Synthesis and Study of Enhanced Shape Selective Anion Hosts

Document Type


Degree Name

Master of Science (MS)



Date of Award

Fall 2012


The aim of this project is to develop shape selective anion receptors with the idea that one can consider an anion's geometry, basicity, electron density distribution, and charge before designing a receptor to mimic these properties. The porphyrin hosts reported here bind anions through cooperative metal coordination and hydrogen bond interactions. We report here the synthesis of eight porphyrin hosts and their recognition properties with ten anion guests that vary in geometry: spherical (chloride, bromide, and iodide), bent (acetate, nitrite), trigonal planar (nitrate, carbonate), tetrahedral (perchlorate, perrhenate, hydrogen sulfate, and dihydrogen phosphate). The porphyrin hosts are functionalized at one meso- position with one, two, or three anion binding sites that work in tune with the porphyrin metal center to create a binding pocket for bent, trigonal planar or tetrahedral anions. Thus, a key aspect of the work centers on the design of the receptors with anion recognition elements that are pre-positioned to mimic the geometry of the anion target. We anticipate selectivity in guest binding stems from a complexation-induced conformational change in porphyrin hosts upon anion binding.


Stephen Starnes

Subject Categories

Chemistry | Physical Sciences and Mathematics