Synthesis and Properties of Polyacetylene and Polynorbornene Derivatives Carrying 2,2,5,5-Tetramethyl-1-pyrrolidinyloxy Moieties

Abstract

PROXYL-containing propargyl ester HC⋮CCH2OCO-3-PROXYL (1), N-propargylamide HC⋮CCH2NHCO-3-PROXYL (2), 1-pentyne-4,4-dimethyl ester HC⋮CCH2C(CH3)(CH2OCO-3-PROXYL)2 (3), and norbornene diester monomers NB-2,3-exo,exo-(CH2OCO-3-PROXYL)2 (4), NB-2,3-endo,endo-(CH2OCO-3-PROXYL)2 (5), and NB-2,2-(CH2OCO-3-PROXYL)2 (6) (NB = norbornene, PROXYL = 2,2,5,5-tetramethyl-1-pyrrolidinyoxy) were polymerized to afford novel polymers containing the PROXYL radical at high densities. While 1 and 2 provided polymers with number-average molecular weights of 3300−29 800 in 60−65% yields in the presence of a Rh catalyst, monomers 4−6 gave polymers with number-average molecular weights up to 209 000−272 000 in 90−94% yields with a Ru catalyst. The formed polymers were thermally stable up to ca. 220 °C according to TGA and soluble in common organic solvents including toluene, CHCl3, and THF. Poly(1), poly(2), and poly(4)−poly(6) hardly exhibited absorption above 400 nm, which corresponds with their very light color. The oxidation...