Structural Studies of Porphyrin Hosts for Anion Guests and Second Generation Receptors

Document Type


Degree Name

Master of Science (MS)



Date of Award

Summer 2014


In this work, we report the anion recognition properties of eight porphyrin-based hosts for eleven anion guests that vary in geometry: spherical (chloride, bromide, and iodide), `bent' (acetate, nitrite), trigonal planar (nitrate, carbonate), and tetrahedral (perchlorate, perrhenate, hydrogen sulfate, and dihydrogen phosphate). A key aspect of the work centers on the design of the receptors with anion recognition elements that are pre-positioned to mimic the bent, trigonal planar or tetrahedral geometry of the anion target. Hosts show enhanced-binding of guests that best match the shape of the binding pocket. Enhanced-selectivity in guest binding stems from a complexation-induced conformational change in porphyrin hosts upon anion binding to give porphyrin hosts with binding pockets for anions which match the anion guest's geometry. Binding constants for anion guests were determined through UV/Vis titration studies. Preliminary results for the synthesis and anion recognition properties of hosts that have been modified from the initial design in order to improve on the selective binding of trigonal planar anions also reported.


stephen starnes

Subject Categories

Chemistry | Physical Sciences and Mathematics