9,10-Dicyanoanthracene electron-accepting sensitizer

Transition metal complexes like PdCl2( " -NBD) and [Ru(bpy)3] or 9,10-dicyanoanthracene and 1,2,4,5-tetracyanobenzene have been successfully used as electron-accepting sensitizers. Reductive quenching of the excited singlet state of the electron acceptor (A ) by Q leads to the formation of its radical cation Qwhich... 

A different mechanism operates upon electron-transfer-sensitized photooxygenation, generally carried out by using electron-accepting sensitizers such as 9,10-dicyanoanthracene, triphenylpyrylium salts, and others. ° " The arylalkene radical cation 14 is formed and then reacts either with the superoxide anion or, more likely, with oxygen. Kinetic factors are also important " ... 

According to the second scenario, an auxiliary electron acceptor, for example 9,10-dicyanoanthracene (DC A) in the excited state, is used as a co-sensitizer.670 DC A absorbs well in the near-UV region and, in the excited singlet state (Es = 284 kJ mol 1), it can accept an electron from A-methyl-A-(trimethylsilylmethyl)aniline (423) to give an amine radical cation 424 (Scheme 6.202). This intermediate subsequently attacks... 

Behavior of olefin radical cations has not been vjell investigated until recently. Lewis reported that 9,10-dicyanoanthracene (DCA) sensitized irradiation of stilbene led to its cis to trans isomerization (33). The resulting c - from electron transfer from cis-isomer to DCA isomerizes to t , v hich subsequently accepts an electron from cis to give trans and regenerate leading to a chain process. The quantum yield for cis to trans isomerization increases with increasing cis-isomer concentration. 

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