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Nuclear Magnetic Resonance Relaxivities: Investigations of Ultrahigh‐Spin Lanthanide Clusters from 10 MHz to 1.4 GHz |
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| Authors: | Julyana R Machado Dr Amer Baniodeh Prof Dr Annie K Powell Prof Dr Burkhard Luy Dr Steffen Krämer Dr Gisela Guthausen |
| Institution: | 1. Pro2NMR at the Institute ‐for Biological Interfaces, Karlsruhe Institute of Technology, Adenauerring 20b, 76131 Karlsruhe (Germany);2. Institute for Nanotechnology (INT), Karlsruhe Institute of Technology, Engesserstr.15, P.O Box 76021 Karlsruhe (Germany);3. Institute for Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstr. 15, 76131 Karlsruhe (Germany);4. Laboratoire National des Champs Magnétiques Intenses, LNCMI‐CNRS (UPR 3228), UJF, UPS, and INSA, Bo?te Postale 166, 38042 Grenoble Cedex 9 (France) |
| Abstract: | Paramagnetic relaxation enhancement is often explored in magnetic resonance imaging in terms of contrast agents and in biomolecular nuclear magnetic resonance (NMR) spectroscopy for structure determination. New ultrahigh‐spin clusters are investigated with respect to their NMR relaxation properties. As their molecular size and therefore motional correlation times as well as their electronic properties differ significantly from those of conventional contrast agents, questions about a comprehensive characterization arise. The relaxivity was studied by field‐dependent longitudinal and transverse NMR relaxometry of aqueous solutions containing FeIII10DyIII10 ultrahigh‐spin clusters (spin ground state 100/2). The high‐field limit was extended to 32.9 T by using a 24 MW resistive magnet and an ultrahigh‐frequency NMR setup. Interesting relaxation dispersions were observed; the relaxivities increase up to the highest available fields, which indicates a complex interplay of electronic and molecular correlation times. |
| Keywords: | Cooperative cluster compounds lanthanides NMR spectroscopy Single molecule magnet ultrahigh magnetic field |