Scheme 2.

(a) The scheme shows the 1–100 nm size regime with atomically precise NMs in the 1–2 nm region, and NPs in the 2–100 nm regime (where, very good monodispersity in size has been achieved, but atomic composition can vary by ± 1000's of atoms). Examples of widely investigated NMs with three classes of thiolate ligand are given under each series. (b) Widely investigated thiolate protected gold NM systems belonging to each series. NMs with; (c) aliphatic and aliphatic-like ligand, HSCH₂CH₂Ph, (d) aromatic ligand, HSPh-tBu, and (e) bulky ligand, HS-tBu are illustrated under each scheme. The thermodynamically most stable NM in the aliphatic, aromatic, and bulky series namely, Au₃₈(SCH₂CH₂Ph)₂₄, Au₃₆(SPh-tBu)₂₄, and Au₃₀(S-tBu)₁₈ NMs respectively, are highlighted. Asterix indicates unknown diameter of the NM due to lack of crystal structure.