Synthesis of neutral anion receptor 5,10-bis-(2-(4-fluorophenyl)phenylurea)-15,20-diphenylporphyrin and its characterization
Binding studies were performed with a bisurea-picket porphyrin host receptor (a,a)-5,10- Bis-(2-(4-fuorophenyl)phenylurea)-15,20-diphenylporphyrin (1a) and TBA salts as its guest. Previously our group reported1 on the binding studies of tetrakis-urea-picket porphyrin (a,a,a,a)-5,10,15,20-tetrakis-(2-(4-fuorophenyl)phenylurea)porphyrin (3) and tris-urea-picket porphyrin (a,a,a)-5,10,15-tri(2-(4-fuorophenyl)phenylurea)-20-phenylporphyrin (2) using polar solvent, DMSO, where a strong binding preference was observed for Cl¯ anion over H2PO4 ¯, CH3CO2 ¯, and NO3 ¯. A crystal structure (Figure 1- 1, Chapter 1) of the tetrakisurea-picket porphyrin 3 - chloride anion complex showed the anion bound between two adjacent ureas and hydrogen bonded to the four NH protons. It also showed the presence of one DMSO molecule bound to a third urea. Previously it was hypothesized that the ubiquitous DMSO solvent molecule bound to the third urea arm of the receptor was facilitating the anion binding by coordination utilizing columbic force. Through the investigation described in this thesis it was confirmed that the system of tetrakis- and trisurea-picket porphyrin exhibit a binding selectivity that is facilitated by the incorporation of a solvent molecule in the binding cavity. This was evident by the reversal of binding constant that was observed for the bisurea-picket porphyrin • anion complexation in contrast to that of tris-urea-picket porphyrin • anion complexation and tetrakis-urea-picket porphyrin • anion complexation.
Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry
Includes bibliographic references (leaves 71-73).