Bhavna Trivedi

Epoxidation of olefins catalysed by Mn(III)-Schiff base complexes

Abstract Mn(III) complexes of Schiff base ligands have been synthesized by the reaction of MnCl 2 ·4H 2 O in ethanolic solutions with the Schiff bases obtained by the condensation of 1,3-diaminopropane or 1,3-diamino-2-hydroxypropane with salicylaldehyde, 2-hydroxynaphthaldehyde or 2-hydroxyacetophenone. The complexes were characterized by elemental analysis, IR spectral, thermogravimetric, conductance, magnetic susceptibility and FAB mass spectral studies. These complexes have been employed as catalysts for the epoxidation of olefins using iodosylbenzene as an oxidant. The efrect of OH substitution on the Schiff base ligand in the complex on its catalytic activity towards epoxidation has been studied.

Synthesis of binuclear complexes of manganese(II), chromium(III), and iron(III) with 1,3-bis[1-(pyridin-2-yl)-ethylideneamino]propan-2-ol and study of their use as catalyst for epoxidation of alkenes

Abstract Binuclear complexes of Mn(II), Cr(III), and Fe(III) were synthesized using 1,3-bis[1-(pyridin-2-yl)ethylideneamino]propan-2-ol as a ligand. The complexes were characterized by analytical, spectral, and conductance studies. These complexes have been examined as catalysts for epoxidation of alkenes using iodosylbenzene as an oxidant. Manganese(II) complex was found to be a more effective catalyst than the corresponding chromium(III) complex. The iron(III) complex showed poor catalytic activity. A μ-oxo intermediate, probably responsible for the termination of catalytic activity in the epoxidation reaction, has been isolated.

Polyethylene Waxes: Catalytic Synthesis by Ti‐Biphenolates

Soluble complexes of Ti (IV) bearing biphenol groups such as 1,1′‐binaphthelene 2, 2′ diol (Binol), 1,1′‐methylene di‐2‐naphthol, biphenol were prepared and characterized. These catalyst precursors formulated as [Ti(O‐O)(OPr i )Cl] are found to be active in polymerization of ethylene at high temperatures in combination with ethylaluminum sesquichloride (Et3Al2Cl3) as co‐catalyst. The ultra low‐molecular weight polyethylenes are linear, crystalline and display narrow polydispersities. The PE waxes obtained with this catalytic system exhibit unique properties that have potential applications in surface coating and adhesive formulations.

Antithrombocytopenic activity of carpaine and alkaloidal extract of Carica papaya Linn. leaves in busulfan induced thrombocytopenic Wistar rats

ETHNOPHARMACOLOGICAL RELAVANCE The decoction of Carica papaya Linn. leaves is used in folklore medicine in certain parts of Malaysia and Indonesia for the treatment of different types of thrombocytopenia associated with diseases and drugs. There are several scientific studies carried out on humans and animal models to confirm the efficacy of decoction of papaya leave for the treatment of disease induced and drug induced thrombocytopenia, however very little is known about the bio-active compounds responsible for the observed activity. The aim of present study was to identify the active phytochemical component of Carica papaya Linn. leaves decoction responsible for anti-thrombocytopenic activity in busulfan-induced thrombocytopenic rats. MATERIALS AND METHODS Antithrombocytopenic activity was assessed on busulfan induced thrombocytopenic Wistar rats. The antithrombocytopenic activity of different bio-guided fractions was evaluated by monitoring blood platelet count. Bioactive compound carpaine was isolated and purified by chromatographic methods and confirmed by spectroscopic methods (LC-MS and 1D/2D-1H/13C NMR) and the structure was confirmed by single crystal X-ray diffraction. Quantification of carpaine was carried out by LC-MS/MS equipped with XTerra(®) MS C18 column and ESI-MS detector using 90:10 CH3CN:CH3COONH4 (6mM) under isocratic conditions and detected with multiple reaction monitoring (MRM) in positive ion mode. RESULTS Two different phytochemical groups were isolated from decoction of Carica papaya leaves: phenolics, and alkaloids. Out of these, only alkaloid fraction showed good biological activity. Carpaine was isolated from the alkaloid fraction and exhibited potent activity in sustaining platelet counts upto 555.50±85.17×10(9)/L with no acute toxicity. CONCLUSIONS This study scientifically validates the popular usage of decoction of Carica papaya leaves and it also proves that alkaloids particularly carpaine present in the leaves to be responsible for the antithrombocytopenic activity.

Synthesis and characterisation of mixed ligand complexes of Cu(II) containing optically active R-(+)- & S-(-)-1,1‘-bi-2-naphthol (BINOL)

The novel mixed ligand complexes of Cu(II) with optically active R-(+)- / S-(–)-1,1′-bi-2-naphthol and N, N′ – donor bidentate ligands have been synthesised and characterised by elemental analysis and various spectral studies.

Electrochemical Studies of Betti Base and Its Copper(II) Complex by Cyclic and Elimination Voltammetry

The electrochemical behavior of Betti base 1-(α-amino benzyl)-2-naphthol (BB) and its copper(II) complex by cyclic and elimination voltammetry (EVLS) is reported in the present study. The cyclic voltammetric studies carried out at a glassy carbon working electrode, Ag/Ag