Stabilizer, rubrene

By media variables we mean the solvent, electrolyte, and electrodes employed in electrochemical generation of excited states. The roles which these play in the emissive process have not been sufficiently investigated. The combination of A vV-dimethylformamide, or acetonitrile, tetra-n-butylammonium perchlorate and platinum have been most commonly reported because they have been found empirically to function well. Despite various inadequacies of these systems, however, relatively little has been done to find and develop improved conditions under which emission could be seen and studied. Electrochemiluminescence emission has also been observed in dimethyl sulfite, propylene carbonate, 1,2-dimethoxyethane, trimethylacetonitrile, and benzonitrile.17 Recently the last of these has proven very useful for stabilizing the rubrene cation radical.65,66 Other electrolytes that have been tried are tetraethylam-monium bromide and perchlorate1 and tetra-n-butylammonium bromide and iodide.5 Emission has also been observed with gold,4 mercury,5 and transparent tin oxide electrodes,9 but few studies have yet been made1 as to the effects of electrode construction and orientation on the emission character. 

Aromatic hydrocarbons, with the reaction scheme as described above, play the same key role in ECL studies as in organic electrochemistry and organic UV-VIS spectroscopy. 5,6,11,12-Tetraphenyltetracene (rubrene) and 9,10-diphenylanthracene (DPA) are the most notable examples (Fig. 10). The stability of their radical ions, with the quantum efficiency of the parent molecules near unity, [121] has fascinated many ECL investigators since the 1960s ([122,123] and cited references). Taking into account the fact that other aromatic hydrocarbons usually do not form stable... 

Later the same authors61 published a study on the reactivities of a number of electrogenerated radical cations toward St and isobutyl vinyl ether (IBVE). The reactivity comparison was made among 9-phenylanthracene (9PA), 9,10-dimethyl-anthracene (DMA), 9,10-diphenylanthracene (DPA), 1,3,6,8-tetraphenylpyrene (TPP), rubrene (RU), triphenylene (TP), perylene (p). The stability of the ion radicals, in the absence of the monomers, is in the order ... 

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