Inhibition of corrosion of commercial mild steel in presence of tetrazole derivatives in acid medium

The inhibitive influence of tetrazole derivatives namely, 1-(9¹-acridinyl)-5-(4′-aminophenyl) tetrazole, 1-(9′-acridinyl)-5-(4′-hydroxy phenyl) tetrazole and 1-(9′-acridinyl)-5-(4′-chlorophenyl) tetrazole on the corrosion of commercial mild steel in 1 N hydrochloric acid medium was studied by weight loss method. The monolayer adsorption has been confirmed by fitting the data to the Langmuir adsorption isotherm. Weight loss studies have been carried out at 303K, 318K and 333K. Thermodynamic parameters like heat of adsorption, activation energy and free energy change have been calculated. The maximum inhibition of efficiency of tetrazole derivatives, 1-(9′-acridinyl)-5-(4′-amoinophenyl) tetrazole, 1-(9′acridinyl)-5-(4′-hydroxyphenyl) tetrazole and 1-(9′-acridinyl)-5-(4′-Chlorphenyl) tetrazole was found to be 60.59%, 89.00% and 92.74, respectively. Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003.     

Inhibition of corrosion of aluminium in presence of fluorescein in basic medium

The influence of Fluorescein in conjunction with calcium oxide on the corrosion of Aluminium in 1.0 N NaOH was studied by galvanostatic studies and weight loss studies. It has been found that the inhibition of corrosion of aluminium increased with the increasing concentration of the inhibitor. The maximum inhibition efficiency of fluorescein alone was found to be 30.80%. However, the addition of calcium oxide increased the maximum inhibition efficiency to 53.71%. The corrosion process was found to be under the anodic control, in the presence or in the absence of inhibitor. The inhibition was found to be mixed type. Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, Inida, Nov. 28–30, 2003.     

Novel Bioactive Co(II), Cu(II), Ni(II) and Zn(II) Complexes with Schiff Base Ligand Derived from Histidine and 1,3-Indandione: Synthesis,Structural Elucidation,Biological Investigation and Docking Analysis

Novel bioactive complexes of Co(II), Cu(II), Ni(II) and Zn(II) metal ions with Schiff base ligand derived from histidine and 1,3-indandione were synthesized and thoroughly characterized by various analytical and spectral techniques. The biological investigations were carried out to examine the efficiency of the binding interaction of all the complexes with calf thymus DNA (CT-DNA). The binding properties were studied and evaluated quantitatively by K_b and K_sq values using UV-visible, fluorescence spectroscopy and voltammetric techniques. The experimental results revealed that the mode of binding of all the complexes with CT-DNA is via intercalation. It is further verified by viscosity measurements and thermal denaturation experiments. From the results of the cleavage study with pUC19 DNA it is inferred that all the complexes possess excellent cleaving ability. The present investigation proved that the binding interaction of all the complexes are significantly strong and the order of binding strength of the complexes is [Ni(L)₂] (K_b = 3.11 × 10⁶ M^?1) > [Co(L)₂] (K_b = 2.89 × 10⁶ M^?1) > [Cu(L)₂] (K_b = 2.64 × 10⁶ M^?1) > [Zn(L)₂] (K_b = 2.41 × 10⁵ M^?1). The complexes were also screened for antibacterial and anticandidal activity. The in vitro cytotoxicity of the ligand and complexes on the NIH/3 T3 mouse fibroblast cell lines were examined using CellTiter-Blue® (CTB) Cell viability assay, which unveiled that all the complexes exhibit more potent activities against NIH/3 T3 cells. Among all the complexes [Zn(L)₂] complex showed the maximum efficiency.     

Anthracen-9-ylmethylene-(4-methoxyphenyl)amine: efficient promoter for silver-free palladium-catalyzed aerobic oxidative Sonogashira reactions

An efficient protocol for the synthesis of unsymmetrical substituted diarylacetylenes by the C(sp²)–C(sp) cross-coupling reactions of substituted phenylacetylenes and electronically different arylboronic acids has been developed. Anthracen-9-ylmethylene-(4-methoxyphenyl)amine was employed as an efficient promoter in this Pd(OAc)₂-catalyzed oxidative Sonogashira reaction in air in the absence of silver salt under optimized reaction conditions. The impact of reaction parameters such as solvent, base, reaction temperature and time in this silver-free aerobic oxidative Sonogashira cross-coupling reaction was also evaluated. Electron-deficient phenylacetylenes, which are sluggish coupling partners in the traditional Sonogashira reaction, underwent coupling in this protocol. The catalytic system is inexpensive, effortlessly attainable and highly flexible for functionalized phenylacetylenes and arylboronic acids.

Graphic abstract