Design of star-shaped organoiron oligomers with azo chromophores

• Main Author: Ding, Man
• Language: English
• Published: University of British Columbia 2011
• Online Access: http://hdl.handle.net/2429/36649

The synthesis and characterization of novel star-shaped oligomers containing cationic η⁶-chloroarene-η⁵-cyclopentadienyliron(II) complexes functionalized with azo chromophores were described in the thesis. Star-shaped macromolecules and dendrimers are of great interest for their application in light-harvesting systems, drug delivery, catalysis, and solvents. The incorporation of cationic η⁶-chloroarene-η⁵-cyclopentadienyliron moieties can enhance solubility and facilitate nucleophilic aromatic substitution and addition reactions due to the intense electron-withdrawing ability of the iron center. On the other hand, the azo dye chromophore in the oligomers has many applications due to its unique photophysical properties and acid-sensing capabilities. Controlled synthetic methods involving both convergent and divergent approaches were employed to give distinct symmetrical branches that alternate between organoiron complexes and azobenzene moieties. Preparation of these molecules was achieved via metal-mediated nucleophilic aromatic substitutions and Steglich esterifications. These oligomers and their precursors were characterized through nuclear magnetic resonance spectroscopy, infrared spectroscopy, ultraviolet-visible spectroscopy and cyclic voltammetry.