Duran Karakaş

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+).

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.

Force constant calculations for octahedral complexes of the type M(CO)5L, based on the CO-factored force field

Abstract Using the maximum value of the sum of the interaction constants, the CO-factored force field of octahedral M(CO)5L molecules was solved to give the relations which allow direct calculation of force constants from CO stretching frequencies of the all-12C16O molecule. The force constants calculated by these relations were used to predict CO stretching frequencies of isotopically enriched species of some complexes of the type M(CO)5L. The results obtained showed that there exists a very good agreement between observed and calculated frequencies. This led us to conclude that the solution presented for the force field of M(CO)5L molecules is a valid solution.

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.

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.

Synthesis, characterization and non-linear optical properties of two mononuclear Cu(II) complexes of 2,6-bis(1-butylbenzimidazol-2-yl)pyridine

Abstract Two copper(II) complexes, [Cu(L)(N3)2]·MeOH and [Cu(L)(NCS)2]·MeOH, were prepared and characterized by spectroscopic, analytical, and quantum chemical studies, where L is 2,6-bis(1-butylbenzimidazol-2-yl)pyridine. X-ray quality crystals of [Cu(L)(N3)2]·MeOH were obtained by slow evaporation of MeOH solution of the complex. Molecular structure of [Cu(L)(N3)2]·MeOH was determined by X-ray crystallography. The asymmetric unit contains one [Cu(L)(N3)2] and one MeOH molecule. Cu(II) in [Cu(L)(N3)2]·MeOH is five-coordinate, bonded to five nitrogens (three from L and two from two azide anions). Coordination geometry around Cu(II) center is distorted square-pyramidal with τ value of 0.065. Optimized geometries, IR spectra, and non-linear optical properties of the complexes were obtained by computational studies based on density functional theory (DFT) with M062X method. NLO properties of these complexes were investigated computationally and both complexes exhibit better NLO properties than urea.

A new method for assigning the CO stretching bands in cis-disubstituted octahedral metal carbonyl complexes

Abstract The paper describes a method for assigning the CO stretching bands in cis -disubstituted metal carbonyls of the types L 2 M(CO) 4 , (LL)M(CO) 4 , LL′M(CO) 4 and (LL′)M(CO) 4 . The method was based on the parameter δ , defined as δ =( λ 1 − λ 2 )/( λ 1 + λ 2 −2 λ 4 ) where λ 1 , λ 2 and λ 4 are the λ parameters of the a 1 (1) , a 1 (2) and b 2 modes, respectively. For a large number of complexes with the above general formulas, the average value of δ was found to be 0.62, with a standard deviation of 0.02. It was shown that this range of δ can be used as a criterion of the correct band assignment for the complexes understudy.

Structural, Spectroscopic and Activity Calculations on Methanesulfonylhydrazone Derivative Chromium Pentacarbonyl Complexes

The thiophene-2-carboxyaldehyde methanesulfonylhydrazone (msh1), 2-acetylthiophene methanesulfonylhydrazone (msh2) and 2-acetyl-5-methylthiophene methanesulfonylhydrazone (msh3) ligands, a heteroatomic methanesulfonylhydrazone derivative, was optimized by using HF and DFT (B3LYP) method with 6-31G(d,p) basis set. The calculated IR spectra for msh1, msh2 and msh3 were compared with experimental data and the suitability of the calculation methods was discussed. LANL2DZ and GEN basis sets were used for calculations of chromium pentacarbonyl complexes containing msh1, msh2 and msh3 ligands. According to the experimental IR spectra the most appropriate method and basis set was determined. Structural parameters of ligands and complexes were predicted. To investigate the biological activities of ligands and complexes, some activity descriptors were obtained from optimized structures. Molecular electrostatic potential (MEP) maps of the mentioned ligands and complexes were examined and active sites were determined. The molecular docking study of ligands and complexes with Bacillus cereus (PDB ID=5V8E), Staphylococcus aureus (PDB ID=1BQB), and Candida albicans (PDB ID=1AI9) were performed.

Investigation of Structural, Electronic and Biological Properties of Two Zn(II) Complexes with Pentaaza Macrocyclic Schiff-Base Ligand: A DFT Approach

Two zinc(II) complexes, [ZnL1Br]+ (1), and [ZnL2]2+ (2), are optimized by using density functional theory at B3LYP method with mix basis sets which are LANL2DZ/6–31G(d,p) and LANL2TZ+/6–31++G(d,p) basis sets. L1 and L2 are pentadentate macrocyclic Schiff-base ligands containing piperazine moiety. The optimized structures and structural parameters are obtained by using each basis set. IR and UV–VIS spectra of complex (1) and (2) are investigated in detail. NLO properties of Zn(II) complexes are investigated and it is found that NLO properties of complex (2) is better than complex (1). Solvent effects on biological activity are investigated in gas phase, water and chloroform for studied complexes and no solvent effects are monitored for complex (1) and (2). Biological reactivity of complex (1) is higher than that of complex (2).