Alireza Akbari

Synthesis, structural, and thermal analyses of copper(II) and oxido-vanadium(IV) complexes of 4-bromo-2-(((5-chloro-2-hydroxyphenyl)imino)methyl)phenol

Reaction of 4-bromo-2-(((5-chloro-2-hydroxyphenyl)imino)methyl)phenol (H2L) with Cu(OAc)2·4H2O or VOSO4·3H2O and 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) in a 1 : 1 : 1 mol ratio led to [CuL(phen)] and [VOL(bipy)] which have distorted square pyramidal and octahedral geometries, respectively. The compounds were characterized by elemental analyses, FT-IR, UV–Vis, TGA, and X-ray diffraction. Their thermolyses have three stages: phen or bipy removal, separation of H2L minus chloride and bromide of H2L, and complete thermal decomposition to the metal oxide.

A mononuclear diketone-based oxido-vanadium(IV) complex: structure, DNA and BSA binding, molecular docking and anticancer activities against MCF-7, HPG-2, and HT-29 cell lines

A mononuclear oxido-vanadium(IV) complex, [VO(L)2], has been prepared from the reaction of dibenzoylmethane (HL) and VO(acac)2 in a 2 : 1 molar ratio, and fully characterized using elemental analyses, molar conductivity, FT-IR, and electronic spectroscopy. The structure of this compound was also confirmed by single crystal X-ray diffraction. It was found that in the title complex, the metal coordination geometry is described as a distorted square pyramid. DNA binding activities of this complex were investigated using electronic absorption titration, competitive fluorescence titration and cyclic voltammetry studies. The obtained results showed groove binding of the complex to salmon sperm DNA accompanied with a partial insertion of the ligand between the base stacks of the DNA with a binding constant of 2.3 × 103 M−1. In addition, the interaction of the complex with bovine serum albumin (BSA) was studied using electronic absorption and fluorescence spectroscopies at different temperatures indicating a good affinity of the complex for BSA. These experimental results were confirmed by the results of molecular docking. Finally, the in vitro cytotoxicity properties of the synthesized complex against MCF-7, HPG-2 and HT-29 cell lines were evaluated and compared with those of the ligand (HL). It was found that complexation improved the anticancer activity significantly. IC50 values for the V(IV) complex against MCF-7, HPG-2 and HT-29 cell lines were obtained as 7.8, 13.5 and 16.1 μM, respectively.

Complexes with cis-MoO2 unit of new isothiosemicarbazone

A new 5-bromo-2-hydroxobenzaldehyde S-ethylisothiosemicarbazone hydroiodide free Schiff base (H2L) is synthesized and a series of molybdenum(VI) complexes, MoIVO2LD, have prepared where D can be DMF, DMSO and pyridine. The compounds are characterized with molar conductance, FT-IR, 1H NMR, elemental analyses, and UV-Vis techniques. Structures of complexes are determined with X-ray analysis. All experimental results confirmed that H2L is a tridentate bi-deprotonated ligand (ONN), coordinating through phenolic oxygen, azomethine nitrogen, and isothioamide nitrogen. The neutral complexes are distorted octahedral.

Space-time scaling invariant traveling wave solutions of some nonlinear fractional equations

The 4-((E)-(2-((E)-2, 4-dihydroxybenzylideneamino) ethylimino) methyl) benzene-1,3-diol tetradentate ligand, H2L, reacted with PdCl2 to produce the related complex. The complex was characterized by elemental analysis, infrared and electronic spectroscopy, thermogravimetric study, and molar conductance. Furthermore, the fully optimized geometries were calculated using the ADF 2009.01 package. Comparison between the calculated and experimental results covering molecular structures, assignment of fundamental vibrational modes, and thermodynamic properties were investigated. The optimized molecular geometries were compared with the experimental data obtained from X-ray data of a similar complex, which indicated that the theoretical results agree with the corresponding experimental values. The UV-Vis spectrum of the compound was also recorded and some properties, such as HOMO and LUMO energies and λmax , were determined using DFT (PW91) method. The absorption wavelengths were compared with the experimental data.

Synthesis, spectral, DFT and X-ray study of a cis-MoO2 complex with a new isothiosemicarbazone ligand

2,4-Dihydroxybenzaldehyde S-allylisothiosemicarbazone hydrobromide, H2L, reacts with dioxo-molybdenum acetylacetonate in methanol to form a stable complex of dioxomolybdenum(VI). The ligand and complex are characterized with analytical and spectroscopic techniques. Single-crystal X-ray crystallography has been also carried out for the complex, showing it has distorted octahedral geometry. H2L is a tridentate dianionic ligand bonded as an ONN donor to molybdenum. Thermogravimetric analysis of the complex shows MoO3 as the final product above 780 °C. The results obtained from density functional theory calculations for the optimization and frequency analysis are in agreement with the experimental data. Natural bond orbital calculations show that the majority of the electron density of the donors tends to the molybdenum, since the calculated Mulliken charge for the central ion is much lesser than the formal value.

Theoretical Study of Solvent Effects on the Cis-to-Trans Isomerization of [Pd(C6Cl2F3)I(PH3)2]

In this work, the effect of different solvents on the mechanism of the cis-to-trans isomerization of [Pd(C6Cl2F3)(I)(PH3)2] has been investigated theoretically in detail. Using a quantum mechanical approach, different pathways were investigated. A three-pathway mechanism has already been proposed which consists of two PH3-sensitive steps (k3, k4) and one PH3-insensitive (kdiss) step. Since in the k3 pathway the solvent has two types of explicit and implicit effects, this path was investigated for both the gas phase and solvent systems (using the PCM model). In this path, solvents with larger donor numbers (necessary condition) and smaller dielectric constant and dipole moment values (sufficient condition) are more appropriate. In the k4 pathway, the solvent has an implicit effect only, and the smaller are the dielectric constant and dipole moment of a solvent, the more appropriate it is. To find the best solvent, a parameter, called the average activation energy, was defined, which considers the contribution of each path in the mechanism.

X-ray structure and theoretical studies on a palladium(II) Schiff base complex

Treatment of N,N′-bis(salicylidene)-1,2-cyclohexanediamine (H2L) with PdCl2 in the presence of triethylamine afforded [Pd(N2O2)]. Recrystallization in chloroform and acetonitrile (1 : 1) gave suitable crystals for X-ray crystallography. The solid-state structure shows that the environment around palladium is square planar. The structural parameters of the molecule obtained by density functional theory (DFT) calculation in the gas phase and by X-ray diffraction are compared. The Pd(II) Schiff base complex adopts planar geometry by DFT calculation. The coordination site structural parameters, which are obtained from geometry optimization calculation, are close to those from X-ray crystallographic data. The spectral properties such as vibrational frequencies, chemical shifts, electronic excitation and the natural bond orbital analyses of Pd(Salen) are calculated, analyzed and compared with experimental data.

Co(III) and Fe(III) complexes of Schiff bases derived from 2,4-dihydroxybenzaldehyde S-allyl-isothiosemicarbazonehydrobromide

Two new complexes, [Co(L1)(Py)3]Cl0.75Br0.25 (L1=4-hydroxy salicylaldehyde S-allyl-isothiosemicarbazonato-N,N′,O) and [Fe(L2)Cl]·C2H5OH (L2=S-allyl-N1-(4-hydroxy salicylaldehyde)-N4-(salicylaldehyde)isothiosemicarbazide-N,N′,O,O′), have been synthesized and characterized by elemental analysis, FT-IR and UV–vis spectroscopy, and molar conductivity. The solid-state structures of the complexes were also determined by single crystal X-ray diffraction. The iron(III) and cobalt(III) complexes adopt distorted square-pyramidal and octahedral geometries, respectively. The strength of the bonding in these complexes was investigated by thermogravimetric studies with both exhibiting stability with complete decomposition not occurring until ca. 600 °C.

Synthesis, spectroscopy, X-ray crystal structure, and DFT studies on a platinum(II) Schiff-base complex

[PtCl2(SMe2)2] reacts with (N,N′-bis(salicylidene)-1,2-cyclohexanediamine) to give (N,N′-bis(salicylidene)cyclohexane-1,2-diamine)platinum(II). The complex has been characterized by elemental analysis, infrared (IR), UV-Vis, and single-crystal X-ray diffraction. Pt(II) is in a square-planar environment, coordinated by a chelating N2O2 donor. Density functional theory (DFT) calculations such as geometry optimization, vibrational frequency, electronic properties, and natural bond orbital (NBO) have been performed for the platinum compound using the OLYP method at TZP(6-311G*) basis set. The optimization calculation shows that the geometry parameters can be reproduced with the OLYP/TZP basis set. Experimental IR frequencies and calculated vibrational frequencies support each other. Time-dependent DFT has been used for absorption wavelengths and results were compared with experimental data. Moreover, NBO analysis has been performed.

Graphene oxide based solid acid as an efficient and reusable nano-catalyst for the green synthesis of diindolyl-oxindole derivatives in aqueous media

Graphene oxide nanosheets were synthesized from natural graphite powder. The prepared catalyst was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis and ultraviolet–visible spectroscopy. This heterogeneous catalyst was used for the Friedel–Crafts 3-indolylation reaction of isatin with indole derivatives in water as a green media in good to excellent yields. This method has advantages including the use of water as a green solvent, short reaction time, easy workup and excellent yields.