Figure 2.

Overlay of selected experimental molecular geometries taken from (a) the crystal structures of Ni-2a at 100 K (green) and Cu-2a at 100 K (red) and (b) the crystal structures of Ni-2b at 290 K (green) and Cu-2b at 100 K (red). Hydrogen atoms and the disorder of the nitro group in the crystal structure of Ni-2a have been omitted for clarity. The N2, N3, O3, and metal atoms were superimposed using the least-squares procedure implemented in the MERCURY program.