PARASHIFT probes: the importance of coordination environment on the NMR shifts of lanthanide complexes.

摘要

Paramagnetic lanthanide complexes can be used as chemical shift agents in magnetic resonance imaging. By shifting a reporter group away from the endogenous water and fat signals we can selectively observe complex resonances with zero background. The benefit of the fast relaxation induced' by the paramagnetic lanthanide complexes is a much shorter image/spectral acquisition time. The relative magnitude of the shift and relaxation can be roughly predicted by established methods, namely Bleaney and BRW theories. Recently, there have been reports of complexes that do not follow the spectral behaviour predicted by these theories.1'2 A more precise and inclusive theory that correlates magnetic and ligand field anisotropy is needed. Thus, an in-depth understanding of the solution dynamics, molecular structure, electronic structure and magnetic properties of well-defined series of lanthanide complexes is required.