| Autor: |
Appleby KM; Centre for Hyperpolarization in Magnetic Resonance , University of York , York Science Park , York , YO10 5NY , UK . Email: simon.duckett@york.ac.uk.; Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK., Mewis RE; Centre for Hyperpolarization in Magnetic Resonance , University of York , York Science Park , York , YO10 5NY , UK . Email: simon.duckett@york.ac.uk.; Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK., Olaru AM; Centre for Hyperpolarization in Magnetic Resonance , University of York , York Science Park , York , YO10 5NY , UK . Email: simon.duckett@york.ac.uk.; Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK., Green GGR; Centre for Hyperpolarization in Magnetic Resonance , University of York , York Science Park , York , YO10 5NY , UK . Email: simon.duckett@york.ac.uk.; Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK., Fairlamb IJS; Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK., Duckett SB; Centre for Hyperpolarization in Magnetic Resonance , University of York , York Science Park , York , YO10 5NY , UK . Email: simon.duckett@york.ac.uk.; Department of Chemistry , University of York , Heslington , York , YO10 5DD , UK. |
| Abstrakt: |
The reaction of [Ir(IMes)(COD)Cl], [IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, COD = 1,5-cyclooctadiene] with pyridazine (pdz) and phthalazine (phth) results in the formation of [Ir(COD)(IMes)(pdz)]Cl and [Ir(COD)(IMes)(phth)]Cl. These two complexes are shown by nuclear magnetic resonance (NMR) studies to undergo a haptotropic shift which interchanges pairs of protons within the bound ligands. When these complexes are exposed to hydrogen, they react to form [Ir(H) 2 (COD)(IMes)(pdz)]Cl and [Ir(H) 2 (COD)(IMes)(phth)]Cl, respectively, which ultimately convert to [Ir(H) 2 (IMes)(pdz) 3 ]Cl and [Ir(H) 2 (IMes)(phth) 3 ]Cl, as the COD is hydrogenated to form cyclooctane. These two dihydride complexes are shown, by NMR, to undergo both full N-heterocycle dissociation and a haptotropic shift, the rates of which are affected by both steric interactions and free ligand p K a values. The use of these complexes as catalysts in the transfer of polarisation from para -hydrogen to pyridazine and phthalazine via signal amplification by reversible exchange (SABRE) is explored. The possible future use of drugs which contain pyridazine and phthalazine motifs as in vivo or clinical magnetic resonance imaging probes is demonstrated; a range of NMR and phantom-based MRI measurements are reported. |
