Controlled Palladium(0)-Catalyzed Cross-Coupling Polymerizations Qiao-Sheng Hu, Department of Chemistry, College of Staten Island-City University of New York, Staten Island, NY 10314 Controlled Pd-catalyzed cross-coupling polymerizations, which could generate conjugated polymers with controlled length, may have potential applications in fields such as molecular electronics. Based on the preliminary study of cross-coupling reactions of dihalobenzenes with arylboronic acids on “Preferential Oxidative Addition”, which it is believed to be the key to realize controlled Pd-catalyzed cross-coupling polymerizations, we explored Pd-catalyzed reactions of dihalobenzenes with Grignard reagents including 2,6-dimethylphenylmagnesium bromides. We found with ligands such as phosphines, the reaction proceed via “Preferential Oxidative Addition” mechanism. The reaction proceeded via benzyne intermediates with Pd catalysts such as Pd(OAc)2 to give substituted fluorenes. We have successfully extended the benzyne intermediate hypothesis to the reaction of internal alkynes with 2,6-dimethylphenylmagnesium bromides and two types of organic compounds, substituted indenes and (Z)-tetra substituted ethenes, were efficiently obtained. We have also tested Pd/t-Bu3P-catalyzed Suzuki cross-coupling polymerization of a fluorene-containing monomer and promising result has been obtained.