Macromolecules, Vol.33, No.13, 4628-4633, 2000
Norbornenyl-substituted thiophenes and terthiophenes: Novel doubly polymerizable monomers
The synthesis and polymerization of norbornenyl-substituted thiophenes (2 and 4) and terthiophenes (3 and 5) are reported. All monomers readily undergo ring-opening metathesis polymerization (ROMP) using the ruthenium catalyst, Cl-2(PPCy3)(2) Ru=CHPh (1). The terthienyl monomers 3 and 5 were directly polymerized onto the surface of a gold electrode via electrochemical oxidation of the capping terthienyl units, while the direct electrochemical homopolymerization of 2 was not achievable, which is consistent with previous literature reports for similarly substituted thiophenes. Chemical polymerization of the terthienyl segments of 3 and 5 using FeCl3 yielded insoluble materials. Finally, polymers obtained from the ROMP procedure were further cross-linked using the oxidative techniques described above, yielding highly networked materials which displayed an increase in thermal stability and electrical conductivity relative to their single-chain polymeric precursors.
Keywords:OPENING METATHESIS POLYMERIZATION;SWITCHABLE HEMILABILELIGANDS;CONDUCTING POLYMERS;NONLINEAR OPTICS;ELECTROCHEMICALPROPERTIES;OLEFIN METATHESIS;DERIVATIVES;ELECTROPOLYMERIZATION;POLYTHIOPHENES;COORDINATION