ACYCLIC DIENE METATHESIS (ADMET) POLYMERIZATION - SYNTHESIS OF UNSATURATED POLYTHIOETHERS

A series of symmetrical alpha,omega-unsaturated thioethers have been polymerized under standard acyclic diene metathesis (ADMET) conditions. Poly(thio-3-hexene-1,6-diyl)(7), poly(thio-4-octene-1,8-diyl) (8), and poly(thio-5-decene-1,10-diyl)(9) were synthesized in bulk from the corresponding bis(alkenyl) sulfides (2, 3, and 4, respectively) in the presence of the catalyst Mo(CHCMe2Ph)(N-2,6-C6H3-i-Pr2)(OCMe(CF3)2)2 (5). Poly[(thio-5-decene-1,10-diyl)-co-(1-octenylene)] (10) was prepared from the copolymerization of bis-(5-hexenyl) sulfide (4) and 1,9-decadiene. The polymerizability of the alpha,omega-dienes appears to be a function of the number of methylene spacers between the sulfur moiety and the terminal olefin. In the case of the monomer diallyl sulfide (1), where one methylene spacer is present, no polymerization was observed in the bulk, but rapid cyclization to 2,5-dihydrothiophene (6) was observed in solution. All polymers were characterized by H-1 NMR, C-13 NMR, and IR spectroscopies as well as elemental analysis, GPC, TGA, and DSC. These results suggest that sulfur-containing polymers are now accessible via ADMET polymerization.