Edward Cornwell

NEW IDEA FOR THE TOPOLOGICAL INDEX EVALUATION AND TREATISE MULTIPLE REGRESSION WITH THREE INDEPENDENT VARIABLES: SATURATED HYDROCARBONS USED LIKE A MODEL

In QSRR discipline an easy novel to used parameter was designed (Vc) for evaluated classical topological index (W, 1c, Z, MTI) and two new generation ones (Xu, 1ch). Regression between Vc and 1ch presented a correlation index (r) of 0,9992, a surprising high value in comparison with that founds commonly in QSPR/QSAR discipline. Through Vc parameter, an idea to treatise multiple three independent variable regression is present. Model of 35 saturated hydrocarbons were used

VECTOR DOT PRODUCT USED FOR REDUCED THREE INDEPENDENT VARIABLES OF MULTIVARIATE REGRESSION TO A LINEAR REGRESSION WITH ONE INDEPENDENT VARIABLE: ALCOHOLS USED LIKE A MODEL

ABSTRACT The aim of this work is based in the reduction of independent variables in multivariate regression analysis to one by means a vector dot product (E 3 ). By this way, it is omit the orthogonalized procedure to obtained valid regression equation without co-linearity variables and valid signs supporting each independent variables factor, also by this procedure (E 3 ) it is possible to omit variable reduction process by means the Principal Components Analysis (PCA) and the used of others calibrations techniques in order to reach simples valid regressions functions. The reduction of three independent variables to one by (E 3 ) method, permit to applied linear regression (y = m*x + n) with clear significance on m and n parameters, this not occur in the original three-independent variable parameters regression, if it is not properly treatise. INTRODUCTION In the QSPR multivariate regression equations, the real significance of all factors and signs affecting each independent variable are obtained if orthogonal procedure

CORRELATION STUDY USING SATURATED HYDROCARBONS AS A MODEL, OF THE RETENTION TIME IN GLC AND DIFFERENT PHYSICO-CHEMICAL PARAMETERS

Using a model of 27 saturated hydrocarbons, the logarithm retention times relative to n-hexane were correlated with 11 physico-chemical properties. For all correlations studied, where log trr was used as a dependent variable, the correlation based on log trr vs. critical pressure presented statistical parameters indicating that this relationship is the optimal one within the set being studied. The multi-variable regression studies gave significantly smaller Fisher indices than that obtained in the previously indicated relationship. Principal Component Analysis (PCA) applied to all treated variables indicated that only one linear combination exists with a statistically significant value accounting for almost all of the data variability

ELECTROTOPOLOGICAL STATE MODELING OF STABILITY CONSTANTS OF BINARY AND TERNARY COPPER(II) COMPLEXES WITH A-AMINO ACIDS

The second stepwise formation constants of binary and ternary copper(II) complexes with a-amino acidate ligands are modeled by using four-descriptor sets consisting of three indexes defined as linear combinations of the E-states of some skeletal groups of the different species involved in the formation equilibria, and the logarithm of the statistical factor. Hydrophobicity and basicity properties of the ligands are also described. Results indicate that both hydrophobic interactions and ligand basicities, as differential factors over the sequence of copper(II) complexes, would operate mainly through changes in the stability of the copper(II)-carboxylate bonds

DESIGN OF A QSRR: E INDEX WITH HIGH MOLECULAR INFORMATION CONTENT TO DIFFERENCIATE CIS AND TRANS ALQUENES

Using QSRR modelling, an E index was designed based on the H. P. Schultz MTI index. The E index is a molecular descriptor consisting of a vector and adjacent and distant matrices. Linear regressions were obtained by means of a QSRR - GLC study of a set of 11 cis and 11 trans alquenes characterized by the Ecis, Etrans indices. The correlation indices (r) were 0.97495 and 0.95767 respectively. It was demonstrated that in the linear regressions above, a smaller r was obtained, when the E index was replaced by the refractive molar index taken as reference (IRM). The discrimination E values for cis and trans alquenes were obtained by multiplying by (-1) the distance matrix diagonal elements, corresponding to the carbon atoms that support the π bonds in cis alquenes

A NEW PROCEDURE FOR THE CHEMICAL CONNECTIVITY INDEX APPLICATION

Multiplicative numerical factors (Fc) were calculated to modificated each term (di * dj)-0.5 of 1c v index. The Fc factors were calculated using: nine linear equations system based on the experimental boiling points (B.points,exper.) of nine saturated hydrocarbons, the type of the molecular two-carbon fragment and the number of hydrogen atoms attached to them, that evaluate the chemical graph vertex of the molecule . It was shown for a group of fifty saturated hydrocarbons that smaller differences were obtained between experimental boiling points (B.points,exper.) and those calculated by each (di * dj)-0.5 * Fc contribution to 1cv index , than the differences between boiling points (B.points,exper ) and those calculated by means of the linear correlation f: (B.points,exper. ) AE 1c

ELECTROTOPOLOGICAL STATE STUDIES OF COPPER(II) COMPLEXES WITH alpha-AMINOACIDATES

Descriptor combinations, consisting of the electrotopological state (E-state) indexes of some skeletal groups, the first-order 1c molecular connectivity index and the logarithm of the statistical factor, are employed to describe the second stepwise formation constants of binary and ternary copper(II) complexes with a-aminoacidate ligands. Descriptor sets formed by E-state values of skeletal groups belonging to the chelate rings, 1c and the logarithm of the statistical factor lead to the best regression equations. Results suggest that differences in stability over the series of metal chelates depend mainly upon variations in the coordination tendency of the carboxylate ligand groups