Spin-crossover and high-spin iron(ii) complexes as chemical shift ¹⁹F magnetic resonance thermometers.

ABSTRACT: The potential utility of paramagnetic transition metal complexes as chemical shift ¹⁹F magnetic resonance (MR) thermometers is demonstrated. Further, spin-crossover Fe^II complexes are shown to provide much higher temperature sensitivity than do the high-spin analogues, owing to the variation of spin state with temperature in the former complexes. This approach is illustrated through a series of Fe^II complexes supported by symmetrically and asymmetrically substituted 1,4,7-triazacyclononane ligand scaffolds bearing 3-fluoro-2-picolyl derivatives as pendent groups (L _x ). Variable-temperature magnetic susceptibility measurements, in conjunction with UV-vis and NMR data, show thermally-induced spin-crossover for [Fe(L₁)]²⁺

SUBMITTER: Thorarinsdottir AE 

PROVIDER: S-EPMC5477811 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature