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Indolo[3,2,1-jk]carbazole (IC) has been synthesised on a gram scale by flash vacuum pyrolysis. In contrast to a previous suggestion, IC is planar and it is also highly fluorescent, with a solution quantum yield of 0.41. Electro-oxidation of IC at a rotating disc electrode resulted in the passage of steady-state currents and the reproducible formation of conducting, redox-active films with constituent species that are also highly fluorescent. Unusually for coupled electroactive N-heterocyclic systems, electrochemical and spectroscopic characterisation revealed the film to consist exclusively of three redox-active (2,2', 5,5' and 2,5' coupled) IC dimers with no polymeric products. Calculations showed this coupling pattern to be consistent with IC radical-cation coupling through the accessible sites of highest unpaired electron density. The unusual combination of a high dimer second oxidation potential and a negligible dimer-dimer coupling rate explains the lack of further coupling. The identities of the dimeric species were confirmed by independent syntheses involving the Suzuki-Miyaura coupling of IC boronic acids as the key step. Electro-oxidation of the IC system therefore offers a ready route to novel conducting, redox-active molecular films and their redox-active, luminescent dimer constituents.

Experimental results from electrochemical e.s.r. on electrodes modified with conducting polymers such as polyaniline, polypyrrole and polythiophene are presented. The results show that the polymer exists in two forms, one stable when it is insulating ( a ) and the other ( p ) when it is conducting. In the conducting region the kinetics of the transformation of the metastable a form into the / 3 form can be followed by e.s.r. It is further shown that in the lightly oxidised films there is a one-to-one correlation between charge injected and e.s.r. spins. These results are explained by a chemical redox model as opposed to a delocalised band.Results from a.c. impedance studies are presented. These results are explained by an equivalent circuit which includes a novel transmission line with differential resistances. Theoretical impedance plots are derived. Experimental results show that the polymer resistance and the resistance of the aqueous pores are equal. Reasons for this finding are discussed.There has been considerable controversy over the nature and dynamics of the charge carriers in conducting polymers. Models range from that of a doped organic semiconductor with well developed bands"* to more chemical models which emphasise the redox chemistry between localised species on the polymer chain.3 In this paper we are concerned with conducting polymers such as polypyrrole, polythiophene and polyaniline. The main experimental techniques we have used are in situ electrochemical e.s.r. and a.c. impedance studies. We will show that the behaviour of the different polymers is similar and may be explained by a chemical model involving localised redox species with two possible conformations of the polymer. A modified transmission line is used to explain the ac data.

Reaction of indole with Br 2 led to isolation of an indole trimer 2, formed by linking the 2-and 3-positions of each indole to form a central aromatic ring, and brominated at the 5-and 6-positions of each indole. The Xray structure of [2]?acetone?2DMF showed p-stacking of the planar aromatic molecules with two different overlap modes with interplanar distances of 3.287 A Ê and 3.378 A Ê . Cyclic voltammetry showed one reversible oxidation for 2 and phosphorescence from frozen ethanol solution was observed. The X-ray structure of the adduct [2][TCNQ] 2 ?4DMSO was determined and showed a mixed stack arrangement where 2 alternates with two adjacent TCNQ molecules.