Coupling of diethylenetriamine to carboxyl-terminated magnetic particles

The ligand diethylenetriamine (DETA) has been successfully coupled to carboxy-terminated magnetic particles, using the carbodiimide EDCI. Amine related peaks from DETA are seen in infrared measurements. The reaction with DETA involves a rearrangement of the self-assembled molecules of dibenzoic acid diamide bolaamphiphile, DBSC-10, on the maghemite, as seen from a shift of methylene peaks, indicating less mobile hydrocarbon chains. XPS measurements and a deconvolution of peaks indicate that one out of two molecules of DBSC-10 is reacting with DETA to form new amide linkages. This gave an amount of DETA-reacted DBSC-10 molecules on the surface of 84 μmol g−1 of carboxy-terminated particles. Titration of the DETA-reacted particles show the titration of two different types of protons, amine and carboxylic, in the ratio of 1:1. Finally, the amount of base required for the complete titration of DETA-reacted particles (0.5 ml per 25 mg of titrated particles) excludes the possible cross-linking reaction of DETA with free carboxylic groups from DBSC-10.