Lipophilicity of Metallic Complexes of 4-Methoxyphenyl - 4' - Chlorobenzoylhydrazine as Estimated from Principal Component Analysis of thin Layer Chromatographic Retention Data

Application of machine learning in developing a quantitative structure-property relationship model for predicting the thermal decomposition temperature of nitrogen-rich energetic ionic salts

While thermal decomposition temperature (T d) is one of the most important indexes for energetic materials, the most common way of determining and evaluating T d requires laboratory experiments that are complicated, time-consuming and expensive. In the present study, the quantitative structure-property relationship (QSPR) model of T d for 21 nitrogen-rich energetic ionic salts was built and used for T d prediction through 13 descriptors and principal component analysis. The relatively small dataset of 21 samples may lead to overfitting. In the case of small datasets, possible overfitting was reduced by the support vector machine to derive the non-linear QSPR model. The obtained correlation coefficient (R 2) of 96.31% and root-mean-square error (RMSE) of 15.72 indicate the relative reliability of the QSPR model developed in this work. Moreover, T d values of 6 newly designed nitrogen-rich energetic ionic salts were predicted using the new QSPR model. The predicted T d values range from 194 to 225 °C, which are better than that of 4-amino-3,5-dinitro-1H-pyrazole (LLM-116: 178 °C), and no. 1, 2 and 5 are comparable to that of the traditional explosive 1,3,5-trinitro-1,3,5-triazinane (RDX: 230 °C), indicating the excellent properties of the designed energetic ionic salts, which can be used for the preparation of potential energetic materials.

Quantum chemical and molecular dynamics studies of imidazoline derivatives as corrosion inhibitor and quantitative structure–activity relationship (QSAR) analysis using the support vector machine (SVM) method

The inhibition performance of 10 imidazoline molecules with number of carbon from 15 to 21 of hydrocarbon straight-chain was studied by weight-loss method and theoretical approaches. The main purpose was to build a quantitative structure–activity relationship (QSAR) between the structural properties and the inhibition efficiencies, and then to predict efficiencies of new corrosion inhibitors. The quantum chemical calculation suggested that the active region of imidazoline molecules was located on the imidazoline ring and hydrophilic group, and active sites were concentrated on the nitrogen atoms of the molecules and carbon atoms of hydrophilic group. A model in accordance with the real experimental solution was built in the molecular dynamics, and the equilibrium configuration indicated that the imidazoline molecules were adsorbed on Fe (110) surface in parallel manner. Descriptors for QSAR model building were selected by principal component analysis (PCA) and the model was built by the support vector machine (SVM) approach, which shows good performance since the value of correlation coefficient (R) was 0.99 and the root mean square error (RMSE) was 0.94. Additionally, six new imidazoline molecules were theoretically designed and the inhibition efficiencies of three molecules were predicted to be more than 86% by the established QSAR model.

Lipophilicity assessment of ruthenium(II)-arene complexes by the means of reversed-phase thin-layer chromatography and DFT calculations

The lipophilicity of ten ruthenium(II)-arene complexes was assessed by reversed-phase thin-layer chromatography (RP-TLC) on octadecyl silica stationary phase. The binary solvent systems composed of water and acetonitrile were used as mobile phase in order to determine chromatographic descriptors for lipophilicity estimation. Octanol-water partition coefficient, logK_OW, of tested complexes was experimentally determined using twenty-eight standard solutes which were analyzed under the same chromatographic conditions as target substances. In addition, ab initio density functional theory (DFT) computational approach was employed to calculate logK_OW values from the differences in Gibbs' free solvation energies of the solute transfer from n-octanol to water. A good overall agreement between DFT calculated and experimentally determined logK_OW values was established (R² = 0.8024–0.9658).

Quantitative structure—retention and retention—activity relationships of some 1,3-oxazolidine systems by RP-HPTLC and PCA

A quantitative structure-retention and retention-activity relationships investigations were performed on the lipophilicities of some 1,3-oxazolidine systems as estimated by RP-HPTLC retention parameters. The classical R(Mo) values were compared with the factors scores obtained by principal component analysis based also onto the TLC retention data. The lipophilicities (R(Mo) and factor scores) were correlated with the theoretical molecular descriptors of 1,3-oxazolidine derivatives providing by the ALCHEMY 2000 software package. The reliability of the factor scores values as lipophilic indices are shown by their significant correlation with the classical R(Mo) values and other molecular descriptors. In addition, the "lipophilicity chart" described by the first two components, and/or the "lipophilicity space" described by the first three components have the effect of separating compounds from each other most effectively from the congeneric (similarity) aspect point of view. Finally, these findings support the idea that the chromatographic process of the investigated compounds in this paper and consequently their partitioning over a bio-membrane are controlled mainly by lipophilicity.

Evaluation of lipophilicity of some benzimidazole and benztriazole derivatives by RP HPTLC and PCA

The lipophilic character of some benzimidazole and benztriazole derivatives was studied. The classical R(Mo) values were compared with the factors scores obtained by principal component analysis (PCA) based also onto the TLC retention data. The very high correlation between the R(Mo) values and slopes (specific hydrophobic surface area) indicated as usually that this group of compounds could be considered as a homologous series independently of their structural heterogeneity. It is emphasized once again that this procedure can not be a rational and objective way for congeneric studies because always there is a high correlation between slope and intercept. The reliability of the factor scores values as lipophilic indices are shown by their high correlation with the classical R(Mo) values. In addition, the 'lipophilicity chart' described by the first two components has the effect of separating compounds from each other most effectively from the congeneric aspect point of view. The most lipophilic compounds appeared to be the benzimidazole derivatives.

Evaluation of the lipophilicity of bile acids and their derivatives by thin-layer chromatography and principal component analysis

The lipophilic character of bile acids and their glyco- and tauro-conjugates was studied. The classical R(Mo) values were measured by means of reversed thin-layer chromatography using a mixture of methanol-water as the solvent system and compared with the factors scores obtained by principal component analysis based also onto the TLC-retention data. The reliability of the factor scores values as lipophilic indices are shown by their high correlation with the classical R(Mo) values. In addition, a better correlation was observed between scores corresponding to the first principal components and the partition coefficients (log P) of bile acids. Finally, the "lipophilicity chart" described by the first two components has the effect of separating compounds from each other most effectively from the congeneric aspect point of view.