A series of polyethoxylated amphiphatic palladium catalysts with two-chain polar head have been synthesized and applied in Suzuki polycondensation(SPC)

all of which are easy to dissolve in organic solvents for SPC(toluene

THF

DMF) and stable in atmospheric environment.Model polymer poly(9

9-dioctylfluorene)(PFO) with Mn=7104 could be obtained using amphiphatic palladium catalysts with better hydrophilicity(Cp3 and Cm4) in toluene/H2O system

which were comparable to the results with addition of phase-transfer agent(Aliquat 336).As the hydrophilicity of the amphiphatic catalysts got even stronger(Cp4)

higher molecular weight(Mn ca. 1105) PFO could be achieved.From the GPC chromatograms for polymerization runs with different amphiphatic catalysts in toluene/water system

amphiphatic catalysts with longer polyethoxyl chain could be used to achieve higher molecular weight.And two peaks could be found in the GPC curves for polymerization runs with amphiphatic catalysts with strong enough hydrophilicity

which means there are high molecular portion and low molecular portion comprising the polymer product

indicating the process might follow two different reaction pathways.One is following the traditional way

base or the boronate anion in water phase are difficult to contact the oxidation addition intermediate in the organic phase

just resulting in low molecular weight polymers.The condition could be improved when the other way followed

the transmetalation step accelerated with the aid of the polyethoxyl chain anchoring to the two-phase interface

the catalytic cycle process could be improved and higher molecular weight polymers could be achieved.The bad performance of these neutral amphiphatic catalysts in THF/H2O and DMF/toluene indicates that the long polyethoxyl chain goes against the oxidation addition step in polar solvents

due to the rather good hydrophilicity of catalysts.