Transition metal complexes of 5-bromosalicylidene-4-amino-3-mercapto-1,2,4-triazine-5-one: Synthesis, characterization, catalytic and antibacterial studies

Transition metal complexes of 5-bromosalicylidene-4-amino-3-mercapto-1,2,4-triazine-5-one with metal precursors, such as Cu(II), Ni(II), Co(II) and Pd(II), were synthesized and characterized by physico–chemical and spectroscopic techniques. All the complexes are of the ML type. Based on analytical, spectral data and magnetic moments, the Co(II) and Ni(II) complexes were assigned octahedral geometries, while the Cu (II) and Pd(II) complexes square planar. A study on the catalytic oxidation of benzyl alcohol, cyclohexanol, cinnamyl alcohol, 2-propanol and 2-methyl-1-propanol was performed with N-methylmorpholine-N-oxide (NMO) as co-oxidant. All the complexes and their parent organic moiety were screened for their biological activity on several pathogenic bacteria and were found to possess appreciable bactericidal properties

Schiff Base Complexes for Catalytic Application

Primary amines are combined with an aldehyde group to generate Schiff base compounds, which are called condensation imine products. This class of compounds has a general structure, R-C=NR\u27, where R and R\u27 represent alkyl/aryl/cyclohexyl/heterocyclic group. These compounds contain an azomethine group that is basic in nature due to, (i) the presence of lone pair of electrons on the nitrogen and (ii) electron-donating nature of the double bond. Hence, these compounds, as ligands, participate in the formation of metal complexes. The presence of lone pair of electrons on the nitrogen atom and the hybridization involved explains the physical, chemical, and spectral properties of nitrogen-containing moieties. In the case of (sp2) hybridization (trigonal structure), the lone pair of electrons occupies either a symmetrical unhybridized 2p orbital that is perpendicular to the plane of trigonal hybrids or a symmetrical hybrid orbital, whose axis is in the plane, leaving behind only the π-electrons in the unhybridized 2p orbital. A very similar type of hybridization is experienced by the nitrogen atom in the azomethine group. Traditional phosphine complexes of nickel, palladium, and platinum, particularly those of palladium, have played an extremely important role in the development of homogeneous catalysis. Schiff base complexes as catalysts have been studied for various organic transformations such as oxidation, epoxidation, reduction, coupling reactions, polymerization reactions, hydroformylations, and many more

Inhibition of mild steel corrosion by 4-[(benzylidene)-amino]-antipyrine

The inhibition effect of 4-[(benzylidene)-amino]-antipyrine (BAAP) on corrosion behaviour of mild steel in 1 M HCl solution was studied by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. Polarization measurements indicate that BAAP acts as mixed type of inhibitor. The adsorption of BAAP on the mild steel surface follows Langmuir adsorption isotherm model. The thermodynamic parameters governing the adsorption process were determined and discussed. Also, quantum chemical parameters were calculated to provide further insight into the mechanism of inhibition action of BAAP

Selective N-alkylation of amines with alcohols via hydrogen transfer catalyzed by copper complex in an ionic liquid media

A catalytic system containing a copper-Schiff base complex in ethyl methyl imidazolium hexafluoro phosphate [(EMIM)PF6] ionic liquid, where the ionic liquid was used as a solvent, was found to be very effective to catalyze the synthesis of benzazoles [i.e. imidazoles (C–N), thiazoles (C–S) and oxazoles (C–O)]. Substituted amines and alcohols reacted with each other in the given reaction conditions to give benzazoles. The reaction proceeded via a hydrogen transfer mechanism, which was proved by conducting series of reactions involving the conversion of aldehydes/ketones to corresponding primary and secondary alcohols. The reaction conditions were optimized with respect to catalyst concentration, best choice of the solvent, effect of different bases and the optimized chosen ones. It was found that the reaction required as low as 0.1 mol% of the catalyst and potassium carbonate as the base. Most interestingly the quantity of the products yielded the same when an equal ration of water: [EMIM]PF6 mixture was used as the solvent, same as when the ionic liquid alone was used as the solvent. A wide range of substituted alcohols and amines were tested and the products were formed within a short reaction time and comparatively good yields