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Updated: Mar 6, 2026

Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging
Published on: December 30, 2016
Bis-Gadolinium Complexes for Solid Effect and Cross Effect Dynamic Nuclear Polarization
Monu Kaushik1, Mian Qi2, Adelheid Godt2
1Goethe-Universität Frankfurt am Main, Institut für Physikalische und Theoretische Chemie, Institut für Biophysikalische Chemie und Biomolekulares Magnetresonanzzentrum (BMRZ), Max-von-Laue-Strasse 7-9, 60438, Frankfurt am Main, Germany.
Abstract:
High-spin complexes act as polarizing agents (PAs) for dynamic nuclear polarization (DNP) in solid-state NMR spectroscopy and feature promising aspects towards biomolecular DNP. We present a study on bis(Gd-chelate)s which enable cross effect (CE) DNP owing to spatial confinement of two dipolar-coupled electron spins. Their well-defined Gd⋅⋅⋅Gd distances in the range of 1.2-3.4 nm allowed us to elucidate the Gd⋅⋅⋅Gd distance dependence of the DNP mechanism and NMR signal enhancement. We found that Gd⋅⋅⋅Gd distances above 2.1 nm result in solid effect DNP while distances between 1.2 and 2.1 nm enable CE for 1 H, 13 C, and 15 N nuclear spins. We compare 263 GHz electron paramagnetic resonance (EPR) spectra with the obtained DNP field profiles and discuss possible CE matching conditions within the high-spin system and the influence of dipolar broadening of the EPR signal. Our findings foster the understanding of the CE mechanism and the design of high-spin PAs for specific applications of DNP.
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