Fig. 2. Side and top view representations of charge density differences among (a) Gd–DOTA, (b) 213Bi–DOTA, (c) 217At–DOTA, (d) 217Fr–DOTA and (e) 225Ac–DOTA chelates. Yellow surfaces correspond to regions with electron accumulation, while blue surfaces correspond to regions with electron depletion. The charge density isosurface value is ρ = 3.49 × 10–3 e Å–3. Only ions with neighbour O, N and C atoms are shown since distant atoms are not participating in the charge transfer.
