Molecular modeling on the prediction of silolene-bridged indenyl metallocene catalysts for isotactic polypropylene

Abstract

Two new silolene‐bridged metallocenes for isotactic polypropylene, racemic (1,4‐butanediyl) silylene‐bis (1‐η5‐2‐methyl‐indenyl) dichlorozironium and racemic diphenyl silylene‐bis (1‐η5‐2‐methyl‐indenyl) dichlorozironium, were designed in terms of the mechanism and concept of the activity and selectivity of metallocenes. The predictions on which the designs were based were carried out for four metallocene catalysts through molecular modeling methods such as molecular mechanics and charge equilibrium. In a comparison of the data from three of the catalysts that were successfully synthesized, the predicted orders of the activity and selectivity were consistent. This shows that classical methods such as charge equilibrium are useful in predicting the activity of catalysts. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2232–2238, 2000

Influence of electronic effect on catalytic activity of salicylaldiminato nickel(II) complexes

“…MANCC has a relatively acceptable prediction, which suggests that a reasonable basis might be involved. In our previous study,17, 18 we found that the olefin polymerization activity of early‐transition metal complexes (such as metallocenes) increases with a reduction in the net charge on the central metal. These results are completely consistent with Olivé's concept27 that the stronger electron‐donating ability of a ligand connected to the central metal atom of a catalyst results in a decrease in the net charge on the metal atom and an increase in polymerization activity.…”

Revisiting Benzylidenequinolinylnickel Catalysts through the Electronic Effects on Catalytic Activity by DFT Studies

“…This trend was in line with previous study. [13c],[13e],[13f] However, the slopes of each line were different depend on different substituent R 2 , in which the slopes between complexes 8a – 10a and complexes 11a – 12a were close. This might be due to the electronic negativity of R 2 substituent on these complexes were similar (Me and Et).…”

“…All the charge values are the effective net charges on the Ni metal atom which calculated as previous reports. [13f],[13g],[16a],[16b],[16d]…”

“…By studying the influence of central metal atom charge and steric effect on catalytic activity of Zr‐based metallocenes, Möhring and Coville pointed out that the electronic effect played the dominant role in the factors affecting the polymerization activity . The charge equilibration (QEq) method combined by molecular mechanics has proved to be a good method to correlate polymerization activity with charge value on central metal in previous studies, which was successful in the activity prediction of the early‐transition and also late‐transition metal complex catalysts . With the enhancement of computer performance, to conduct density function theory (DFT) and ab initio calculation on typical transition metal complex catalyst is possible.…”

A Novel Polymer Supported Catalyst for Preparation of Sydiopolystyrene

“…Property of coordinated catalysts for olefin polymerization have great relation with their structure [1,2,3], in addition to syntheses of new catalysts with a design of new ligands, the immobilization, which immobilize a catalyst on a support, is an important method both in theoretical study and industrial applications. The most used supports are inorganic ones such as, MgCl 2 , Al 2 O 3 for Ziegler-Natta catalysts [4,5,6].…”