Başak Doğru Mert

Recent developments in the chemistry of bicyclic 6-6 systems: chemistry of pyrido[4,3-d]pyrimidines

The present review provides a study on the structure features, reactions and synthetic methodologies of pyrido[4,3-d]pyrimidines. 5,6,7,8-Tetrahydropyrido[4,3-d]pyrimidine and related compounds have been used as starting materials for the multi-step synthesis of tetrahydropteroic acid derivatives. The aim of this review is to give an overview of the diverse methodologies that have been reported on the chemistry of pyrido[4,3-d]pyrimidines. The different synthetic routes have been grouped according to the way the pyrido[4,3-d]pyrimidine moiety has been created. Thus, the investigated compounds were obtained from pyridine and pyrimidine derivatives or from multicomponent synthesis. The mechanistic pathways of the reactions and the important biological applications are discussed.

Advances in 1,3,5-triazepines chemistry

This review describes a literature survey of 1,3,5-triazepines. The investigated heterocycles were the monocyclic and fused 1,3,5-triazepines. The different sections of the paper cover: theoretical methods, spectroscopy aspects, thermodynamic aspects, synthesis and reactions of the monocyclic and fused heterocycles incorporated into the 1,3,5-triazepine moiety. The biological evaluation of the target compounds are also described as well as their synthetic applications. The reaction mechanisms are discussed.

The experimental and quantum chemical investigation for two isomeric compounds as aminopyrazine and 2-amino-pyrimidine against mild steel corrosion

Purpose The purpose of this paper is to investigate the adsorption and corrosion inhibition of two isomeric compounds (C4H5N3) as aminopyrazine (AP) and 2-amino-pyrimidine (2AP) on mild steel (MS) in 0.5 M HCl. The study was a trial to combine experimental and modelling studies and research effect of molecular geometry on inhibition effect of inhibitor molecules. Design/methodology/approach The thermodynamic, kinetic and quantum parameters were determined. The electrochemical impedance spectroscopy and anodic polarisation measurements were obtained. The scanning electron microscope was used for monitoring electrode surface. The highest occupied molecular orbital, energy of the lowest unoccupied molecular orbital, Mulliken and natural bonding orbital charges on the backbone atoms, absolute electronegativity, absolute hardness were calculated by density functional theory (DFT)/B3LYP/6-311G (++ d,p). Findings Results showed that AP and 2AP suppressed the corrosion rate of MS. The corrosion current values were 0.530, 0.050 and 0.016 mA cm-2 in HCl, AP and 2AP containing HCl solutions, respectively. It was illustrated with the blocked fraction of the MS surface by adsorption of inhibitors which obeyed the Langmuir isotherm. The inhibition efficiency follows the order: 2AP > AP which is in agreement with experimental and quantum results. Originality/value This paper provides lay a bridge on the molecular geometry and inhibition efficiency by electrochemical tests and modelling study. The inhibition effect of AP and 2AP has not been compared with each other, neither experimentally nor theoretically. This study put forward possible application of 2AP as corrosion inhibitor especially for closed-circuit systems.

Enhanced corrosion resistance and surface characterization of anodized 7075 Al

In this study, we aim to enhance physical and chemical properties of 7075 aluminum via anodizing. For this purpose, convenient potential, current density, time, electrolyte type and its concentration were determined. The corrosion performances of non-anodized and anodized samples have been investigated in 3.5% NaCl by using EIS, polarization techniques. The surface morphology was determined with SEM. As a result, additive (0.5 M C2H6O2 + 0.08 M H3BO4 + 10–3 Al+3) used in 0.4 M H2SO4 was improved the quality of aluminium oxide by blocking pores, increasing the thickness and decreasing the oxide formation potential. It was achieved corrosion resistance.