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Tarasevych A.,Institute of Bioorganic Chemistry and Petrochemistry | Shevchenko I.,Institute of Bioorganic Chemistry and Petrochemistry | Rozhenko A.B.,Institute of Organic Chemistry | Rozhenko A.B.,Bielefeld University | Roschenthaler G.-V.,Jacobs University Bremen
European Journal of Inorganic Chemistry | Year: 2010

The reaction of 1,8-dilithionaphthalene (1) with methylenebis[(dialkylamino)chlorophosphanes] [R2N(Cl)PCH 2P(Cl)NR2; R = Me (2a), Et (2b)] leads to the formation of new heterocyclic compounds, 1,3-diphospha-2,3-dihydro-1H-phenalenes 3a,b as a mixture of cis and trans isomers. DFT calculations indicate that the cis isomers are thermodynamically more stable by about 1-3 kcal/mol than the trans isomers. Compounds 3a, b can be converted into dithio the derivatives 5a, b and the borane complexes 6a, b which were characterized by NMR spectroscopy and investigated by X-ray diffraction analysis. The dialkylamino groups in 3 can be substituted by chlorine to give the chlorophosphane 7. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA,.

Adetola O.,East Tennessee State University | Golovko L.,Institute of Bioorganic Chemistry and Petrochemistry | Vasiliev A.,East Tennessee State University
Key Engineering Materials | Year: 2016

Silica gels containing incorporated heteropolyacids (HPAs) were synthesized in acidic media by co-condensation of tetraethoxysilane (TEOS) with phosphotungstic or phosphomolybdic acids using the sol-gel technique. The effect of the synthesis conditions on their structure and morphology was studied. Yields of modified materials were somewhat lower compared to non-modified silica gels. All materials were mesoporous but contained micropores in their structures. Presence of bands of Keggin's structures in FT-IR spectra along with absence of XRD patterns of crystalline HPAs confirmed their fine incorporation into silica network. Particle sizes of modified materials were 500-1100 nm except for the W-containing sample obtained with trimethylstearylammonium chloride, which was significantly lower. This unusual effect was attributed to stabilization of primary silica nanoparticles by interactions between the surfactant and HPA. High ratio HPA/TEOS resulted in partial loss of porosity. Obtained results might be used for optimization of synthesis of effective catalysts and adsorbents containing HPAs in mesoporous structure. © 2016 Trans Tech Publications, Switzerland.

Hamza A.,University of Kentucky | Wagner J.M.,University of Kentucky | Evans T.J.,University of Kentucky | Frasinyuk M.S.,University of Kentucky | And 5 more authors.
Journal of Chemical Information and Modeling | Year: 2014

The rise of drug-resistant Mycobacterium tuberculosis lends urgency to the need for new drugs for the treatment of tuberculosis (TB). The identification of a serine protease, mycosin protease-1 (MycP1), as the crucial agent in hydrolyzing the virulence factor, ESX-secretion-associated protein B (EspB), potentially opens the door to new tuberculosis treatment options. Using the crystal structure of mycobacterial MycP1 in the apo form, we performed an iterative ligand- and structure-based virtual screening (VS) strategy to identify novel, nonpeptide, small-molecule inhibitors against MycP1 protease. Screening of ∼485-000 ligands from databases at the Genomics Research Institute (GRI) at the University of Cincinnati and the National Cancer Institute (NCI) using our VS approach, which integrated a pharmacophore model and consensus molecular shape patterns of active ligands (4D fingerprints), identified 81 putative inhibitors, and in vitro testing subsequently confirmed two of them as active inhibitors. Thereafter, the lead structures of each VS round were used to generate a new 4D fingerprint that enabled virtual rescreening of the chemical libraries. Finally, the iterative process identified a number of diverse scaffolds as lead compounds that were tested and found to have micromolar IC50 values against the MycP 1 target. This study validated the efficiency of the SABRE 4D fingerprints as a means of identifying novel lead compounds in each screening round of the databases. Together, these results underscored the value of using a combination of in silico iterative ligand- and structure-based virtual screening of chemical libraries with experimental validation for the identification of promising structural scaffolds, such as the MycP1 inhibitors. © 2014 American Chemical Society.

Kislyuk V.V.,Taras Shevchenko National University | Kislyuk V.V.,Institute of Semiconductor Physics of Ukraine | Fedorchenko M.I.,Taras Shevchenko National University | Smertenko P.S.,Institute of Semiconductor Physics of Ukraine | And 2 more authors.
Journal of Physics D: Applied Physics | Year: 2010

The behaviour of a hybrid heterojunction (HJ) of an inorganic semiconductor cadmium sulfide (CdS) single crystal (102 Ω cm) and an organic conducting polymer poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonic acid) (PEDOT : PSS) has been studied using electrical and photoelectrical measurements as well as ultraviolet photoelectron spectroscopy (UPS) with in situ Ar ion etching. Photovoltaic data and current-voltage characteristics demonstrated that the HJ is a Schottky diode with an electron barrier height ca φb = 0.5 eV. The estimates based on the energy balance at the interface allowed us to assert on the presence of an interfacial dipole with an energy offset of -0.3 eV. A dipole barrier of the same magnitude was also clearly revealed from the UPS measurements directly. © 2010 IOP Publishing Ltd.

Shevchuk M.V.,Taras Shevchenko National University | Romanenko V.D.,Institute of Bioorganic Chemistry and Petrochemistry | Kukhar V.P.,Institute of Bioorganic Chemistry and Petrochemistry
Phosphorus, Sulfur and Silicon and the Related Elements | Year: 2011

Tetrakis(trimethylsilyl) ethenylidenebisphosphonate is proposed as a substrate in the preparations of N-substituted 2-aminoethylidene-1,1- bisphosphonic acids. The method provides an extremely mild protocol for the synthesis of these compounds and is compatible with a wide range of functional groups. Copyright © Taylor & Francis Group, LLC.

Kovalishyn V.,Institute of Bioorganic Chemistry and Petrochemistry | Poda G.,Ontario Cancer Institute | Poda G.,University of Toronto
Chemometrics and Intelligent Laboratory Systems | Year: 2015

Here we report a novel, fast and efficient algorithm for variable selection, the batch pruning algorithm (BPA). The method combines the artificial neural networks (ANN) ensemble learning and self-organized map (SOM) of Kohonen for clustering of descriptors, followed up with a selection of an optimal smaller subset of descriptors from each cluster based on calculated sensitivity of input neurons. BPA was validated on two publicly available, structurally diverse datasets: 584 inhibitors of M. Tuberculosis (MTB) growth and 1015 phosphodiesterase type 4 (PDE4) inhibitors. BPA was able to identify a smaller subset of 5% of molecular descriptors (out of about 1200 calculated with Talete Dragon) 50-100 times faster compared to conventional stepwise pruning methods (SPM), and yielded QSAR models of similar or slightly better accuracy as measured by Q2 (0.73-0.77), RMSE (0.50-0.72) and MAE (0.36-0.57). 97% of compounds were predicted within 1 log unit. It took only 1.47h to find the best set of descriptors by BPA compared to 119h by ANN SPM for the MTB dataset, and 3.0h compared to 237h for the PDE4 set. Due to its high predictive accuracy and speed, BPA may find wide applicability in building better machine learning models to predict activity, selectivity, physical and ADMET properties for large datasets, and a large number of descriptors within reasonable time. © 2015 Elsevier B.V.

Dimitriev O.P.,Institute of Semiconductor Physics of Ukraine | Pud A.A.,Institute of Bioorganic Chemistry and Petrochemistry
Synthetic Metals | Year: 2011

Interaction of emeraldine base (EB) of polyaniline (PANI) with tetraalkylammonium hydroxides (TAAHs) has been studied in N-methylpyrrolidinone solutions and complex films. The spectral changes in the solutions at the early stage of the interaction showed features typical of the increased intramolecular conductivity in PANI backbone, which has been assigned to a "pseudo" doping effect upon interaction of EB with TAAHs. Conductivity of films was found to also increase, however, intrinsic electronic conductivity of the films was completely masked by the ionic one. The above effect has been compared with that of the conventional inorganic base KOH in the same medium. It has been found that similar changes in electronic absorption spectra of EB take place within some range of concentrations of KOH in the mixture. The conclusion on strong interaction of EB and the above bases was supported by IR spectra of the complex films, which evidenced in favor of the chemical transformation of the polymer backbone. The final product was found to be unstable and degrades readily. Based on the above results the interaction of PANI and the bases used is discussed. A scheme of the possible PANI transformations is suggested. © 2011 Elsevier B.V. All rights reserved.

Smertenko P.S.,Institute of Semiconductor Physics of Ukraine | Grynko D.A.,Institute of Semiconductor Physics of Ukraine | Osipyonok N.M.,Institute of Semiconductor Physics of Ukraine | Dimitriev O.P.,Institute of Semiconductor Physics of Ukraine | Pud A.A.,Institute of Bioorganic Chemistry and Petrochemistry
Physica Status Solidi (A) Applications and Materials Science | Year: 2013

A conductive pyrolytic carbon fiber (CF) has been found to serve as an alternative material to metal electrodes, since it forms an Ohmic contact to CdS crystals. The methods of preparation of polycrystalline layers and nanocrystalline arrays of CdS are described that allow formation of an ohmic or quasi-ohmic contact to CF. It is shown that the ohmic contact between the CF and polycrystalline CdS layer is stable for at least several months and its exploitation characteristics are not worse than the indium contact. Advantages of the CF electrode, such as thermostability to extremely high temperatures and low cost are discussed. CdS nanowire arrays grown on a carbon fiber. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Turcheniuk K.V.,Institute of Bioorganic Chemistry and Petrochemistry | Shevchenko I.V.,Institute of Bioorganic Chemistry and Petrochemistry
Phosphorus, Sulfur and Silicon and the Related Elements | Year: 2011

Carbanion 4 generated from phosphane azide 3 undergoes intramolecular cyclization to give 1,2,3,4-triazaphosphole 5, which rearranges into 1,2,4-diazaphosphole 8. Copyright © Taylor & Francis Group, LLC.

Poliakov D.,Institute of Bioorganic Chemistry and Petrochemistry | Shevchenko I.,Institute of Bioorganic Chemistry and Petrochemistry
European Journal of Organic Chemistry | Year: 2010

Bis(diisopropylamino)carbene can display not only carbenelike reactivity but also enter 1, 3-addition reactions with the participation of the carbon and nitrogen atoms of the N-C-N unit. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

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