Date of Award
Doctor of Philosophy
Alan W. Schwabacher
Metal complexes of the amino acid, 4,4[superscript]'-phosphinylidine bis phenylalanine (PBP*, 1), self-assemble to produce a macrocyclic receptor (Co[subscript]2PBP[subscript]2, 2) with a hydrophobic cavity capable of binding aromatic compounds from water. Here we demonstrate that the metal can play a structural and a functional role: the receptor binds substrates bearing both aromatic and polar functional groups ditopically, using the hydrophobic pocket as well as the metal itself. The doubly anionic Co[superscript]2+ macrocyclic complex binds neutral aromatic guests more tightly than it does most anionic guests, as would be expected. However, carboxylates tethered such that ligation of the metal is possible cause enhanced binding. NMR studies of these paramagnetic materials support ditopic binding, and reveal very large complexation induced shifts in both the host and the guest. Co[superscript]2+ macrocyclic complex demonstrates 9 fold enantioselectivity in substrates binding through ditopic binding. ftn*Please refer to dissertation for diagram.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Lee, Jin-ho, "Cooperative binding by a self-assembled receptor: metal in a structural and functional role " (1994). Retrospective Theses and Dissertations. 10493.