Building Blocks: Synthesis of [n]Phenacenes

Posted June 25th, 2010 at 10:45 am.

Abstract: Alexandra Ashley
Mentor: Dr. Mallory
[n]Phenacenes are large polycyclic aromatic compounds that are composed of [n] amount of benzene rings fused together. The fused rings form a zigzag pattern which resembles graphite ribbons. One example of a [n]phenacene (with no solubilizing groups attached) is the [5]phenacene shown below.

A special characteristic of these molecules is in their ability to conduct electricity and act as “molecular wires”. This is possible due to the overlapping pi systems of the aromatic rings. The large molecules are built up piece-wise, the largest of which that has been synthesized to date contained 11 fused benzene rings. The synthesis of [15]phenacene and [19]phenacene are two of the current projects in the Mallory research laboratory. One difficulty with forming these large molecules is that they are highly insoluble. Due to this quality of the [n]phenacenes, much research has gone into investigating the nature of different solubilizing groups.

One of the goals of this research is to make large amounts of the starting materials, 7 and 9, which can go on to make [11]phenacene and [15]phenacene. Both of these compounds, as shown below are three ringed phenacenes with different solubilizing and reactive groups attached. 7 is produced by a photocyclization technique and 9 is produced though a phosphonate ester reaction.

Filed under: 2010,Ashley, Alexandra,Mallory, Dr. Frank Tags: by Lisa Klinman

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