Synthesis and Characterization of Cross-Conjugated Macrocycles and Exploratory Study of their Organometallic Chemistry

• Author / Creator

  Gholami, Mojtaba

• This thesis covers the synthesis, characterization and physical studies of cross-conjugated macrocycles, expanded radialenes, as well as their related derivatives. The main synthetic protocol that is used throughout this thesis is based on the Pd-mediated Sonogashira cross coupling reaction of a desilylated iso-polydiacetylene with a dibromoolefin. To initiate the synthesis, a series of [3]–, [4]–, and [5]expanded radialenes was synthesized, characterized, and studied by UV-vis spectroscopy, electrochemistry, and solid-state analysis. The results confirm the macrocycles are achievable in reasonable yields and suitable for further physical studies without any concerns for their stability in the solid or solution phase. At the same time, the use of tetrabromoethene in analogous Sonogashira cross coupling reactions afforded bisexpanded radialenes and radiaannulenes that exhibited interesting physical properties according to UV-vis spectroscopy and cyclic voltammetric analysis. This thesis also covers some interesting results, in particular, for [3]expanded radialenes that undergo cycloaddition reactions. As well, physical studies of the target radialenes show that as the macrocycles become more strained, they exhibit more unique and unexpected electronic and optical properties. Having the first series of the radialenes in hand, the synthetic plan shifted towards the synthesis of functional expanded radialenes, which were produced in good to very good yields. In particular, the existence of a [4]expanded radialene carrying triisopropylsilylethynyl groups as exocyclic substituents provided an opportunity for derivatization of the expanded radialene framework. The general protocol for radialene synthesis was also applied using tetrabromides of anthracenylidene and pentacenylidene in Sonogashira reactions. These efforts afforded structurally unique bisexpanded radialene and radiaannulene products. Because of their shape and structure, radialenes have potential for use in organometallic chemistry or as ligands in inorganic chemistry. Exploratory studies have been focused on [3]– and [4]expanded radialenes. By all accounts, [3]radialenes reacted more easily with selected precursors such Pt(PPh3)4 and Co2(CO)8. Throughout this thesis, all the major radialene frameworks are established in terms of solid-state structures by X-ray crystallography. Finally, electrochemical analyses show that the new series radialenes reported in this work are generally reduced at higher potentials when compared to the previous generation of expanded radialenes based on butadiynyl building blocks.

• Subjects / Keywords

  • Cross-Conjugated

• Graduation date

  Fall 2009

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3F08X

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.