Porphyrins functionalized at one meso position with one, two or three hydrogen bond donating groups have been prepared as receptors for anions that vary in geometry and numbers of coordinating sites. In this work, we report the anion recognition properties of eight first-generation 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). These hosts show enhanced-binding of guests that best match the shape of the binding pocket. The hosts exhibit a complexation-induced conformational change in porphyrin hosts upon anion binding. UV/Vis, 1H-NMR and computational studies of guest recognition will be reported. Second generation hosts have been prepared that have anion hydrogen bonding groups positioned to better complement the shape and size of target anion guests. Preliminary results for the anion recognition properties of second-generation hosts will also be reported.

Porphyrin-based hosts that complement the shape of the target guest show enhanced selectivity in anion recognition: A UV/Vis, NMR and computational study

247th National Meeting (2014)

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