Professor Ridd has now retired and is no longer supervising PhD students.

Our main interest concerns the mechanism of nitration of aromatic and unsaturated systems. Such studies have been carried out in this Department for many years and, in that time, the principal mechanism of nitration (electrophilic substitution by the nitronium ion) has become well understood; a number of less common reaction paths often involving free radical intermediates remain, however, to be fully elucidated. These intermediates can be generated either by the abstraction of an electron from the organic substrate or by the addition of a radical species (e.g., NO 2 ) to the organic substrate. We have found that the technique known as Chemically Induced Dynamic Nuclear Polarisation (CIDNP) provides a particularly helpful way of investigating these reactions, including the reactions of sbstrates of biochemical interest.