Dibenzothiophenes polymers

N. Nemoto, H. Kameshima, Y. Okano, and T. Endo, Synthesis of novel ir-conjugating polymers based on dibenzothiophene, J. Polym. Sci., Part A Polym. Chem., 41 1521-1526, 2003. 

Diphenylsulfone was not detected in the pyrolysate, either because it is not formed at detectable levels, or because it may not elute from the Carbowax column used for the separation of the pyrolysate. However, this compound and other sulfur-containing compounds may be formed during pyrolysis and not detected in the analysis step. The SO2 group represents 27.58% of the weight of the polymer, and only 19.94% molecular SO2 is detected in the pyrogram (assuming equal detector response for all analytes). The other sulfur-containing compounds except for diphenylsulfide (0.33%) and dibenzothiophene (0.72%) are at a trace levels. The thermal decomposition of PES takes place, very likely, by a radicalic mechanism, and the free radicals can interact and form other stable molecules such as biphenyl ( 4 % of volatile pyrolysate), 4-hydroxybiphenyl ( 2% of volatile pyrolysate) and dibenzofuran ( 12% of volatile pyrolysate) which are shown below ... 

Poly(dibenzosilole)s are a relatively new class of compounds for the area of organic electronic materials. Poly(dibenzosilole)s are not easily oxidised and have advantages of solubility and processibility over other polyfluorene analogues, such as carbazoles, dibenzophosphole oxides and dibenzothiophene dioxides. Several groups have already incorporated poly(dibenzosilole)s in the latest organic electronic devices such as OLEDs, OFETs and OSCs and have found improved performance over similar polyfluorene-based devices. With continual advancement in their synthesis, dibenzosilole-based polymers are set to match the popularity of polyfluorenes in organic electronic materials. 

Several random fluorene-dibenzothiophene copolymers 67a-e [106,107] have been reported. The meta linkage in the dibenzothiophene in copolymers 67a-e hinders the conjugation, resulting in a hypsochromic shift of the emission bands to the deep-blue color region (kmax 420 and 440 nm) [106]. Furthermore, hindered conjugation and hindered n-aggregation suppress the parasitic green emission at 520 nm in the solid state of the polymer, often observed in polyfluorenes. 

S. M. King, I. I. Perepichka, I. F. Perepichka, F. B. Dias, M. R. Bryce, A. P. Monkman, Exploiting a dual fluorescence process in fluorene-dibenzothiophene-5,5-dioxide co-polymers to give efficient single polymer LEDs with broadened emission, Adv. Funct. Mater., 19, 586-591 (2009). 

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