Yuehong Zhao

Quantum chemical study on influence of substituents and solvents in reaction complexing ethylene with nickel dithiolene

The influences induced by various terminal substituents and solvents on the reaction mechanism and chemical dynamics of complexing ethylene with Ni dithiolene are theoretically studied by using B3LYP method and Onsager model. It is shown that the reaction should be a two-step process, and the first step is the rate-determining step. We find that the rate constant of the rate-determining step becomes small when the electron-donating ability of the substituents is increased, while it becomes large when the electron-withdrawing ability of the substituents is increased. Subsequently, we consider the solvent effects on the reaction adding ethylene to the simplified hydrogen-substituted nickel dithiolene. It is found that the solvents will make slight changes to the geometries of the reactants, transition states, intermediates and products. However, the corresponding molecular dipole moments become large with the increase of the solvent polarity, which is beneficial to accelerate the reaction. Moreover, we show that, as the solvent polarity becomes large, the activation energies of the reaction decrease exponentially, while the reaction rate constants increase exponentially. These results demonstrate that in polar solvents, the reaction complexing ethylene with Ni dithiolene may become easier and faster to occur, and the product rate is improved. We believe that this research can be seen as a reference for complex and solvent selection in olefin separation process.

The design and development of a project-oriented information system

In this paper, the idea of building a project-oriented information system based upon a specialized information database was discussed. It attempts to provide tools for helping researchers use Internet resources effectively in the course of their research. Based on this idea, a web-based project-oriented information system was constructed. The paper systematically expounds the design and development process of the project-oriented information system. Furthermore, examples of utilizing the project-oriented information system to obtain useful information and suggestions for specific projects were described. According to our discussion and utilization of the system, we believe that building a project-oriented information system can help researchers with their research projects.