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.
Formations of chiral photopyridones(2) from 2-pyridones(1) are very interesting as examples of photoreaction theory, chiral syntheses and solar energy-storage. We here report chiral 2 preparation from 1 with chiral hosts((l)-3 etc.), and molecular orbital analyses of the energy and stereochemical changes.The synthesized chiral imido-amido host (l)-3 etc. produced complexes 1a·(l)-3 etc., to follow the photoreactions to give (R)-2a.Molecular simulation of the excited singlet state (S1) 1* showed that 1* exists as two conformers (1*Φ(+) and 1*Φ(-): ΔEK=8∼9kcal/mol) to be non-planer and enantiomeric, and 1*Φ(+) was shown to go to (R)-2a via three kinds of potential energy surfaces(PES).Formation of (R)-2a by photoreaction of the 1a·(l)-3 complex was simulated to be introduced to 1*Φ(+)·(l)-3 by S1 excitation of the 1a·(l)-3, followed by decrease of the r3-6 and deactivation to (R)-2a. We then verified that molecular simulation of similar 1a·(d)-3 singlet excitation gives (S)-2a, and that molecular simulation of 1a·6 host-guest experiments by Bachs´ also gives (R)-2a.Moreover we checked the large energy-storage, substituent effect, and acid-catalyst effects for 1⇔2 recycle reactions, and propose new solar energy-storage and photosensitized systems.
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.
Although chemometrics has become widely used recently for analyzing experimental chemical data, there exist in only a few instructions for the proper usage of chemometrics other than some introductory books. As the third step of chemometrics calculations with Microsoft Excel (Excel), the multiple regressions for quantitative analysis are performed on a worksheet. An Excel worksheet for generating absorption spectra is constructed. On other worksheets, quantitative analyses by two different multiple regression methods, which are based on the Lambert-Beer rule (in this paper, this method is called “Lambert-Beer analysis”: “LBA”) and on fundamental multiple linear regression (MLR), are executed using the generated spectra. The performances of quantitative analysis between these methods are compared. The obtained results indicating that LBA has higher performance for the spectra with noise, on the other hand MLR has higher performance for the spectra of samples including the unknown component.