SYNTHESIS OF 7,7,8-TRIS(ALKOXYCARBONYL)-8-CYANOQUINODIMETHANES AND THEIR AMPHOTERIC POLYMERIZATION BEHAVIOR IN ALTERNATING COPOLYMERIZATION

7,7,8-Tris(alkoxycarbonyl)-8-cyanoquinodimethanes (1) with ethoxy (1a) , methoxy (1b), isopropoxy (1c), butoxy (1d), and tert-butoxy (1e) alk oxy groups were successfully prepared as pure, isolable yellow crystal s. Compounds 1a and 1e formed charge-transfer complexes not only with styrene (St) but also with 7,7,8,8-tetracyanoquinodimethane (TCNQ), in dicating that 1a and 1e exhibited an amphoteric polar character in the charge-transfer complex formation. When 1a-e were dissolved in basic polar aprotic solvents such as acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and dimethyl sulfoxide, 1a-d, but not 1e, spon taneously polymerized to give polymers. Compounds 1a-e were homopolyme rizable with 2,2'-azobis(isobutyronitrile) (AIBN) and butyllithium but not with boron trifluoride etherate. Compound le had a very poor poly merizability compared with 1a-d, probably due to the steric hindrance of the tert-butyl group. Homopolymerizable compound la copolymerized w ith St in the presence of AIBN to obtain the monomer reactivity ratios r(1a) = 1.62 +/- 0.28 and r(St) = 0.005 +/- 0.01 at 60 degrees C and Q and e values of Q = 30.5 and e = +1.40, indicating that 1a is highly conjugative (highly reactive) and electron-accepting and copolymerize d with acceptor monomer TCNQ in a perfectly alternating fashion. Poorl y homopolymerizable compound 1e also copolymerized not only with donor monomer St but also with acceptor monomer TCNB in a perfectly alterna ting fashion, indicative of the amphoteric polymerization behavior of 1e. Compounds 1a and 1e were found to be isolable 1,4-quinodimethane m onomers which exhibited amphoteric behavior in the charge-transfer com plex formation as well as in the alternating copolymerization.