Metal-directed synthesis of aminobenzyl polyaza macrecycles: candidates for attachment to polymers and biomolecules

Abstract

Copper(II)-directed condensation between 4,7-diazadecane-1,10-diamine, formaldehyde and 1-nitro-3-(2-nitroethyl)benzene yielded the macrocyclic [10-nitro-10-(3-nitrobenzyl)-1,4,8,1 2-tetraazacyclopentadecane] copper(II) ion. Reduction (Zn,HCl) gave the pendant-arm macrocycle 10-(3-aminobenzyl)-1,4,8,12-tetraazacyclopentadec-10-ylamine as the hydrochloride salt. Condensation reactions with 1-nitro-4-(2-nitroethyl)benzene and 2-phenylnitroethane were also successful. The capacity of the aminobenzyl C-pendant introduced by this facile chemistry for covalent attachment has been examined by attachment of 10-(3-aminobenzyl)-1,4,8,12-tetraazacyclopentadec-10-ylamine to the acidic cation-exchange resin CM Bio-Gel A and to horse heart cytochrome c, employing a water-soluble carbodiimide coupling agent at pH 5 to promote amide formation. The attachment was probed by copper(II) complexation to the bound macrocycle and subsequent spectroscopic or voltammetric analysis.