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A series of copolymers of poly­(arylenevinylene)­s have been prepared by ring-opening metathesis polymerization (ROMP) of cyclic conjugated monomers composed of cyclopenta­dithiophene, bis­(thienyl)­benzo­thiadiazole, or bithiophene using a second-generation Grubbs catalyst and the sequential monomer addition technique. The spectroscopic, electrochemical, and morphological properties of these polymers are tailored by changing the chemical structures and fractions of the monomers. The polymers self-assemble to form microspheres (diameter: 2–5 μm), which act as whispering-gallery-mode optical resonators.

Cyclic conjugated monomers comprising cyclopentadithiophene-vinylene trimers and their polymers on HOPG are observed using STM and AFM. ROMP of the monomers is performed using a Grubbs catalyst. Their STM images exhibit single chains of planar polymers, whereas their AFM images show elongation of the polymer chains on HOPG.

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1993organo-silicon compounds, nonmetal heterocycles organo-silicon compounds, nonmetal heterocycles S 0067 -189Activation of Carbon-Carbon Bond in the Mn-Mediated Cycloaddition Reaction Between Disilacyclobutene and Cyclohepta-1,3-diene.-For the proposal of the mechanism of the title reaction it is demonstrated that the photochemical reaction of (I) with the cycloheptadiene (II) yields (III) (Pna21, Z = 4), which on irradiation with (IV) gives (V), the product of the cycloaddition. Alternatively, ( V) can be obtained by first reacting (I) with (IV) and subsequent irradiation with (II). This suggests that (V) in the cycloaddition reaction results from a C-C cleavage of the cycloheptadiene, a process involving the conversion of a σ-bonded Mn-cyclobutane derivative to a Mn-carbene intermediate. -(CHIANG, H.-J.; LIU, C.-S.; J. Organomet.