@article { ISI:000367546300012, title = {Synthesis, crystal structure and in vitro DNA binding studies of combretastatin A-4 analogue}, journal = {Croatica Chemica Acta}, volume = {88}, number = {3}, year = {2015}, month = {DEC}, pages = {289-296}, publisher = {CROATIAN CHEMICAL SOC}, address = {MARULICEV TRG 19/II, 41001 ZAGREB, CROATIA}, abstract = {

Synthesis of a novel Combretastatin A-4 analogue using Schiff{\textquoteright}s reaction of benzil and 4-aminoantipyrine has been achieved under solvent free conditions. The structure of compound was examined spectroscopically and confirmed from single crystal diffraction studies. The synthesized Combretastatin A-4 analogue was investigated for its DNA binding ability as the plausible mechanism for its antitumor activity. The binding propensity of the synthesized compound with calf-thymus (CT) DNA was monitored with absorption and emission spectrophotometric titrations. The calculations predict a binding constant of 7.24 x 10(4) for the complex of the synthesized compound with CT DNA which is comparable in magnitude to that of DNA binding of bactericidal drug enoxacin and typical intercalation indicator ethidium bromide (EB). Competitive binding studies of the synthesized compound with EB using fluorescence titration reveal that it displaces the DNA-bound EB and binds in intercalative mode which was further supported by circular dichroism (CD) spectroscopy. The probable site and binding energy of the compound with DNA was further theoretically investigated by molecular docking studies. The significant DNA binding ability of the synthesized Combretastatin A4 analogue as revealed from this study could be related to the anticancer activity of the Combretastatin A4.

}, keywords = {benzil, bio-physical, combretastatin A-4, crystal structure, DNA binding, ethidium bromide, fluorescence, phenazones}, issn = {0011-1643}, doi = {10.5562/cca2662}, author = {Rizvi, Masood Ahmad and Dangat, Yuvraj B. and Yaseen, Zahid and Gupta, Vivek and Khan, Khaliquz Zaman} } @article { ISI:000370464800023, title = {Complexation key to a pH locked redox reaction}, journal = {Journal of Chemical Education}, volume = {93}, number = {2}, year = {2016}, month = {FEB}, pages = {355-361}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

An unfavorable pH can block a feasible electron transfer for a pH dependent redox reaction. In this experiment, a series of potentiometric titrations demonstrate the sequential loss in feasibility of iron(II) dichromate redox reaction over a pH range of 0-4. The pH at which this reaction failed to occur was termed as a pH locked reaction. The comparative ability of 10 selected iron binding ligands with varied propensity for the redox potential modification of Fe(III)/Fe(II) redox couple to restore/unlock the pH locked redox reaction is shown using potentiometric titrations. The spectrophotometric speciation analysis of Fe(III) Tiron complexation with pH was carried out to explain the differing ability of EDTA and Tiron to unlock the reaction under different pH Conditions. The experiment illustrates how environmental, biological redox reactions avoid severe laboratory conditions to occur and can be explored in the design of novel redox systems for natural attenuation of environmental toxins to their non- or lesser-toxic forms. The experiment also demonstrates prudent laboratory practice for safe waste disposal.

}, keywords = {Analytical Chemistry, Aqueous Solution Chemistry, Coordination Compounds, Oxidation/Reduction, pH, Physical Chemistry, Potentiometry, Second-Year Undergraduate, Thermodynamics, Titration/Volumetric Analysis, Upper-Division Undergraduate}, issn = {0021-9584}, doi = {10.1021/acs.jchemed.5b00499}, author = {Rizvi, Masood Ahmad and Dangat, Yuvraj B. and Shams, Tahir and Khan, Khaliquz Zaman} } @article { ISI:000366590300006, title = {Exploring activity differences between the hydroformylation catalysts: Insights from theory}, journal = {Journal of Organometallic Chemistry}, volume = {801}, year = {2016}, month = {JAN}, pages = {30-41}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Hydroformylation catalysis is the most important homogeneous catalysis process of the current day. The current computational investigation aims to understand the nature of the hydroformylation process when monodentate ligands are employed. The complete catalytic cycle for different monodentate ligands bound to the rhodium center has been studied with full quantum chemical calculations, with density functional theory (DFT). To the best of our knowledge, this is the first systematic investigation of the relative free energy surfaces for mono-coordinate monodentate and bi-coordinated monodentate ligands in hydroformylation catalysis. The results indicate that the barriers are lower for the mono-coordinate monodentate species in comparison to the bi-coordinate monodentate, for all the ligand cases studied, indicating higher activity for the mono-coordinate monodentate active species. (C) 2015 Elsevier B.V. All rights reserved.

}, keywords = {Density functional theory (DFT) calculations, Hydroformylation, Monodentate, Rhodium}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2015.10.015}, author = {Dangat, Yuvraj B. and Rizvi, Masood Ahmad and Pandey, Pippalad and Vanka, Kumar} } @article {45730, title = {Computational survey of ligand properties on iron(III)-iron(II) redox potential: exploring natural attenuation of nitroaromatic compounds}, journal = {Monatshefte Fur Chemie}, volume = {148}, year = {2017}, month = {APR}, pages = {655-668}, type = {Article}, abstract = {

This study is a computational investigation of the ligand effect on the redox potential of iron redox couple aimed at screening these systems for novel applications. The influence of common and naturally available organic compounds with diverse ligand characteristics (nature of donor site, chelation, pre-organization, degree of back acceptance) on the redox potential of iron(III)-iron(II) redox couple has been theoretically calculated using an appropriate level of density functional theory (DFT). The DFT calculated redox potentials of iron complexes are explored to supplement, corroborate, and predict the experimental behavior of the studied systems towards environmental reduction of nitroaromatic compounds to corresponding anilines. The comparative avidity of iron complexes with cysteine derivatives for the reduction of nitroaromatic compounds has been theoretically explored and based on structure-activity relationship; new iron complexes with a range of reactivity and enhanced ability towards nitroaromatic reduction have been predicted.

}, keywords = {Catechol derivatives, computational chemistry, Density functional theory, Iron complexes, Ligand effect on redox potential, Natural attenuation, Nitroaromatic compounds}, issn = {0026-9247}, doi = {10.1007/s00706-016-1813-8}, author = {Rizvi, Masood Ahmad and Mane, Manoj and Khuroo, Mohammad Akbar and Peerzada, Ghulam Mustafa} }