A Sm(II)-mediated cascade approach to dibenzoindolo[3,2-b]carbazoles: synthesis and evaluation.

Previously unstudied dibenzoindolo[3,2-b]carbazoles have been prepared by two-directional, phase tag-assisted synthesis utilizing a connective-Pummerer cyclization and a SmI2-mediated tag cleavage-cyclization cascade. The use of a phase tag allows us to exploit unstable intermediates that would otherwise need to be avoided. The novel materials were characterized by X-ray, cyclic voltammetry, UV-vis spectroscopy, TGA, and DSC. Preliminary studies on the performance of OFET devices are also described.

BPTs: thiophene-flanked benzodipyrrolidone conjugated polymers for ambipolar organic transistors.

A series of novel thiophene-flanked benzodipyrrolidone (BPT)-based alternating copolymers are synthesised, their optical and electrical properties evaluated. The BPT unit promotes a conjugated, planar polymer backbone, with a low bandgap, primarily due to low lying LUMO energy levels. Copolymerisation with thiophene exhibits well balanced ambipolar organic field-effect transistor performance, with electron and hole mobilities 0.1 and 0.2 cm(2) V(-1) s(-1), respectively.

Phase tag-assisted synthesis of benzo[b]carbazole end-capped oligothiophenes.

The introduction and removal of a phase tag have been used to trigger cyclization events in a new synthesis of benzo[b]carbazoles. The approach has been exploited in a tag-assisted approach to new benzo[b]carbazole end-capped oligothiophenes for preliminary evaluation as semiconductors.