Characterization of Co(II)-PAMAM dendrimer complexes with polypropylene oxide core by using UV-VIS spectroscopy

Abstract

The aim of this study was to characterize poly(amidoamine) (PAMAM) dendrimer complexes of Co(II) ions by using UV-Vis spectroscopy. For this aim, a generation-4 polypropylene oxide (Jeffamine® T-403) cored and amine-terminated PAMAM dendrimer (P4) was used as a model complexation agent. Optimum complexation condition for P4 was determined by potentiometric and spectroscopic titration studies. Extent of protonation (EOP) of the amino groups of P4 was determined from the potentiometric titration data and validated with spectroscopic titration data. The results indicated that pH 8 was the optimum dendrimer aqueous solution media, where the available number of tertiary amines present in P4 was the highest for possible metal complexation. At the optimized conditions, UV-Vis characterization of the Co(II)-P4 complexes was performed and 585–635 nm d-d transition bands were observed as the characteristic complexation bands of the tertiary amine groups of P4 with Co(II) ions. Obtained Co(II)-P4 complexes might be considered for the development of magnetic resonance image (MRI) improvers or MRI contrast agents.

Keywords

• pamam dendrimer
• jeffamine
• complexation
• uv-vis spectroscopy
• mri contrast agents