Fig. 2

Ligand binding modes on the surface of ceria nanoclusters. The different binding modes of surface carboxylate and pyridine groups in 1–3: a chelating (η ²); b µ₂-bridging; c η ²-chelating and µ₂-bridging; d µ₃-bridging; e Ce₃₈ (2) showing terminal pyridines ‘capping’ (binding to the center of) the (111) hexagons, and µ₂-carboxylates bridging edges joining two (111) facets; f Ce₃₈ (2) showing η ²:μ₂-carboxylates at edges joining (100) and (111) facets; and g Ce₄₀ (3) showing η ²:μ₂- and μ₃-carboxylates on edges of (110) facets, and µ₂-carboxylates bridging edges joining (110) and (111) facets. Colour code: Ce^IV gold, Ce^III sky-blue, O red, N blue, C grey, (100) facets dark blue; (110) facets violet; (111) facets green