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8-Hydroxyquninoline Mannich base namely 7-diethylaminobenzyl-8-hydroxyqunioline(DEBQ) was synthesized and characterized by elemental analysis and spectral studies. Chelates of DEBQ with manganese(II) and nickel(II) were isolated and structurally  characterized by elemental analysis, electrical conductance, magnetic susceptibility measurement, thermal analysis, IR,UV-Vis, EPR and Mass spectral data. The Mannich base ligand is bidentate and chelates through the phenolic oxygen and the aliphatic tertiary amino nitrogen atoms. Based on the magnetic and electronic spectral data all the MnII complexes are assigned an octahedral geometry and NiII complexes are assigned a tetrahedral geometry. Antimicrobial susceptibility screening of the Mannich base shows that it possesses excellent activity when compared to the standard drugs and the metal complexes studied. Among the chelates, MnII chelate is more potent than NiII  chelate. Thermal analysis of a few compounds shows two stage decomposition patterns.

The corrosion inhibition effect of dipropyl sulphide (DPS) on carbon steel immersed in 0.5 N sulphuric acid has been evaluated at room temperature using mass loss method. The corrosion rate and inhibition efficiency was obtained from weight loss method. The corrosion inhibition efficiency increases with increase in concentration of an inhibitor. The corrosion rate decreases when increase in concentration of inhibitor. This is due to the higher concentration of inhibitor solution, which blocks the active site of a carbon steel and a protective film is formed on the carbon steel surface. Electrochemical studies have been used to confirm the formation of protective film over the carbon steel surface. This is further confirmed by surface analysis technique like FTIR spectroscopy and scanning electron microscopy. Energy dispersive analysis of X-ray was used to analyze the elements present over the carbon steel surface. Surface analysis of polished, corroded and inhibitor carbon steel surface has been evaluated by SEM. In order to study adsorption of dipropyl sulphide on carbon steel, in situ atomic force microscopy (AFM) measurements were performed in control, with and without dipropyl sulphide in 0.5 N H2SO4 solution.