Levitt, Malcolm H. “Long Live the Singlet State!” Journal of Magnetic Resonance 306 (September 2019): 69–74.
The ﬁeld of long-lived states in NMR is reviewed. The relationship of long-lived-state phenomena to those associated with spin isomerism is discussed. A brief overview is given of key developments in the ﬁeld of long-lived states, including chemical symmetry-switching, the role of magnetic equivalence and magnetic inequivalence, long-lived coherences, hyperpolarized NMR involving long-lived states, quantumrotor-induced polarization, and parahydrogen-induced hyperpolarization. Current application areas of long-lived states are reviewed, and a peer into the crystal ball reveals future developments in the ﬁeld. Ó 2019 Published by Elsevier Inc.