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A brief overview of mechanistic studies of the reactions of Pd(II)-bipy-malonate complex with different set of ligands, viz., (N, S), (S, O) and (S) donor molecules is reported here. The kinetics of complex-formation reactions of three sulphur containing bio-relevant ligands thioglycolic acid[L1],thiourea[L2] and thiosemicarbazide [L3] were studied with innermetallic [Pd(bipy)(malonate)] complex at physiological condition. The effect of the nucleophilicity of the chosen nucleophiles was studied for the reactant complex under pseudo-first order conditions as a function of nucleophile concentration and temperature using stopped-flow technique. This article describes the results obtained for substitution reactions of bi-functional Pd(II) complex with different biomolecules, under varying experimental conditions. The kinetic studies showed that the malonate ring departs from the coordination zone of palladium centre via two-step mechanism. The first step depends on the concentration of the incoming ligand for all the ligands. But in the second step thiourea is ligand dependent where as other two are independent of the ligand concentration. Hence, it can be concluded that the second step is the chelation step for L1 and L3. The mechanism for the substitution of the coordinated malonate molecule is associative, as demonstrated by the negative values of ΔS ≠. Such type of complexes are less toxic than chloro-, which in turn hydrolyses to aqua or aqua complexes as they are prevented from oligomer formation at physiological pH.

Antibiotic resistance has led to the search for more effective antimicrobial agents among plant materials that can serve as source and template for the synthesis of new antimicrobial drugs. The current study aims to analyses the oil, extracted from the leaves of Crotalaria pallida for its physicochemical and antimicrobial properties. Leaf oil was extracted by petroleum ether (40–60 °C) and its fatty acid constituents were isolated as a mixture after saponification. Mixture of fatty acid was purified by TLC and characterized by IR, GC and GC–MS analysis by converting them into their FAME. MIC of the oil against the Gram positive and Gram negative bacteria was determined by agar diffusion method. Nineteen fatty acids were identified by gas-liquid chromatography followed by GC–MS. It was found that unsaturated fatty acids were present in greater amounts than saturated fatty acids. Most predominating unsaturated and saturated fatty acids were linolenic acid (34.06 ± 0.23%) and palmitic acid (24.47 ± 0.22%) respectively. The acid value (19.63 ± 0.22) and saponification value (109.08 ± 2.87) were also estimated to evaluate the quality of the oil. The oil showed good antimicrobial activities against Gram-positive bacteria, Bacillus subtilis as well as Gram-negative bacteria, Escherichia coli and Acinetobacter junii.

A new reagent has been introduced for the detection of amino acids. This reagent is capable for easy identification of amino acids on thin-layer chromatography plates by developing various distinguishable colors (detection limit: 0.08-5 µg). The colors thus obtained are more or less stable up to 6 -10 hrs.

The present communication is a first-time report on the analyses of n-alkane profile of epicuticular wax extracted from the mature leaves of Nyctanthes arbor-tristis L. during a calender year. The composition of n-alkanes revealed hentriacontane (n-C31), tritriacontane (n-C33), tetratriacontane (n-C35) and nonacosane (n-C29) as the major constituents with tritriacontane (n-C33) being the dominant constituent. The cumulative percentage of these four odd-numbered alkanes also showed phenological variation being highest during the fruit ripening stage (average value 63.29%) followed by the flowering stage (mean value 60.74%). The values remained moderate on an average of 54.31% for the rest of the year. This study also confirms the xerophytic feature of the plant having higher proportion of longer carbon chain n-alkanes greater than C31 (dominant peaks are of C33 and C35).