Quaterthiophenes

K. Chondroudis and D.B. Mitzi, Electroluminescence from an organic-inorganic pereovskite incorporating a quaterthiophene dye within lead halide perovskite layer, Chem. Mater., 11 3028-3030,1999. 

Similar results have been obtained with 4T (quaterthiophene) in dichloromethane (absorption maximum at 390 nm). The observed transient spectrum appears structured with two maxima at 560 nm and 610 nm. The lifetime of the corresponding triplet 34T is on the order of 35 (is. The excitation of 6T in dichloromethane (absorption maximum at 432 nm) leads to a transient triplet with an absorption maximum at 680 nm and a lifetime of about 24 (is. 

The synthesis and OFET properties of new carbonyl-functionalized quaterthiophenes 480-484 exhibiting improved stability and unique charge transport characteristics were reported (04JA13859 05JA1348). 

Oligothiophene derivatives can also be inserted in a polyester matrix. A quaterthiophene derivative-polyester showed an absorption band at 407 nm and fluorescence emissions at 482 and 507 nm (4>F = 0.17 tf 0.41 ns) (98MM6289). 

The solvent-free, microwave-assisted coupling of thienyl boronic acids and esters with thienyl bromides, using aluminum oxide as the solid support, served to rapidly check the reaction trends on changing times, temperature, catalyst, and base and easily optimize the experimental conditions to obtain the desired product in fair amounts. This procedure offers a novel, general, and very rapid route to the preparation of soluble thiophene oligomers. Quaterthiophene 265 was obtained in 6 min by reaction of 2-bromo-2,2 -bithiophene with bis(pinacolato)diborane(4) in 65% yield, whereas dithiophene 266 was obtained with 70% yield. The synthesis of new chiral 2,2 -bithiophenes also was reported. The detailed... 

Fig. 2.5. Transmission difference spectra AT/T of quaterthiophene in solution. Photobleaching (PB) is seen as a rise towards the low wavelength edge and develops outside the experimentally accessible spectral range. Stimulated emission (SE) and photoinduced absorption (PA) from Si are seen at 500 nm and 675 nm, respectively. They decay in about 600 ps and a new PA band appears, at 560 nm, assigned to triplet-triplet transitions. A clear isosbestic point occurs at 600 nm. The data are an example of intersystem crossing in photoexcited molecules induced by spin-orbit wavefunction mixing...

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