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101.
Kinetic investigations on interaction of carbon monoxide with RuIICl2(PPh3)3 in mixed aqueous medium
Vivek K. Srivastava Ram S. Shukla Sharad D. Bhatt Raksh V. Jasra 《Reaction Kinetics and Catalysis Letters》2004,81(1):99-105
Kinetics, equilibrium and thermodynamics of interaction of CO with RuCl2(PPh3)3 (1) have been investigated in 1:1(v/v) water — 1,4-dioxan mixture in which 1 dissociates to RuCl2(PPh3)2 (1a), by losing a coordinated PPh3. The kinetics of complexation of (1a) with CO to form RuCl2(CO)(PPh3)2 (2) indicated first order dependence in [1a] and [CO]. The thermodynamic parameters for the formation of 2 were determined.This revised version was published online in December 2005 with corrections to the Cover Date. 相似文献
102.
Variable‐Temperature Powder X‐ray Diffraction of Aromatic Carboxylic Acid and Carboxamide Cocrystals
L. Sreenivas Reddy Prashant M. Bhatt Rahul Banerjee Ashwini Nangia Prof. Dr. Gert J. Kruger Prof. Dr. 《化学:亚洲杂志》2007,2(4):505-513
The effect of temperature on the cocrystallization of benzoic acid (BA), pentafluorobenzoic acid (FBA), benzamide (BAm), and pentafluorobenzamide (FBAm) is examined in the solid state. BA and FBA formed a 1:1 complex 1 at ambient temperature by grinding with a mortar and pestle. Grinding FBA and BAm together resulted in partial conversion into the 1:1 adduct 2 at 28 °C and complete transformation into the product cocrystal at 78 °C. Further heating (80–100 °C) and then cooling to room temperature gave a different powder pattern from that of 2 . BAm and FBAm hardly reacted at ambient temperature, but they afforded the 1:1 cocrystal 3 by melt cocrystallization at 110–115 °C. Both BA+FBAm ( 4 ) and BA+BAm ( 5 ) reacted to give new crystalline phases upon heating, but the structures of these products could not be determined owing to a lack of diffraction‐quality single crystals. The stronger COOH and CONH2 hydrogen‐bonding groups of FBA and FBAm yielded the equimolar cocrystal 6 at room temperature, and heating of these solids to 90–100 °C gave a new crystalline phase. The X‐ray crystal structures of 1 , 2 , 3 , and 6 are sustained by the acid–acid/amide–amide homosynthons or acid–amide heterosynthon, with additional stabilization from phenyl–perfluorophenyl stacking in 1 and 3 . The temperature required for complete transformation into the cocrystal was monitored by in situ variable‐temperature powder X‐ray diffraction (VT‐PXRD), and formation of the cocrystal was confirmed by matching the experimental peak profile with the simulated diffraction pattern. The reactivity of H‐bonding groups and the temperature for cocrystallization are in good agreement with the donor and acceptor strengths of the COOH and CONH2 groups. It was necessary to determine the exact temperature range for quantitative cocrystallization in each case because excessive heating caused undesirable phase transitions. 相似文献
103.
104.
[structure: see text] The synthesis of the A,B,C-ring system (2) of hexacyclinic acid (1) is achieved starting from a selective Diels-Alder reaction followed by vinyl cuprate addition. The diastereoselective reduction of the ketone carbonyl at C16 could be achieved with LiAlH(4). An intramolecular Michael addition established the ring system stereoselectively, providing access to the selective generation of 9 out of the 14 stereocenters of hexacyclinic acid. 相似文献
105.
Optimized molecular structure-antioxidant efficacy relationship of trimethylgermanium(IV) complexes involving biologically active bulky heterocyclic-O-donor ligands was investigated using density functional theory (DFT). The complexes where R = -CH2CH3[L(1)H],-C6H5[L(2)H], p-ClC6H4-[L(3)H] were prepared by the reaction of trimethylgermanium chloride with sodium salts of bulky heterocyclic-O-donor ligands in 1:1 M ratio in refluxing dry THF. The complexes were characterized by various spectroscopic techniques namely FTIR, 1H and 13C NMR. The spectral evidences are indicative of a bidentate behaviour of the ligands in these complexes which adopt a pentacoordinated geometry. Computational studies of these complexes have been carried out using B3LYP/6-31G* basis set to obtain molecular geometry, ground state energy and other global reactivity parameters. The most stable geometry having lowest optimized energy was chosen and bond lengths and bond angles were computed. The HOMO-LUMO energies for the complexes have been computed in order to ascertain the energy distribution and reactivity behaviour. These complexes were evaluated for antioxidant activity using FRAP (ferric reducing antioxidant power) assay and demonstrated potential antioxidant activity of distinguishable magnitude. 相似文献
106.
107.
Summary A thin-layer Chromatographic investigation was carried out on Silica Gel-G plates for metal dithizonates and the technique was applied for detecting metals present in autopsy tissues in cases of suspected suicide and homicide. Rf values of the common metal complexes in four Chromatographic solvents and the colour of their respective spots on the TLC plate are reported.
Zusammenfassung Die Dünnschichtchromatographie von Metalldithizonaten auf Silicagel G-Platten wurde mit dem Ziel untersucht, Metalle in Leichenteilen nach Selbstmord oder Mord nachweisen zu können. Die Rf-Werte der Dithizonate üblicher Metalle in vier zur Chromatographie verwendeten Lösungsmitteln und die Farbe der Chromatogrammflecken wurden angegeben.相似文献
108.
Prashant N. Bhatt Yadvendra K. Agrawal 《International journal of environmental analytical chemistry》2013,93(4):411-415
Abstract Fluoride gives a very stable complex with scandium and, hence, by determining the unreacted scandium, the fluoride content can be calculated. Excess scandium is reacted with an ethanolic solution of N-benzoylphenylhydroxylamine (BPHA) at pH 6.0, and the scandium-BPHA complex is extracted into isoamyl alcohol. Scandium is determined spectrophotometrically after adding xylenol orange. Beer's law for fluoride is obeyed in the range of 0.05 –1.5 ppm; the molar absorptivity is 1.94×104 1 mol?1 at 565 nm. The procedure is applicable for the determination of fluoride in various types of samples. 相似文献
109.