L-nipecotic acid-porphyrin derivative: a chiral host with introverted functionality for chiral recognition.

The synthesis and chiral recognition properties of a porphyrin host with introverted functionality is reported. The host is a hybrid of tetraphenyl zinc porphyrin and the N-phenylamide derivative of (S)-nipecotic acid. The chiral recognition properties of the porphyrin host with chiral carboxylate-containing guests is described. UV/vis and (1)H NMR spectroscopic results indicate the host shows enantioselectivity for (S)-mandelate tetrabutyl ammonium salt.

Enhanced shape-selective recognition of anion guests through complexation-induced organization of porphyrin hosts.

We present a fortuitous discovery of enhanced shape-selective recognition of anion guests that stems from a complexation-induced conformational change in porphyrin hosts upon anion binding. Porphyrin hosts reported here exist in a conformation that is not favorable to guest binding. Anions that bind strongly are those that can induce a conformational change in the host to allow guest binding. Furthermore, guests that mimic the shape of the newly formed pocket bind the strongest.