A Nuclear Singlet Lifetime of More than One Hour in Room-Temperature Solution

• Published in: Angewandte Chemie International Edition Vol. 54; no. 12; pp. 3740 - 3743
• Main Authors: Stevanato, Gabriele, Hill-Cousins, Joseph T., Håkansson, Pär, Roy, Soumya Singha, Brown, Lynda J., Brown, Richard C. D., Pileio, Giuseppe, Levitt, Malcolm H.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 16-03-2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Communications; Decay; Dynamical systems; long-lived spin states; Magnetic resonance imaging; Magnetization; NMR; NMR spectroscopy; Nuclear magnetic resonance; nuclear spin relaxation; Nuclei; Quantum chemistry; singlet states; Time constant; long-lived spin states; NMR spectroscopy; nuclear spin relaxation; singlet states
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201411978

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are supremely important techniques with numerous applications in almost all branches of science. However, until recently, NMR methodology was limited by the time constant T1 for the decay of nuclear spin magnetization through contact with the thermal molecular environment. Long‐lived states, which are correlated quantum states of multiple nuclei, have decay time constants that may exceed T1 by large factors. Here we demonstrate a nuclear long‐lived state comprising two 13C nuclei with a lifetime exceeding one hour in room‐temperature solution, which is around 50 times longer than T1. This behavior is well‐predicted by a combination of quantum theory, molecular dynamics, and quantum chemistry. Such ultra‐long‐lived states are expected to be useful for the transport and application of nuclear hyperpolarization, which leads to NMR and MRI signals enhanced by up to five orders of magnitude.
A long‐lived nuclear singlet: A molecular system based on a 13C2‐labelled naphthalene core has been designed to support long‐lived nuclear singlet order in solution. A nuclear singlet lifetime exceeding one hour has been achieved in room‐temperature solution.