Synthesis and charge/discharge properties of polyacetylenes carrying 2,2,6,6-tetramethyl-1-piperidinoxy radicals

The 2,2,6,6-tetramethyl-1-piperidinoxy (TEMPO)-containing acetylenic monomers HC equivalent to CC6H3-p,m- (CONH-4-TEMPO)(2) (1), HC equivalent to CC6H3-p,m-(COO-4-TEMPO)(2) (2), (S,S,S,S)-HC equivalent to CC6H3-p,m-[CO-NHCH{COO-(4- TEMPO)}CH2COO-(4-TEMPO)](2) (3), (S,S)-HC equivalent to CC6H4CO-NHCH{COO-(4-TEMPO)} CH2COO-(4-TEMPO) (4), HC equivalent to CC6H4-p-OCO-4-TEMPO (5), HC equivalent to CCH2C(CH3)(CH2OCO-4-TEMPO)(2) (6), HC equivalent to CCH2NHCO-4-TEMPO (7), and HC equivalent to CCH2OCO-4-TEMPO (8) were polymerized to afford novel polymers containing the TEMPO radical at high densities. Monomers 1, 3-6, and 8 provided polymers with average molecular weights of 10000-136500 in 62-99% yield in the presence of a rhodium catalyst, whereas monomers 2 and 7 gave insoluble polymers in 100% yield. The formed polymers were thermally stable up to approximately 274 degrees C according to thermogravimetric analysis (TGA). All the TEMPO-containing polymers demonstrated reversible charge/discharge processes, whose discharge capacities were 21.3-108 A h kg(-1). In particular, the capacity of poly(1)-, poly(4)-, and poly(5)-based cells reached 108, 96.3, and 89.3Ahkg(-1), respectively, which practically coincided with their theoretical values.