Preface

It was the beginning of 2005 and I was looking for a research group to spend six months with as a part of my PhD programme. I ended up joining Levitt's group in Southampton with the clear aim to learn about spin dynamics in great depth. That was indeed the right place. At that time Malcolm and group members were quite excited about their recent demonstrations of the existence of nuclear spin states whose lifetime exceeded T₁ – up to then unanimously believed to be a hard limit to nuclear spin states’ lifetime. The very first two papers on the phenomenon had just been published and I was assigned the task to carry the research forward. I liked the idea very much; mainly because the topic embraces a good amount of spin dynamics in the derivation of new analytical equations to describe the relaxation of such spin states or the development of new pulse sequences, the use of synthetic chemistry to design molecules supporting those states and a good level of thinking and imagination to exploit these findings into some useful applications. It is now nearly 15 years later and I am still investigating the field as part of the activities of my own research group. Meanwhile, the potentiality of the subject was rapidly embraced by a number of colleagues worldwide and a good number of research papers has been published as a result.

In this book I invited such colleagues to share the results of their research efforts but to do so in a language that is at an introductory level so that the book can serve as a starting point of understanding for researchers who may become fascinated by the subject in the future. The book brings together 23 chapters written by experts from all over the world who are actively working on the subject. The book is divided into four parts that encompass the major theories behind the phenomenon, the methodology developed so far, the range of proposed applications and some generalisations of the original idea. In Part 1, after opening with a general overview of the topic, we lay down a symmetry-based theory for the existence of singlet order in a given spin-system and the analytical equations that describe the relaxation of such spin order under several relaxation mechanisms. In Part 2 we discuss the NMR pulse sequences developed to access and manipulate singlet order, starting with the synthetic chemistry rules to produce molecules that support such an order. Part 3 is dedicated to the exploitation of single order in a number of fields, including investigations of drug affinity, quantum computing or the study of porous media. Part 4 discusses other forms of long-lived spin order such as long-lived coherences or long-lived spin order in more complex spin systems.

Before inviting you to read this work, I would like to thank all of the authors who contributed to this book, which is clearly the result of a collective effort rather than my personal one. My most special thanks go to Malcolm Levitt, who introduced me to the topic and, as in his style, gave me the possibility to navigate the field without boundaries while being there with all his invaluable knowledge and expertise to guide me through. I am also indebted to a number of friends who worked together with me on the subject while in Malcolm's group: Jiri Bocan, Lynda Brown, Richard Brown, Marina Carravetta, Maria Concistrè, Jean-Nicholas Dumez, Stuart Elliott, Pär Håkansson, Joseph Hill-Cousin, Ole Johannessen, Alex Pop, Gabriele Stevanato and Michael Tayler as well as to a number of dedicated students and researchers who work or have worked on these ideas as members of my research group: Francesco Giustiniano, Andrew Hall, Giulia Melchiorre, Aliki Moysiadi, Sylwia Ostrowska, Sundeep Rathore and Monique Tourell.

Finally, I am very thankful to the Royal Society of Chemistry and the editor-in-chief of this series, Prof. William S. Price, for proposing that I edit this very first book on the subject of long-lived nuclear spin order.

Giuseppe Pileio

Southampton, UK