Journal of Physical and Theoretical Chemistry
Volume:17 Issue: 1, Spring and Summer 2020

A new Kinetic Spectrophotometic method for the Determination of trace amount Sulfacetamide Drug into real samples has been described based with silver nanoparticles starch-capped sensor, by sodium borohydride. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 347.5 nm. 1.0×10-2 molL-1 silver nanoparticles starch-capped sensor, 2.0×10-3 mol L-1 sodium borohydride at 25oC, calibration graph in the range of 0.1-6.0 μg L-1 sulfacetamide drug. The absorbance is linear from 0.02 up to 8.0 μg L−1 in aqueous solution with repeatability (RSD) of 0.9% at a concentration of 6.0 μg L−1 and a detection limit of 2.3 μg L−1 by the fixed-time method of 7.0 min. The relative standard deviation for 6.0 μg L-1 sulfacetamide drug is %95. No serious interference was identified. The applicability of the method was demonstrated by the determination of the Sulfacetamide drug in urine and blood samples.

Organometallic complexes offer potential for design as anticancer drugs. A quantitativemodel that discriminates anticancer compounds from the inactive ones in a training series wasEquilibrium of the reaction of molybdenum (VI) with l-histidine have been studiedin aqueous solutions at pH range of 4-8, using spectrophotometry and optical rotationmethods at constant ionic strength of 0.15 mol.lit-1 of sodium perchlorate at c 0 25  0.1 .L-histidine has been proposed to be present at the active site of a number of enzymes. Inaddition, as a part of cytochrome-c, it is apparently involved in the electron transport systems.Also, molybdenum (VI) is an essential component of several enzymes which catalyzereactions. In this project, we have determined the pH in which the complex is formed usingspectrophotometry and polarimetry techniques. The molar ratio of metal to ligand in amolecule of complex was 1:1, and the stability constant of this complexation process has beendetermined by polarimetry and spectrophotometry methods at different wavelengths. Thestability constant decreases upon increasing the pH over 6, so the stability constant ofcomplex of Mo (VI) with l-histidine has been determined at pH=5.8. We have used literatureto propose a structure for the complex molecules. So the proposed structure is an octahedralwith a central core consists of MoO3 with three binding sites for complexation. Thus, histidineas tridentate ligand can made a chelate with the metal, through the oxygen of carboxylicgroup, the nitrogen of amides group and the charged nitrogen of imidazole ring donors.

Increasing the molecular accumulation and density of high-energy substances have a determinative role in improving the performance and intensity of energy release. Therefore, it is possible to increase the density of high-energy materials if the high-energy molecules can be arranged around a metal core as coordinated molecules. The aim of this project was to synthesize energetic complexes of cyclo molecules with Cobalt nuclei, cyclo molecule reacted with metal nitrate salts. To this purpose, cyclo was reacted with Cobalt nitrate with molar ratio of 1:4 in DMF solvent, respectively. To evaluate the ligand-to-metal ratio and characterize the structure of complex as well as to ensure proper complex synthesis, optical microscopy, UV-Vis spectroscopy, FT-IR spectroscopy and thermal gravimetric analysis (TGA) were used. The thermal decomposition process of the synthesized complexes compared to the pure cyclo showed that the cyclo coordinated to the central metals of nitrate intermediates, a two-step thermal decomposition process, converted to one step process. The energy released during the thermal decomposition process of Cobalt nitrate complexes is 649.3822 J/gr.

A [3+2] cycloaddition (32CA) reaction among a thiocarbonyl ylide (TCY 2) with (E)-4,4,4-trifluoro-4-phenylbut-3-en-2-one (TFB 4) as an electron-deficient enone in tetrahydrofuran (THF) were studied within the Molecular Electron Density Theory (MEDT), at the DFT-B3LYP/6-31G(d) computational level to analysis energetics, selectivities, and mechanistic aspects. The reaction can progress in four competitive 32CA reaction paths. An analysis of the density functional theory (DFT)-based reactivity indices shows that TCY 2 is a strong nucleophile and TFB 4 is a strong electrophile. Parr function analysis at the reactive sites of reagents demonstrates that the C1-C6 attack should be the more favorable regioselective channel in 32CA reaction of TCY 2 toward TFB 4. An exploration of computed relative Gibbs free energies implies that the studied 32CA reaction leads to thiolanes 4 as the unique cycloadduct, in complete agreement with the experimental outcomes. The global electron density transfer (GEDT) value at the energetically most preferred transition state TS 1 reveals that this pseudoradical type (pdr-type) 32CA reactions exhibits a notable polar character.

Today, the use of natural polymers and their replacement with synthetic polymers in various fields of science has attracted much attention. Reducing the associated risks, easy access, and being cost-effective are among the advantages of using natural polymers compared to the synthetic polymers. In this research, the destruction of amylopectin in the presence and absence of titanium dioxide nanoparticles was investigated. The main objectives of this research include the replacement of the synthetic polymer materials with natural polymeric materials in order to produce new raw materials with high performance and less pollution to be used in various fields of science, particularly pharmaceuticals and medicine, and also studying its destructive properties. A comparison of the analysis methods besides adding titanium dioxide and other chemical additives would provide a variety of possible modes to study on the properties of this polymer. To investigate the viscosity of experimental solutions, the techniques such as XRD and FT-IR were used to detect the degradation rate of the samples.

In recent decades, the use of nanofluids has attracted much attention due to its application in various fields such as medical and industries like oil and gas. The combination of nanoparticles with base fluids and its type can produce different results depending on the characteristics of the nanoparticles, one of which is the effect of changes in the viscosity and thermal conductivity of the nanofluids. In this regard, the present study aimed to experimental investigation of alumina nanoparticles composite on the viscosity and thermal conductivity of water and ethanol nanofluids was performed. The nanofluids were prepared by combining of the Al2O3 nanoparticles with aluminum triisopropylate and then dispersed in the base fluids using an ultrasonic device. In this study, Al2O3 particles and triisopropylate aluminium with a partial thickness of about 2 nm were used with different of volume and concentration ratios in different temperatures. Experimental results of this study about the thermal conductivity and viscosity of water-Al2O3 and ethanol-aluminum triisopropylate nanofluids exhibited that the nanofluids have higher thermal conductivity than the base fluids. The concentrations of nanoparticles are very low; however, the thermal conductivity of nano-fluids causes a significant increase in the volume of nanoparticles. The measured thermal conductivity and viscosity of nanofluids showed that these parameters increased with the volumetric concentration of nanoparticles and also the higher temperature, the lower viscosity and the higher thermal conductivity.