Copper complexes as a source of redox active MRI contrast agents

Abstract

This version is available at https://strathprints.strath.ac.uk/54085/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the AbstractThe study reports an advance in designing copper-based redox sensing MRI contrast agents. Although the data demonstrate that copper(II) complexes are not able to compete with lanthanoids species in terms of contrast, the redox-dependent switch between diamagnetic copper(I) and paramagnetic copper(II) yields a novel redox-sensitive contrast moiety with potential for reversibility.

Molecular Sensors Operating by a Spin‐State Change in Solution: Application to Magnetic Resonance Imaging

“…Ligands containing other pendent arms were later synthesized and the relaxivity of these complexes was studied. [40] As expected from the low total spin of these complexes, their relaxivity is modest, between 0.11 and 0.42 mM À 1 s À 1 . Moreover, the redox potential of these complexes was quite high (> 0.65 V) and they thus couldn't be used to target hypoxic cells or tissue.…”

“…Moreover, the tertiary amines thereby created were more stable toward ligand oxidation which occurred during reduction‐oxidation studies. Ligands containing other pendent arms were later synthesized and the relaxivity of these complexes was studied [40] . As expected from the low total spin of these complexes, their relaxivity is modest, between 0.11 and 0.42 mM −1 s −1 .…”

Metal-based redox-responsive MRI contrast agents

“…75 However, with the advent of better imaging software and higher field strengths, limited relaxivity changes are less prohibitive. Spickett and collaborators 104 ( Figure 23) studied three series of Cu II macrocyclic frameworks (66)(67)(68), obtaining the reduced forms by using ascorbic acid as reductant. They observed considerably low r1 changes (0.11-0.44 mM -1 .s -1 ), the highest was reported for the member of the 67 family with X = -(CH2)2OH.…”

Copper complexes for the promotion of iminopyridine ligands derived from β-alanine and self-aldol additions: relaxivity and cytotoxic properties

“…These complexes display relaxivities higher than those measured for LFB 28 and comparable with those reported for other Cu(II) complexes containing N or O-donor ligands that have complicated structures or are more difficult to obtain. [61][62][63] For instance, Reglinski and Spickett et al reported relaxivities in the range of 0.11-0.42 mM -1 s -1 for N-substituted macrocyclic Cu(II) complexes (9.4 T, 0.1 M NaCl in D2O). As noted in the introduction, Luxol fast blue (LFB), a well-known histological stain, has been tested as an MRI contrast agent, and has a comparatively poorer value of 0.09 mM -1 s -1 (aqueous solution at 4.7 T).…”