Fatma Kandemirli

Inhibition Effects of Amides on the Corrosion of Copper in 1.0 M HCl: Theoretical and Experimental Studies

Abstract The corrosion inhibition effects of benzamide (BA) and 4-aminobenzenesulfonamide (ABSA) for copper in 1.0 M hydrochloric acid (HCl) solution were investigated using potentiodynamic polarization, cyclic voltammetry (CV), and potentiostatic current-time curves. The Langmuir adsorption isotherms of the inhibitors were used to explain the adsorption behavior. In addition, surface analysis of copper was investigated using scanning electron microscopy (SEM). The results showed that the inhibition efficiency of ABSA was much better than those of BA. The theoretical study on the corrosion inhibition efficiencies for neutral and protonated forms of the BA and ABSA molecules were performed using density functional theory (DFT) and MP2 method in gas and water phases.

Experimental and Theoretical Studies on the Functionalization Reactions of 4-Benzoyl-1,5-Diphenyl-1H-Pyrazole-3-Carboxylic Acid and Acid Chloride with 2,3-Diaminopyridine

The 1H-pyrazole-3-carboxylic acid 2 was converted in good yield (69%) into the corresponding 1H-pyrazole-3-carboxamide 5 via reaction of the acid chloride 3 with 2,3-diaminopyridine (4). A different product, the 3H-imidazo[4,5-b] pyridine derivative 6, was formed from the reaction of 3 with 4 and base in benzene for 5 hours. The structures of the synthesized compounds were determined spectroscopically. The mechanism of the reaction between 3 and 4 was examined theoretically.

The structure--antituberculosis activity relationships study in a series of 5-(4-aminophenyl)-4-substituted-2,4-dihydro-3h-1,2,4-triazole-3-thione derivatives. A combined electronic-topological and neural networks approach.

Antituberculosis activity of several 5-(4-aminophenyl)-4-alkyl/aryl-2,4-dihydro-3H-1,2,4-triazole-3-thiones (1-9) and their thiourea derivatives (10-31) were screened for their antimycobacterial activities against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system. Of the synthesized compounds, 10-12, 30 were the most active derivatives exhibiting more than 90 % inhibition of mycobacterial growth at 12.5 microg/mL. Structure-activity relationships study was performed for the given series by using the Electronic-Topological Method combined with Neural Networks (ETM-NN). A system of prognosis was developed as the result of training associative neural network (ASNN) using weights of pharmacophoric fragments as descriptors. Descriptors were calculated by the projection of ETM compound and pharmacophoric fragments on the elements of Kohonens self-organizing maps (SOM). From the detailed analysis of all compounds under study, the necessary requirements for a compound to possess antituberculosis activity were formulated. The analysis have shown that any requirements violation for a molecule implies a considerable decrease or even complete loss of its activity.

Investigation of structure–activity relationship on 17-spirolactone derivatives: the electronic-topological approach

Sixty steroid homologues belonging to a series of 17-spirolactone derivatives such as aldosterone antagonists were investigated by electronic-topological method (ETM). Activity features Ph1-Ph3 that also are called pharmacophores were revealed. The pharmacophore Ph1 consists of two oxygen atoms and four carbon atoms. The mineralocorticoid activity appeared to be affected by the distance between the two oxygen atoms. Features AP1-AP3 that are characteristic of inactive compounds (or anti-pharmacophores) were also revealed. Comparative analysis of molecules that include either pharmacophores or anti-pharmacophores was carried out.

Inhibition Effects of 4-Phenyl-3-Thiosemicarbazide on the Corrosion of Aluminum in 0.1 M HCl: Theoretical and Experimental Studies

Abstract The inhibition effects of 4-phenyl-3-thiosemicarbazide (PT) on the corrosion of aluminum in 0.1 M hydrochloride acid (HCl) solution at 298 K to 343 K using potentiodynamic polarization hav...

The Investigation of Structure-Activity Relationships of Tacrine Analogues: Electronic-Topological Method

In this study we investigated the structure-activity relationships by using the Electron- Topological Method (ETM) for a class of AChE inhibitors related to tacrine (9-amino-1,2,3,4-tetrahydroacridine) and 11 H-Indeno-[1,2-b]-quinolin-10-ylamine that tetracyclic tacrine analogues, a drug currently in use for the treatment of the AD. Molecular fragments being specific for active and inactive compounds were revealed by using ETM. The result of testing showed the high ability of ETM in predicting the activity and inactivity in investigated series.

Bis(amino)phosphines Derived From N-phenylpiperazine and N-ethylpiperazine: Synthesis, Oxidation Reactions, and Molybdenum Complexes

Functionalized bis(amino)phosphines that are the type PhP(NR2)2 (1,2) have been synthesized by treating PhPCl2 with N-phenylpiperazine or N-ethylpiperazine. Ligands react with aqueous hydrogen peroxide, elemental sulfur, or selenium to give the corresponding chalcogenides (3–8) in good yield. The molybdenum complexes of the bis(amino)phosphines (9,10) have been obtained. All of the compounds obtained in good yields and they were characterized by IR, NMR, microanalysis, and also quantum chemical calculations such as HOMO-LUMO energies, Mulliken charges, and dipole moment for compounds 1–8 and complex 9 were carried out by using B3LYP/6-31G(d,p), a version of the DFT method with standard Gaussian 09 software package program.

Inhibition Performance and Adsorptive Behavior of Three Amino Acids on Cold-Rolled Steel in 1.0 M HCl—Chemical, Electrochemical, and Morphological Studies

Three selected amino acids, namely, serine (Ser), threonine (Thr), and glutamine (Glu), were tested as corrosion inhibitors for cold-rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) solutions at different temperatures (283 K to 333 K). Chemical (weight loss) and electrochemical (Tafel polarization) methods were used in this study. Electrochemical frequency modulation (EFM), a non-destructive corrosion measurement technique that can directly give values of corrosion current without prior knowledge of Tafel constants, was also used. Experimental corrosion rates determined by the Tafel extrapolation method were compared with those obtained using the EFM technique and the weight-loss method. Morphologies of the corroded and the inhibited surfaces were studied by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM). Tafel plots showed that the three tested amino acids act as mixed-type inhibitors. The three tested amino acids appeared to function through adsorption following the Tem...

Behavior of furnace black types in cis polybutadiene rubber (CBR) compounds and changes in the rheological properties of SBR-1502/CBR-1203 types of rubber compounds

Six different compounds were prepared by using CBR-1203 type of cis polybutadiene rubber and SBR-1502 type of styrene butadiene rubber in different proportions, keeping fixed the total rubber quantity specified in the standard testing recipe, and the rheological properties of the subject compounds were measured. Also, 27 different compounds were prepared with CBR-1203 type of synthetic rubber using furnace blacks having different structures (DBP absorption value) and surface areas (iodine adsorption value), classed as N-220, N-330, N-550, N-660 by ASTM, and furnace blacks having different structures but similar surface areas, classed N-326, N-330, N-347, by changing the standard testing recipe proportions. Physical and rheological tests were carried out and the results compared.

Theoretical Study and Comparasion of Bent's Rule with Hardness and Polarizibility for SF4, SF4O, PCl4F, PCl3F2, PCl2F3, PCl2F4 Molecules

Electronic parameters such as HOMO-LUMO energies, Mulliken charges, dipole moments for different isomers of SF4, SF4O, PCl4F, PCl3F2, PCl2F3, PCl2F4 molecules have been carried out at the MP2 level of theory using 6-31G(d), 6-311G(d,p) basis sets by applying Gaussian 03 Revision B-04. Maximum hardness and minimum polarizability have been calculated to see the consistency with the Bent rule. According to Maximum Hardness Principles (MHP) and Minimum Polarizability Principles (MPP) most stable structure can be predicted if they have different isomers. We have investigated how bond orbitals change for studied molecules by natural bond orbital (NBO) analysis, as well. There is agreement between our results and experimentaql results on the dipole moments and structures of the phosphorus chlorofluorides obtained by IR and Raman vibrational data, NMR measurements and 35Cl pure quadrupole resonance frequencies reported earlier by Holmes aand coworkers.