فهرست مطالب hamid golchoubian

Two copper(II) complexes of general formula [CuL2]X2 where L= aminoethylethanolamine and X= ClO4- and Cl- were prepared with a relatively high yield. These complexes were characterized by elemental microanalysis, UV-Vis, and IR spectroscopy techniques, thermal analysis, and molar conductance measurements. The proposed structure of the complex was geometrically optimized, and its structural parameters were calculated based on B3LYP/LanL2DZ level using Density Functional Theory (DFT) that is implemented in the Gaussian09 program and the data were correlated with the current experimental data. The complexes demonstrated reversible halochromism with distinctive color change over the pH range of 0.66 to 13.00 attributed to protonation and deprotonation of the coordinated ligand. The complexes exhibited reversible thermochromic behavior in DMF over a temperature range of room to 140 °C. The complexes showed dark blue at room temperature and yellow-brown at 140 °C, due to the dissociation of the coordinated ethanolic groups of the ligand at the axial position and substitution by solvent molecules at the elevated temperature.

This study presents the design, synthesis, and characterization of a mixed-chelate copper(II) complex, [Cu(L)(acac)(ClO4)]ClO4, where L = 2-[(2-diisopropylamino-ethylamino)-methyl]-pyridine. Various analytical techniques, including elemental analysis, infrared (IR) spectroscopy, single-crystal X-ray diffraction, and molar conductivity measurements, were employed to elucidate the structural attributes of the complex, confirming its deviated square pyramidal geometry. Additionally, the solvatochromic behavior of the complex was investigated. The absorption spectrum revealed a broad, structureless band in the visible region, exhibiting a significant bathochromic shift (red shift) upon changing the solvent. This observation indicates a positive solvatochromic effect, which is ascribed to interactions between the solvent molecules and the weakly bound perchlorate anion in the coordination sphere of the complex. A statistical analysis utilizing the stepwise multiple linear regression (SMLR) method identified the Gutmann donor number (DN) of the solvent as the most influential factor in the observed solvatochromism. Specifically, an increase in the DN value corresponded to a red shift in the absorption of the complex spectrum, indicative of stronger interactions with donor solvents. These findings suggest the potential utility of this complex as a chromogenic sensor for assessing solvent polarity.

Today, biodiesel is being produced and consumed around the world as one of the main sources for replacing fossil fuels. In current research, cobalt doped zinc oxide was used as nanocatalyst to produce biodiesel from soybean oil by transesterification reaction. The nanocatalysts used were first prepared by microwave method and identified by X-ray diffraction (XRD), scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDS). In the next step, the prepared catalysts were used in the reaction of biodiesel production from soybean oil. The produced biodiesel was characterized using nuclear magnetic resonance spectroscopy (NMR) and gas chromatography-mass spectroscopy (GC-MS). Optimal reaction conditions of biodiesel production with cobalt doped zinc oxide nanocatalyst obtained, at 3 h, temperature 60 ˚C, catalyst concentration 3% by weight, and molar ratio of oil to methanol 1 to 41 resulted in 98% efficiency. In another part of this research, microwave radiation with a power of 250 W was used as a source of energy in the biodiesel production reaction which in the presence of 4% by weight of catalyst and molar ratio of oil to methanol 1 to 20 resulted in 91% efficiency in 180 s.

Two nickel(II), and zinc(II) complexes [ML2](ClO4)2 of N-(2-propanamide)-2-picolylamine , L, derived from the condensation reaction of 2-picolylamine with acrylamide were synthesized. The prepared complexes were characterized by elemental analyses, ultraviolet-visible, infrared, 1-H-NMR spectroscopy techniques, and conductivity measurements. The ligand behaves like an NNO donor set, forming octahedral geometries with both Ni(II) and Zn(II) complexes. The nickel complex is halochromic. pH effects on the visible absorption spectra of the nickel complex were investigated in the range of 2-13. Its color change was due to the protonation and deprotonation of labile moieties of the ligand at room temperature. The complex displayed reversible thermochromism in solvents of DMSO and DMF attributed to the dissociation of hemilabile amide moieties from the metal center and substituted by solvent molecules. For the purpose of assigning experimental data to the ligands and complexes, a density function theory calculation on the level of B3LYP/LanL2DZ was performed.

The synthesis and characterization of a dinuclear [LCu(m-OH)2CuL](ClO4)2, complex with a tridentate N,N-diisopropyl,N'-3-propylamide-ethylenediamine hemilabile ligand (abbreviated L) is reported. The dinuclear complex was characterized by elemental analysis, molar conductance, thermal analysis, and spectral studies. In the complex, both copper centers are 5-coordinated and bridged through two hydroxo groups.  Thermo- and solvatochromic behaviors of the complex were investigated by visible spectroscopy. Its reversible thermochromism (blue ↔ green) in acetonitrile solution is due to dissociation and re-coordination of Cu-O(amide) moiety. The solvent-dependent absorption maxima, lmax, was studied by a Stepwise Multiple Linear Regression (SMLR) analysis to determine the best model describing the resulting positive solvatochromism.  The statistical results demonstrated that among different solvent parameters, Donor Number (DN) is a dominant parameter that is responsible for the redshift in the d-d absorption band of the complex by increasing its values.

A symmetric complex [NiL2(H2O)2]Cl2, where L = 2-picolylamine was synthesized and characterized by spectroscopic and structural methods. Single crystal X-ray studies reveal that the Ni(II) center located in a pseudo-octahedral N4O2 environment with bidentate ligands L positioned in basal and two water molecules in the apical position. The complex is solvatochromic, ionochromic and thermochromic. The observed positive solvatochromism in polar solvents is due to the substitution of water molecules by the solvent. The complex demonstrated distinct ionochromism towards cyanide and bromide anions in the presence of other halides and pseudo-halide anions and can be served as a ‘‘naked-eye’’ indicator for the qualitative detection of these anions. The compound showed reversible thermochromism in solid-state from blue to green due to dehydration and hydration process.

Three new heteroleptic copper(II) complexes, [(tmen)Cu(dike)H2O]X where tmen = N,N,N',N'-tetramethylethylenediamine, dike = 2-acetylcyclopentanone anion and X= ClO4- (1), Cl- (2) and Br- (3) are prepared and characterized by elemental analyses, molar conductance measurements and IR and UV-Vis spectroscopy techniques. The complex 1 is fairly soluble in various organic solvents and demonstrates distinctive solvatochromism. However, the solubility of complexes 2 and 3 is less than 1 and their color changes are limited to polar solvents. The influence of the solvent polarity and counter ions on the wave length maxima, max values of the d-d bands of the complexes have been investigated by visible spectroscopy. A multi-parametric equation has been utilized to explain the solvent effect on the d-d transition of [(tmen)Cu(dike H2O)]ClO4 using SPSS/PC software. The stepwise multiple linear regression (SMLR) method demonstrated that the donor power of the solvent plays the most important role in the observed negative solvatochromism of the compound.

The infrared and electronic absorption spectra of a series of new heteroleptic chelated copper (II) complexes [Cu(diamine)(acac)]X that encompass N,N'-1,6-bis(2-bromophenyl)-2,5 diazahexane (diamine), acetylacetonate (acac) and ClO, BPh, PF and BF (X) were studied. The IR, electronic absorption spectra and 4 4 6 4 - - - - the molar conductivity of the newly prepared complexes were presented and discussed. The molar conductivity in dichloromethane reveals a predominance of electrostatic interactions between [C (diamine)(acac)]+ entity and anions, X- that counterbalance the positive charge. The resulting complexes with local symmetry of CuO N 2 2 attain a square-coplanar structure and exhibit the tendency for axial ligation, which is enhanced when an electron-attracting substituent is attached to the phenyl ring of diamine moiety. The tendency for axial ligation is particularly fulfilled when suitable nucleophiles (solvents) with different donor abilities exist, leading to solvatochromism. The solute-solvent interactions are revealed by shifts in the ligand field absorption spectra that are enhanced as the donor power of the solvent increases. Linear dependence of the ligand field absorption maximum on solvent donor number is generally observed.

Solvatochromic properties of a series of bis(3–substituted derivatives of acetylacetone copper(II) (X-acacH, X = Cl, H. CH) complexes were studied. All the complexes demonstrated negative 3 solvatochromism. Among the complexes the Cu(Cl-acac), demonstrated the most solvatochromism. A multi-parametric equation 2 has been utilized to explain the solvent effect on the d-d transition of the complexes using SPSS/PC software. The stepwise multiple linear regression (SMLR) method demonstrated that the donor power of the solvent plays the most important role in the solvatochromism of the compounds.