Synthesis and properties of pyrene-functionalized polyacetylene. A stable helical polymer emitting fluorescence

Pyrene-functionalized chiral N-propargylamide, (R)-HC≡CCH2NHCOCH(CH3)O-1,4-C6H4-OCO(CH2)3-1-pyrenyl (1) was polymerized with (nbd)Rh+[η6-C6H5B−(C6H5)3] as a catalyst to obtain the corresponding polymer with a moderate weight in a good yield. Poly(1) was soluble in CHCl3, CH2Cl2, and THF. The polarimetric and CD spectroscopic data indicated that poly(1) existed in a helical structure with predominantly one-handed screw sense in these solvents. The helical structure was stable upon heating and addition of MeOH. Poly(1) showed very large excimer-based fluorescence compared with 1.