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Stability of Binary Complexes of 1, 10-Phenanthroline
in Propylene Glycol-Water Mixtures
-- B Rama Raju, K V Santhee Devi and G Nageswara Rao
The complex formation equilibria involved in binary systems of M(II)-Phen were investigated pH metrically at 303 K and an ionic strength of 0.16 mol L–1 (M = Cobalt (Co), Nickel (Ni) and Copper (Cu); Phen (1, 10-Phenanthroline)). The existence of ML, ML2, ML3 and their stability constants are refined with the computer program MINIQUAD75. The best fit chemical models were selected based on the statistical parameters like crystallographic R-factor and sum of squares of residuals in massbalance equations. The formation and distribution of different species with relative concentrations (M:L = 1:2.5, 1:3.75 and 1:5.0) of metal and ligand with varying pH were represented in the form of distribution diagrams. The influence of cosolvent on speciation was discussed based on the dielectric constant of the medium. © 2011 IUP. All Rights Reserved.
Thermal Decomposition of Ammonium Dioxoperoxymalonato
Uranate (VI) Tetra Hydrate
-- B B V Sailaja and M S Prasada Rao
Ammonium dioxoperoxymalonato Uranate (VI) tetrahydrate was obtained by reaction
of Uranyl nitrate (U O2(N O3)2) with Malonic acid (CH2(COOH)2), and then Hydrogen
peroxide (H2O2) in the presence of Ammonium ion (NH4 +). The complex was subjected
to chemical analysis. The chemical analysis of the complex was performed by using
elemental analyzer and thermogravimetric techniques such as Thermogravimetric
Analysis (TGA), Differential Thermal Analysis (DTA) and Differential
Thermogravimetric Analysis (DTG). The complex and the intermediate products of
its thermal decomposition were further characterized by using Infrared (IR) absorption
and X-ray diffraction spectra. Based on the data from these physico-chemical
investigations, the structural formula of the complex was proposed as
(NH4)2[UO2(O2)(H2C3O4)].4H2O.
© 2011 IUP. All Rights Reserved.
Influence of Polythiophene-Anthraquinone Sulphonic Acid
on the Corrosion Inhibition of Mild Steel in 1N HCl Medium
-- G Thirunarayanan, K Thirumurthy and A Subramania
Polythiophene-Anthraquinone Sulphonic Acid (PTh-AQSA) was prepared by dilute polymerization method. This polymer was characterized by Fourier Transform InfraRed (FTIR) spectra and Scanning Electron Microscope (SEM) analysis. Different corrosion parameters such as corrosion rate, surface coverage (°) and inhibition efficiency for different concentrations of inhibitors are studied. The absorption of this polymer on a metal surface was found to be obeying Langmuir adsorption isotherm. The polymer controlled both anodic and cathodic reactions by blocking the active sites of steel surface and thus the inhibitor was of mixed type. Impedance measurements revealed that a decrease in the Cdl may be due to the adsorption of PTh-AQSA to form an adherent film on the metal surface. © 2011 IUP. All Rights Reserved.
Quantum Chemical Study of Halomon
by the DFT and MP2 Methods
-- Bhaskar Bagchi and Asim Kumar Bothra
The molecular geometry of Halomon in the ground state has been calculated by B3LYP/ 6-31G(d, p) and MP2/6-31G(d, p) methods. An examination of its structure suggests that rotation around a single bond between C3-C9 and C6-C7 is not quite free due to steric factor. The Br atom present at C9 and the bulky group –(CH2)2-CHBr-CCl(CH3)2 present at C3 are oppositely directed (anti). The Cl atom attached to C7 and the –CH2- CH2- group present at C6 are gauch to each other. For the optimized structure, the standard thermodynamic functions have been calculated, and the harmonic vibrational frequencies for Halomon are calculated at the B3LYP/6-31G(d, p). © 2011 IUP. All Rights Reserved.
Isomerism, the Chemistry of Iron Heterometallic Compounds: Part IV
Heteropenta- to Heterooligomeric Clusters -- Milan Melnik and Ondrej Sprusansky
The iron heteropenta- and heterooligometallic iron clusters cover huge fields, as shown
by a survey covering the crystallographic and structural data of over 470 examples.
About 5% of those clusters exist as distortion isomers and are summarized. Those are
discussed in terms of coordination around the metal atoms, bond length and bond
angles. The isomers are crystallized in triclinic, monoclinic, orthorhombic and
tetragonal systems, of which triclinic and monoclinic are the most common. The
isomers were found in the series of pentameric (x5) hexameric (x9), heptameric (x5)
and octameric (x4) clusters. There are 16 different metal parameters with the iron (Fe)
atom, non-transition (Li, Ge, Sn, Sb, Tl, Cd, Hg and Te) and transition (Mo, Ru, Rh,
Os, Ir, Pt, Co and Au). The shortest metal-metal bond distances are—2.621(1) (Fe–
Fe); 2.347(2) (Fe–Ge); 2.533(4) (Fe–Au); 2.334(5) (Ge–Co) and 2.434(50 (Co–Co).
© 2011 IUP. All Rights Reserved.
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