Dendrimers as solubilizing groups for conducting polymers: Preparation and characterization of polythiophene functionalized exclusively with aliphatic ether convergent dendrons

The first conducting polythiophene, having only dendritic solubilizers, has been prepared using a Stille coupling approach. The use of second and third generation aliphatic ether convergent dendrons as a solubilizing platform facilitated the preparation of dendrimer-oligothiophene hybrid macromonomers having minimal substitution. Polymers were then prepared via an A₂+B₂ step-growth polymerization between an oligothiophene-dibromide macromonomer and 2,5-bis(trimethylstannyl)-thiophene using Pd(PPh₃)₂Cl₂ as the catalyst. Both the dendrimer size and the dendrimer to thiophene unit ratio were variables that required optimization in order to obtain a solution-processable conducting polymer. Conductivities as high as 200 S/cm were measured for iodine doped thin films of the polythiophene with six thiophene repeat units for each third generation dendron.