Simulations of alkali metal ion extraction ability using spirobenzopyran derivatives bearing a monoazacrown ether moiety were conducted by molecular dynamics calculation. Previously, our simulation studies had revealed the effects of the alkyl chain length in the spirobenzopyran derivatives on extractability towards alkali metal ions. In this research, the counter anion effects on liquid-liquid extraction were investigated by using 1,2-dichloroethane as an organic phase. The results show that the metal ions were more easily extracted into the organic phase when hydrophobic anions such as picrate and phenolate ions were used as counter anions than when hydrophilic anions such as nitrate and chloride ions were used, regardless of the metal ions and the crown ring size. This tendency is theoretically supported as the general anion effect.
We have developed a novel property estimation equation with a group contribution scheme for molecular properties (boiling points), in the standard condition using a three layers perceptron type neural network and are equipped MolWorks™ with it. 142 groups are newly defined as a set to reproduce the differences of isomers and to realize more accurate predictions than are available with usual methods. 765 data of molecular boiling points are selected for training of the neural network. 953 data were applied to evaluate the efficiency of the equation. The correlation of observed and predicted molecular boiling points by this work is better than the values obtained by Joback's equation. The equation is applicable to estimate a wide thermal range, including high and low temperature regions. Furthermore, the equation well reproduces the differences of boiling points for not only ortho-, meta-, and para- isomers but also for cis- and trans-isomers.
An accurate method for the numerical solution of the eigenvalue problem of the second-order ordinary differential equation for the central-Force-Field problem in quantum mechanics is presented. Firstly, initial values for the eigenvalue and eigenfunction are obtained by using the discretized matrix eigenvalue method. Secondly, the eigenvalue and eigenfunction are solved by using the shooting method. Highly accurate solutions around zero are obtained by using the formal solution of power series expansion. Similarly, highly accurate solutions around infinity are obtained using asymptotic series expansion. These formal solutions are used for the initial value or guess for the shooting method. The initial value problem is solved highly accurately by using the higher-order linear multistep method based on the method of constructing the optimal operators. The eigenvalue is properly corrected by using Ridley’s formula and highly accurate numerical differentiation, integration, and a suitable choice of matching point. The efficiency of the present method is demonstrated by its application to bound states for the Coulomb potential, the Hulthén potential, the Yukawa potential and the Hellmann potential in the central-force-field problems.