Step-growth polymers derived from indene and decafluorobiphenyl. A new polymerization mode for indene

Whereas indene typically polymerizes by 1,2-addition to the olefin, sodium indenide and decafluorobiphenyl react in the presence of sodium hydride in THF to afford a step-growth polymer in which indene is connected via the 1- and 3-positions by 4,4'-octafluorobiphenylene units. The toluene-soluble fraction of the polymer product showed M-n = 3500 and M-w = 5700. The corresponding number-averaged degree of oligomerization of about 10 was confirmed by NMR end group analysis. Abstraction of the remaining acidic indenyl protons using sodium hydride followed by treatment of the deep magenta intermediate with Mn(CO)(5)Br in TRF affords an organometallic polymer in which Mn(CO)(3) fragments are bonded in a pentahapto fashion to the indenyl groups of the 1,3-indenylene-4,4'-octafluorobiphenylene repeat unit.