Supplementary Material for Perkin Transactions 2 This journal is © The Royal Society of Chemistry 2002 Supplementary Data (a) (b) 2+ Fig. S1. Spin density distribution of (a) 1• and (b) Mg –1• calculated by using the ADF method. 4 3 –1 –1 s –3 k HT / M 10 2 1 0 0 0.1 0.2 0.3 0.4 0.5 [Mg2+ ] / M 2+ Fig. S2. Dependence of kHT on [Mg ] for hydrogen transfer from 1H to DPPH• (white circles) and G• (black circles) in the presence of Mg(ClO4)2 in deaerated MeCN at 298 K. 2