P-Containing Heteroarenes Synthesis, Properties, Applications

In the context of heteroarenes, five-membered rings containing phosphorus occur in many forms. The most common species is phosphole, the analog to pyrrole and thiophene, which contains a butadiene fragment bridged with a phosphorus functional group. Because of the pyramidal geometry of the phosphorus center. 

Polycyclic Arenes and Heteroarenes Synthesis, Properties, and Applications, First Edition. Edited by Qian Miao. 2016 Wiley-VCH Verlag GmbH Co. KGaA. Published 2016 by Wiley-VCH Verlag GmbH Co. KGaA. 

When lithiation or metalation of the starting materials is not a viable choice for synthesis, radical phosphanylation is another alternative synthetic option [7]. This method is typically used when metalation of multiple sites is difficult to achieve it involves the use of a stannylated phosphorus species and a halogenated 

As shown by the DFT calculations, the lowering of the LUMO also leads to a decrease in the reduction threshold. It should also be noted that a more red-shifted absorption and emission would likely entail a lowered reduction potential, as described by the molecular orbital properties. This is, in fact, observed experimentally with the reduction potentials for 2a-c, which have reduction potentials 

11a E = lone pair 11aE = 0 11cE = S 11dE = SMe 11eE = Me  

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