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Crystallographic Characterization and Non‐Innocent Redox Activity of the Glycine Modified DOTA Scaffold and Its Impact on Eu III Electrochemistry
Author(s) -
Burnett Marianne E.,
Adebesin Bukola,
Ratnakar S. James,
Green Kayla N.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201701398
Subject(s) - dota , chemistry , electrochemistry , europium , gadolinium , cyclic voltammetry , ligand (biochemistry) , redox , glassy carbon , crystallography , electrocatalyst , electrode , combinatorial chemistry , inorganic chemistry , ion , chelation , organic chemistry , receptor , biochemistry
EuDOTA‐glycine derivatives have been explored as alternatives to typical gadolinium‐containing complexes for MRI agents used in diagnostic imaging. Different imaging modalities can be accessed ( T 1 or PARACEST) dependent on the oxidation state of the europium ion. Throughout the past 30 years, there have been significant manipulations and additions made to the DOTA scaffold; yet, characterizations related to electrochemistry and structure determined through XRD analysis have not been fully analyzed. In this work, electrochemical analysis using cyclic voltammetry was carried out on EuDOTA derivatives, including the free ligand DOTAGly 4 ( 4 ) and the complexes. Effects of glycinate substitution on the DOTA scaffold, specifically, ligand interactions with the glassy carbon electrode were observed. A range of electrochemical investigations were carried out to show that increased glycinate substitution led to increased interaction with the electrode surface, thus implicating a new factor to consider when evaluating the electrochemistry of glycinate substituted ligands. In addition, the solid‐state structure of EuDOTAGly 4 ( Eu4 ) was determined by X‐ray diffraction and a brief analysis is presented compared to known Ln 3+ structures found within literature. The Eu4 complex crystalizes in a rare polymer type arrangement via bridging side‐arms between adjacent complexes.