Chapter 4. Design and Synthesis of Molecules Supporting Long-lived Spin Order

Advances in research in the field of extended nuclear singlet lifetimes have been made possible by effective collaboration between synthetic chemists and NMR specialists. The synthesis of different classes of isotopically labelled molecules that have been shown to support long-lived singlet states from minutes to over one hour is described. These molecules have been designed according to criteria developed to provide access to the singlet state whilst attenuating the rate of relaxation. Utilising synthetic routes optimised using relatively less costly unlabelled analogues, the challenges of specific incorporation of stable isotopes in precise positions and in high yields have been overcome.