Koray Sayin

Theoretical spectroscopic study of seven zinc(II) complex with macrocyclic Schiff-base ligand

Seven zinc complexes, which are [ZnL(1)](2+), [ZnL(2)](2+), [ZnL(3)](2+), [ZnL(4)](2+), [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+), are studied as theoretically. Structural parameters, vibration frequencies, electronic absorption spectra and (1)H and (13)C NMR spectra are obtained for Zn(II) complexes of macrocyclic penta and heptaaza Schiff-base ligand. Vibration spectra of Zn(II) complexes are studied by using Density Functional Theory (DFT) calculations at the B3LYP/LANL2DZ. The UV-VIS and NMR spectra of the zinc complexes are obtained by using Time Dependent-Density Functional Theory (TD-DFT) method and Giao method, respectively. The agreements are found between experimental data of [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+) complex ions and their calculated results. The geometries of complexes are found as distorted pentagonal planar for [ZnL(1)](2+), [ZnL(2)](2+) and [ZnL(3)](2+) complex ions, distorted tetrahedral for [ZnL(4)](2+) complex ion and distorted pentagonal bipyramidal for [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+) complex ions. Ranking of biological activity is determined by using quantum chemical parameters and this ranking is found as: [ZnL(7)](2+)>[ZnL(6)](2+)>[ZnL(5)](2+)>[ZnL(3)](2+)>[ZnL(2)](2+)>[ZnL(1)](2+).

Investigation of Thermodynamic Parameters for Steel Corrosion in Acidic Solution in the Presence of N,N′-Bis(phloroacetophenone)-1,2 propanediamine

AbstractN,N′-Bis(phloroacetophenone)-1,2-propanediamine as corrosion inhibitor for steel in hydrochloric acid has been studied using electrochemical techniques and surface techniques. Results showed that the inhibition occurs through adsorption of the inhibitor molecules on the metal surface. The inhibition efficiency was found to increase with increasing inhibitor concentration and decreased with increasing temperature. Thermodynamic parameters for adsorption and activation processes were determined. Polarization data indicated that this compound acts as the mixed-type inhibitor and the adsorption basically obeys the Langmuir adsorption isotherm. The quantum chemical calculations were performed at the density functional theory level using B3LYP functional with the 6-31G (d,p).

Structural, spectral, NLO and MEP analysis of the [MgO2Ti2(OPri)6], [MgO2Ti2(OPri)2(acac)4] and [MgO2Ti2(OPri)2(bzac)4] by DFT method

Quantum chemical calculations are performed on [MgO2Ti2(OPr(i))6] and [MgO2Ti2(OPr(i))2(L)4] complexes. L is acetylacetonate (acac) and benzoylacetonate (bzac) anion. The crystal structures of these complexes have not been obtained as experimentally but optimized structures of these complexes are obtained as theoretically in this study. Universal force field (UFF) and DFT/B3LYP method are used to obtain optimized structures. Theoretical spectral analysis (IR, (1)H and (13)C NMR) is compared with their experimental values. A good agreement is found between experimental and theoretical spectral analysis. These results mean that the optimized structures of mentioned complexes are appropriate. Additionally, the active sites of mentioned complexes are determined by molecular electrostatic potential (MEP) diagrams and non-linear optical (NLO) properties are investigated.

Computational investigations of trans‑platinum(II) oxime complexes used as anticancer drug

Some platinum oxime complexes are optimized at HF/CEP-31G level which has been reported as the best level for these type complexes in the gas phase. IR spectrum is calculated and the new scale factor is derived. NMR spectrum is calculated at the same level of theory and examined in detail. Quantum chemical parameters which have been mainly used are investigated and their formulas are given in detail. Additionally, selected quantum chemical parameters of studied complexes are calculated. New theoretical IC50% formulas are derived and biological activity rankings of mentioned complexes are investigated.

Investigation of anticancer properties of caffeinated complexes via computational chemistry methods

Computational investigations were performed for 1,3,7-trimethylpurine-2,6-dione, 3,7-dimethylpurine-2,6-dione, their Ru(II) and Os(III) complexes. B3LYP/6-311++G(d,p)(LANL2DZ) level was used in numerical calculations. Geometric parameters, IR spectrum, 1H-, 13C and 15N NMR spectrum were examined in detail. Additionally, contour diagram of frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) maps, MEP contour and some quantum chemical descriptors were used in the determination of reactivity rankings and active sites. The electron density on the surface was similar to each other in studied complexes. Quantum chemical descriptors were investigated and the anticancer activity of complexes were more than cisplatin and their ligands. Additionally, molecular docking calculations were performed in water between related complexes and a protein (ID: 3WZE). The most interact complex was found as Os complex. The interaction energy was calculated as 342.9kJ/mol.

Investigation of structural, electronic properties and docking calculations of some boron complexes with norfloxacin: A computational research

Quantum chemical calculations are performed over BF2R (1), B(NO)2R (2), B(CN)2R (3) and B(CH3)2R (4) [R: 1-ethyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylate]. Mentioned boron complex with fluorine atoms which is BF2R are optimized at HF/6-31+G(d), B3LYP/6-31+G(d) and M062X/6-31+G(d) level and the best level is determined by comparison of experimental and calculated results. The best calculation level is determined as M06-2X/6-31+G(d) level. The other complexes are optimized at this level. Structural properties, IR and NMR spectrum are examined in detail. Additionally, biological activities of mentioned complexes are investigated by some quantum chemical descriptors (EHOMO, ELUMO, I, A, EGAP, η, σ, χ, CP, ω, N, ΔNmax and S) and molecular docking analyses. The interaction energies for complex (1), (2), (3) and (4) are calculated as -480.1, -443.6, -433.6 and -402.1 kJ mol-1, respectively. As a result, it is found that boron complex with fluorine atoms (BF2R) is the best candidate for anticancer drug.

Synthesis, spectroscopic, in vitro cytotoxicity and crystal structures of novel fluorinated dispiroheterocycles: DFT approach

The reaction of azomethine ylide generated in situ from ninhydrin and sarcosine/thiaproline with fluorinated cyclopent[b]indole dipolarophiles in refluxing dioxane and methanol afforded a novel class of fluorinated cyclopent[b]indole dispiroheterocycles via 1,3-dipolar cycloaddition. The crystal structures of 4′-[4-(trifluoromethyl)phenyl]-1′,5-dimethyl-2,3-dihydrodispiro[cyclopent[b]-indol-2,3′-pyrrolidine-2′,2″-indene]-1,1″,3″-trione and 4′-(4-fluorophenyl)-5-methyl-2,3-dihydrodispiro[cyclopent[b]indol-2,3′-pyrrolizidine-2′,2″-indene]-1,1″,3″-trione are reported. New compounds are investigated theoretically via DFT calculations utilizing M062X hybrid function with 6-311++G(d,p) basis sets in vacuum. Results from in vitro cytotoxicity screening are compared with those of standard drugs.Graphical abstract

Indium triflate and ionic liquid-mediated Friedländer synthesis of 2-acylquinolines

ABSTRACT Friedländer synthesis of 2-acylquinolines from the reaction of symmetrical and unsymmetrical 1,2-diketones with 2-aminoarylketones in the presence of indium triflate (In(OTf)3) and ionic liquid gives quantitative yields. Once the reaction was completed, the catalysts can be recovered and subsequently run for next cycles. Results obtained from theoretical studies have been more strengthened by FT-IR, FT-NMR chemical shifts, and structural parameters which were attained with B3LYP/6-31G(d,p) level of theory and the related results were demonstrated with the experimental interpretations. GRAPHICAL ABSTRACT

Pd(II) complexes of novel phosphine ligands: Synthesis, characterization, and catalytic activities on Heck reaction

GRAPHICAL ABSTRACT ABSTRACT Novel phosphine oxides, (((3-methylpyridin-2-yl)amino)methyl)diphenylphosphine oxide (1) and diphenyl((pyrazin-2-ylamino)methyl)phosphine oxide (2), were synthesized and characterized. Phosphines ligands (3 and 4) were obtained by the reduction of 1 and 2 with AlH3, monitored by 31P NMR spectroscopy. Pd(II) complexes of 3 and 4 were synthesized and characterized (5 and 6). The catalytic activity of 5 and 6 was tested on the reaction of styrene with both activated and deactivated aryl bromides in air. The results of the catalytic experiments were discussed through DFT calculations.

Investigations over optical properties of boron complexes of benzothiazolines

Quantum chemical analyses over benzothiazolines and their boron complexes are performed. In calculations, M06-2X method was selected with 6-31 + G(d,p) level. Structural and spectral (IR and NMR) characterization of studied compounds are done in detail. Quantum chemical descriptors (QCDs) are calculated to investigate the optical properties. Furthermore, molecular electrostatic potential (MEP) maps of the studied compounds are calculated by using electro-static potential (ESP) charges. According to QCDs and MEP maps, NLO properties of boron complexes are more than those of benzothiazolines and (Z)-2-((pyridin-2-ylmethylene)amino) benzenethiolatebutane-1,3-bis(olate)boron(III), complex (7), has the most NLO activity in studied compounds. Finally, solvent effect on NLO activity are investigated by calculating UV-vis spectrum in gas phase (ε = 1), toluene (ε = 2.3741), chloroform (ε = 4.7113), methanol (ε = 32.613), water (ε = 78.3553) and n-methylformamide-mixture (ε = 181.56). According to these spectra results, NLO activity mainly increases with increasing of polarizability of media.