The Synthesis of two Alkyl-Solubilized [11]phenacenes

Posted July 13th, 2011 at 7:44 pm.

Abstract: Kim Mullane

Mentor: Frank Mallory

[n]Phenacenes are molecules containing n aromatic rings joined together in a zigzag pattern. Since they can be thought of as graphene ribbons, which have conductive properties, they should have the potential to be used as molecular wires. The solubility of unsubstituted [n]phenacenes decreases dramatically with increasing n; [7]phenacene was found by the Mallory group to have negligible solubility. Currently the longest known [n]phenacene is an [11]phenacene derivative that was synthesized by the Mallory group with tert-butyl substituents acting as solubilizing groups, but it was found to have only modest solubility.  The goal of my research is the synthesis of the [11]phenacene derivatives shown below. My previous attempted synthesis of an [11] phenacene with two long-chain alkyl groups proved difficult in the last step of the synthesis due to solubility issues.  In the anticipation that four long-chain alkyl groups would increase the solubility, the synthesis of the [11] phenacene with four solubilizing groups was initiated.  Unfortunately, the second to last reaction in its synthesis did not seem to be successful for unknown reasons; however, the department has now acquired a UV detector for the LCMS that should allow verification of the precursor of the [11]phenacene derivative with a hydrogen in the place of R2, and a technique for tracking the last reaction in a way that is more precise than NMR spectroscopy.  The purpose of my research this summer is to synthesize the precursors to the [11] phenacene derivatives shown below and verify their identity using the LCMS and from there, attempt the photocyclization reactions to give the [11] phenacene derivatives themselves.

kmullane1

kmullane2


The planned syntheses of these compounds involve a sequence of different types of chemical reactions, including Grignard, Friedel-Crafts, bromination, Arbuzov, Horner-Wadsworth-Emmons, and photocyclization reactions

Filed under: 2011,Mallory, Dr. Frank,Mullane, Kim by Michelle Han

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