituted 2-(p-methylphenylamino-sulfonylmethyl)-5-[Z-(p-methylstyrylsulfonylmethyl)]-1,3,4-oxadiazole displayed slightly higher antioxidant activity than the standard ascorbic acid.

Synthesis and Antimicrobial Activity of Azole Derivatives

A new class of mono and bis heterocycles, sulfonylmethaneamido linked oxazoles, thiazoles, imidazoles, pyrrolyl oxazoles, pyrrolyl thiazoles and pyrrolyl imidazoles were prepared adopting simple and versatile synthetic methodologies. The compound chloro substituted imidazolyl styrylsulfonylacetamide is the most potent antimicrobial agent particularly against Pseudomonas aeruginosa and Penicillium chrysogenum.

Aurophilic interactions as a subject of current research: an up-date

Recently accumulated experimental evidence for aurophilic interactions in and between molecular gold(I) compounds and the results of pertinent theoretical calculations are reviewed for the period from 2007 to mid-2011. The influence of the intra- and intermolecular bonding contacts between the closed-shell metal centres, Au-Au, on the molecular and crystal structures, and the consequences of these effects for the chemical and physical properties of gold compounds are summarized for the various classes of mono- and polynuclear systems. The literature survey builds on the contents of previous reviews and relates new experimental and theoretical findings to earlier observations (353 references).

DNA binding, DNA hydrolase and phosphatase like activity of new polyaza macrobicyclic binuclear copper(II), nickel(II) and zinc(II) complexes

A new class of mono, polyaza macrobicyclic binuclear copper(II), nickel(II) and zinc(II) complexes 1–6 are synthesized and characterized. The redox, phosphate hydrolysis, DNA binding and cleavage properties of complexes 1–6 are studied. The mononuclear Cu(II)-complex 1 is structurally characterized by single-crystal X-ray diffraction study. They exhibit a quasi-reversible cyclic voltammetric response near −0.65V versus Ag/AgCl in CH3CN-0.1M TBAP assignable to the M2II/M2I redox couple. The initial rate values for the hydrolysis of 4-nitrophenylphosphate to 4-nitrophenolate by the complexes 1–6 are in the range from 1.82×10−6 to 1.25×10−4s−1. The complexes show good binding propensity to calf thymus DNA giving binding constant values in the range from 1.1 to 9.5×105M−1. The binding site size and viscosity data suggest the DNA groove binding of the complexes. The complexes display significant hydrolytic cleavage of supercoiled pBR322 DNA at pH 7.2 and 37°C. The hydrolytic cleavage mechanism is further supported by free radical quenching and T4 ligase ligation results. The pseudo-Michaelis–Menten kinetic parameters kcat=2.13±0.3h−1 and KM=5.12×10−5M for macrobicyclic binuclear zinc(II) complex (6) were obtained.

Electrochemical, magnetic, catalytic, DNA binding and cleavage studies of new mono and binuclear copper(II) complexes

A new class of mono [CuL] ( 1) and binuclear copper(II) complexes [Cu 2LB](ClO 4) 2 ( 2 and 3), where L (6,6-piprazine-1,4 diyl-dimethylene bis(4-methyl phenol) is a N 2O 2 donor ligand and B is a N,N-donor heterocyclic base, viz. 2,2-bipyridyl (bipy) ( 2) and 1,10-phenanthroline (phen) ( 3), has been synthesized. These complexes were characterized by elemental and spectroscopic techniques. The redox, magnetic, catalytic, DNA binding and cleavage activities of the copper(II) complexes ( 1– 3) were studied. Cyclic voltammetric investigation of the mononuclear Cu(II) complex ( 1) shows a quasi-reversible one electron reduction wave ( E 1/2 = −0.87 V) and the binuclear Cu(II) complexes show two quasi-reversible one electron reduction processes around E 1 / 2 1 = - 0.28 V , −0.18 V and E 1 / 2 2 = - 0.72 V , −0.66 V versus Ag/AgCl in DMF, 0.1 M TBAP. ESR spectra of the copper(II) complexes 2 and 3 show a broad signal at g = 2.08 and 2.10, and μ eff values 1.32 and 1.35 BM respectively, which convey spin–spin interactions between the two copper(II) ions. Cryomagnetic investigation of the binuclear complexes reveals a weak antiferromagnetic spin exchange interaction between the Cu(II) ions within the complexes (−2 J = 228.3 ( 2) and 237.5 cm −1( 3)). The initial rate values for the oxidation of 3,5-di- tert-butylcatechol to o-quinone by the mono and binuclear Cu(II) complexes 1, 2 and 3 are 2.6 × 10 −7, 6.8 × 10 −5 and 2.3 × 10 −5 M s −1 respectively. The complexes 2 and 3 show good binding propensity to calf thymus DNA, giving binding constant values of 0.37(± 0.1) × 10 5 ( s = 0.1) and 0.44(± 0.2) × 10 5 M −1 ( s = 0.1) respectively. The complexes display significant oxidative cleavage of circular plasmid pBR322 DNA in the presence of mercaptoethanol using singlet oxygen as a reactive species. The phenanthroline containing binuclear Cu(II) complex 3 displays a better DNA interaction and significant chemical nuclease activity compared to the bypyridyl analog 2 and the mononuclear complex 1.

Synthesis, characterization, and OLED application of oligo( p-phenylene ethynylene)s with polyhedral oligomeric silsesquioxanes (POSS) as pendant groups

Two new classes of mono- and oligo( p-phenylene ethynylene)s grafted with polyhedral oligomeric silsesquioxanes (POSS) were synthesized via ‘click’ chemistry and palladium-catalyzed Sonogashira cross-coupling. These materials with cubic silsesquioxanes are very robust with excellent thermal stability in air ( T 5%loss>330 °C) and exhibited T g>80 °C. All the compounds showed high photoluminescence with a range of blue emission and quantum yield up to 80% in the solution. Extended π conjugation molecules of oligo- pPEs POSS maintain relatively high PL quantum efficiencies in the solid state, compared to mono- pPEs POSS. A preliminary report is made of some of the materials as multilayer OLED components with active dopants PVK and PBD.

Syntheses and characterization of a new class of mono‐ and heterodinuclear derivatives of boron derived from Schiff bases

AbstractReactions of 2‐isopropoxy‐1, 3, 2‐ benzodioxaborole with equivalent amounts of Schiff base ligands having two hydroxyl groups (1a–3a) yield mononuclear derivatives with one residual hydroxy group. The reactions of these mononuclear derivatives with hexamethyldisilazane in a 2:1 ratio yield heterodinuclear derivatives. All these newly synthesized derivatives have been characterized by elemental analyses and molecular weight measurements. Tentative structures have been proposed on the basis of IR and NMR (1H, 13C, 11B,29Si)spectral data and Fab‐mass studies. Schiff bases and their corresponding mono‐ and heterodinuclear derivatives of boron have also been screened for antifungal activities. Copyright © 2010 John Wiley & Sons, Ltd.

A Flexible Approach to Different Families of Bidentate P,P Ligands as Highly Efficient Ligands for Asymmetric Catalysis

AbstractA novel and versatile approach has led to the synthesis of various classes of mono‐ and bidentate phospholane and phosphinite ligands based on a benzothiophene scaffold. The ligand functions in the bidentate ligands can be introduced independently and consecutively. A bis‐phospolane ligand as well as its rhodium complex have been characterized by crystal‐structure determinations. The bis‐phospholane ligands were tested in the catalysed asymmetric homogeneous hydrogenation of dehydroamino acid derivatives, enamides and itaconates and gave ee values of up to 98.7 %. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

A New Class of Mono- and Tetra-nuclear Titanatranes: Synthesis, Structure, and Ethylene Polymerization Studies. Role of Single-Sited Active Species?

Mono- and tetranuclear titanatranes bearing the C3-symmetric aminotriol ligand N(CH2CHPhOH)3 were synthesized. The structure of the tetratitanium compound was determined by single-crystal X-ray crystallography. The new titanatrane derivative included four aminotriols ligated to four titanium atoms, forming a tetranuclear unit with μ2-O and μ3-O bridges. The mono- and tetranuclear titanatranes were capable of polymerizing ethylene with a turnover frequency of up to 375 kg of PE/((mol of catalyst) h bar). The polymers obtained had Tm ≈ 133 °C, indicative of linear polyethylene, and were further characterized by NMR. The ethylene polymerization activities of mono- and tetranuclear titanium catalysts were related by a factor of 4, indicating possibly the formation of a common single-site active species.