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Semi-rigid poly(imide-carbonate)s with high inherent viscosities were synthesized in high yields by melt polycondensation of the monomer N,W-bis(6-hydroxyhexyl)pyromellitdiimide and/or 6,6'-(4,4'-bipheny1ylenedioxy)dihexanol with alkylene bis(pheny1 carbonate)s (m = 6, 8, 10 and 12). The monomer was prepared by deacetylation of an intermediate diacetylated compound derived from the condensation of pyromellitic dianhydride with 6-aminohexanol followed by cyclization with acetic anhydride. The resulting polymers were characterized by ETIR and I3C NMR measurements and elemental analyses. The thermal and mesomorphic properties were evaluated by polarizing microscope observation, DSC measurements and powder X-ray analyses. The polymers showed very good solubilities in organic solvents such as chloroform and 1,4-dioxane. Flexible and tough films were cast from the chloroform solutions. All the polymers have low glass transition temperatures below room temperature which decreased with increase of the aliphatic spacer lengths. Most of the polymers display no thermotropic liquid-crystalline properties, but only the biphenyl unit-rich copolymer exhibits a nematic melt. It is suggested that the mesogenic character of the pyromellitimide ring is very low. *) Systematic IUPAC name of pyromellitic acid: 1,2,4,5-benzenetetracarboxylic acid. 0 1992, Hiithig & Wepf Verlag, Base1 CCC 0025-1 16X/92/$05.00

The reductions of 1-(1) and 2-phenoxynaphthalene (2) to their respective radical anions were observed at -2.42 and -2.48 V vs SCE. Cyclic voltammetric and chronoamperometric studies indicate that both radical anions have half-lives that are greater than 100 s in dry iV,7V-dimethylformamide. Controlled-potential electrolysis of the ethers resulted in relatively slow, regioselective carbon-oxygen bond cleavage to produce phenol and naphthalene. The intermediacy of the naphthyl radical or the naphthyl anion in the reductive pathway was tested by the use of an intramolecular radical trap in the form of a 2-(3'-butenyl) substituent, i.e., 2-(3'-butenyl)-l-phenoxynaphthalene (3). Formation of 1 -methylbenz[e]indan (4) upon the electrochemical reduction of 3 in the absence and presence of D20 confirmed the presence of the 2-(3,-butenyl)naphthyl radical in the radical-anion cleavage mechanism. Reduction of the phenoxynaphthalenes with Na/F1MPA in tetrahydrofuran resulted in slow regioselective cleavage while reduction with Na-K alloy/tetraglyme quantitatively cleaved the ether bond more rapidly. The intermediacy of the naphthyl anion, which is produced via the ether dianion in the Na-K alloy reduction, was demonstrated by the reduction of 3 at -78 and 0 °C. Reduction of 3 at -78 °C produced only 2-(3'-butenyl)naphthalene ( 5) whereas reduction at 0 °C produced both 5 and 4, the latter by anionic cyclization.