Highly fluorinated metal complexes as dual ¹⁹F and PARACEST imaging agents

Abstract

Highly fluorinated, water-soluble transition metal complexes serve as both 19F and PARACEST magnetic resonance imaging agents.

19F MRI Probes for Multimodal Imaging**

“…A wide range of cyclen [20,88–90] and cyclam‐based [87] ligands was reported with varying number of fluorine atoms (3–18) and exchangeable protons (1–7). A significant issue is the solubility of the complexes in aqueous environment.…”

“…A detailed discussion of the impact of structural features on NMR properties of cyclen-derived lanthanide complexes and possible applications as 19 F/CEST agents was presented by Pujales-Paradela et al The study implies that careful selection of the metal type and the distance between the metal and fluorine atoms is crucial for sensitivity. [90] A wide range of cyclen [20,[88][89][90] and cyclam-based [87] ligands was reported with varying number of fluorine atoms (3-18) and exchangeable protons (1-7). A significant issue is the solubility of the complexes in aqueous environment.…”

“…Paramagnetic complexes for 19 F and PARACEST imaging proposed by Yu et al Reproduced with permission. [88] Copyright 2019, The Royal Society of Chemistry.…”

Paramagnetic Cobalt(II) Complexes with Cyclam Derivatives: Toward 19F MRI Contrast Agents

“…higher CA efficiency) than those previously published for nickel(II) complexes where T2 * /T1 ratios ranged from 0.32 to 0.48. 25,26 They are, however, lower than those reported for a number of other macrocyclic complexes with f and d-transition ions, including a Dy(III) complex of a DOTA-diamide derivative with two -CF3 groups (T2 * /T1 = 0.96; 4.7 T, 295 K), 50 Fe II /Co II /Ni II complexes of a DOTA-tetramide derivative with six -CF3 groups (T2 * /T1 ~ 0.9; 9.4 T, 296 K), 22 or a Ni(II) complex of cross-bridged cyclam derivatives with one/two -CF3 groups (T2 * /T1 ~0.8; 7.1 T, 298 K). 28 Nevertheless, the T2 * /T1 ratios of the present cobalt(II) complexes are significantly higher than those in M-DOTA-AmF12 complexes with the T2 * /T1 values 0.07-0.18 and 0.57 (7 T, 298 K) for M = Ln 3+ and Fe 2+ , respectively.…”

“…[25][26][27][28] The transition metal containing 19 F-MRI contrast agents have been used as responsive probes. 18,22,29 The mostly utilized metal ions are divalent iron, cobalt or nickel. Chemical, biochemical and magnetic properties of these complexes are often more favourable than those of more commonly utilized complexes of trivalent lanthanides.…”