Preparation and Characterization of New Amino-Substituted Crowns and Podands

A number of macrocyclic (1b-3b) and linear oligoether compounds (4b-8b) with 2,2′-methylenebis(4-aminophenol) or 2-aminophenol characteristic building blocks have been synthesized by reduction of the corresponding nitro derivatives with Pd-C/hydrazine hydrate. The pKa′ values of the new compounds have been determined by potentiometric titration. These and the observed spectroscopic data are discussed and compared with related compounds. A crystalline 1:1 complex of the diamino crown 3b with NaSCN has also been prepared and characterized.