%0 Journal Article %T Investigation of Catalytic Activity and Kinetics of a Pd/Biphenyl-based Phosphine System in the Ullmann Cross-coupling of Para-substituted Aryl Bromides %J Inorganic Chemistry Research %I Iranian Chemical Society %Z 2538-1865 %A Eavani, Sara %A Azadi, Ehsan %A Joshaghani, Mohammad %D 2020 %\ 12/01/2020 %V 4 %N 2 %P 194-200 %! Investigation of Catalytic Activity and Kinetics of a Pd/Biphenyl-based Phosphine System in the Ullmann Cross-coupling of Para-substituted Aryl Bromides %K Ullmann cross-coupling %K Palladium catalyst %K phosphine %K Hammett correlation %K Mechanistic study %R 10.22036/icr.2020.238735.1077 %X Catalytic activity of a Pd/biphenyl based- phosphine system in the Ullmann cross-coupling reaction of various para-substituted aryl bromides were investigated. The results showed that the bulky electron-rich phosphine efficiently modify the electronic and steric properties of palladium center and promote the cross-coupling reaction. Mechanistic study using the Hammett correlation revels that electron-withdrawing substituents decrease the electron density at the palladium center and decrease the rate of oxidative-addition step such that this step will become the rate determining step (rds). On the other hand, electron-donating groups increase the rate of oxidative-addition step such that the reductive-elimination step will become the rds. %U https://www.inorgchemres.org/article_113931_cb120d69627074529673a1126014aebc.pdf