Synthesis and properties of poly(3,9-carbazole) and low-molar-mass glass-forming carbazole compounds

The novel π-conjugated polymer poly(3,9-carbazole) was prepared by Ullmann polycondensation reaction of 3-iodo-9H-carbazole. The polymer has a number-average molecular weight of ca. 2400 with a molecular weight distribution of 2.15. The dimer model compound and the carbazole trimer 3,6-di(carbazolyl)alkylcarbazole have been synthesized by stepwise reactions. All these compounds have been found to form glasses with glass transition temperatures in the range 35–157 °C as characterized by differential scanning calorimetry. The ionization potentials of these compounds range from 5.45 to 5.97 as determined by the electron photoemission method. Time of flight experiment showed that hole drift mobilities of the low-molar-mass glasses were in the range 10−5–10−3 cm2 V−1 s−1.