Jabir H. Al-Fahemi

QSPR Models for Octane Number Prediction

Quantitative structure-property relationship (QSPR) is performed as a means to predict octane number of hydrocarbons via correlating properties to parameters calculated from molecular structure; such parameters are molecular mass , hydration energy , boiling point , octanol/water distribution coefficient , molar refractivity , critical pressure , critical volume , and critical temperature . Principal component analysis (PCA) and multiple linear regression technique (MLR) were performed to examine the relationship between multiple variables of the above parameters and the octane number of hydrocarbons. The results of PCA explain the interrelationships between octane number and different variables. Correlation coefficients were calculated using M.S. Excel to examine the relationship between multiple variables of the above parameters and the octane number of hydrocarbons. The data set was split into training of 40 hydrocarbons and validation set of 25 hydrocarbons. The linear relationship between the selected descriptors and the octane number has coefficient of determination , statistical significance , and standard errors . The obtained QSPR model was applied on the validation set of octane number for hydrocarbons giving and .

QSPR study on nematic transition temperatures of thermotropic liquid crystals based on DFT-calculated descriptors

The individual correlations between nematic transition temperatures and the molecular descriptors derived from density functional theory (DFT) method are investigated. Significant quantitative structure–property relationships (QSPRs) for TN of a set of 42 theromtropic liquid crystal were established through principle component analysis (PCA) and multiple linear regression (MLR). A promising six-descriptor linear model with good statistical fitting and predicting capability were developed with the help of DFT. The model is based on EHOMO, ELUMO, μ, S, W and X. The reliability of this model is clear from its correlation coefficient (R2 = 0.95) and cross-validation coefficient (R2CV = 0.93).

Simulative aurintricarboxylic acid molecular docking with antitumor activity for its VO(II), Cr(III), Mn(II) and Fe(III) complexes, HF/DFT modeling and elaborated EPR studies

A synthesized aurintricarboxylic acid (ATA) complex was deliberately investigated. Spectral, thermal, theoretical and antitumor studies are accomplished in this study. Elaborated electronic and EPR considerations are introducing parameters support the structural discussion of complexes. Octahedral geometry is proposed for all complexes except VO(II) is a square-pyramidal configuration. Molecular modeling utilizing Gaussian 09 program (HF/DFT) was used to verify the mode of bonding through the optimized geometries as well as essential quantum parameters were calculated using frontier energies (EHOMO & ELUMO). The soft character of the complexes may expect their excellent biological feature. The molecular docking computational achievement displays distinguished bounds of ATA drug with human colorectal carcinoma and human hepatic carcinoma. However, the interaction with human breast carcinoma receptor is completely absent. This behavior may clarify the antitumor activity of the complexes under investigation. The experimental work was supported with docking for carcinoma receptors used experimentally. VO(II) complex displays distinguished inhibition activity toward human carcinoma used. This is pointed to the other important use for ATA drug complexes exceeding the antibacterial field.

Kinetics and Mechanism of Oxidation of Vanillin by Chromium(VI) inSulfuric Acid Medium

The kinetics of oxidation of vanillin (VAN) by chromium(VI) in sulfuric acid medium was studied by a spectrophotometric technique. The reaction exhibited a first order dependence with respect to [Cr(VI)] and fractionalfirst orders with respect to [VAN] and [H+]. Varying ionic strength or dielectric constant of the reaction medium had no significant effect on the oxidation rate. The proposed mechanism includes an intermediate complex formation between vanillin and chromium(VI) before the rate-determining step. The final oxidation product of vanillin was identified by both spectral and chemical analysis as vanillic acid. The suitable rate law has been deduced. The reaction constants included in the various steps of the suggested mechanism have been evaluated. The activation parameters of the rate constant of the rate-determining step of the mechanism and the thermodynamic quantities of the equilibrium constant have been evaluated and discussed.

Experimental and Theoretical Investigation by DFT on the Some Azole Antifungal Drugs as Green Corrosion Inhibitors for Aluminum in 1.0M HCl

The inhibiting power of three compounds of azole antifungal drugs to ward the dissolution of aluminum in 1.0 MHCl solutions was elaborated using chemical, electrochemical and theoretical investigation by DFT. The azole antifungal drugs to minimize the corrosion rate of Al by diminishing the values of weight loss, corrosion current density and double layer capacitance and the values the inhibition efficiency increases. Azole antifungal drugs behaved as mixed inhibitors. The adsorption of these drugs at the interface between the Al and the electrolyte solution are responsible for the inhibition process according to Temkin’s isotherm. The quantum chemical parameters studies supported the sequence of the percentage inhibition efficiency obtained by chemical and electrochemical measurements.