The synthesis of ~1-nm-sized Pt nanoclusters (Pt NCs) and their alloy NCs has garnered significant interest owing to their unique properties and potential applications in catalysis. Using carbon monoxide (CO) ligands, Pt NCs (Ptn(CO)m NCs; where n and m are the numbers of Pt atoms and CO ligands, respectively) can be synthesized with atomic precision. Most such NCs are not stable under atmospheric conditions, and thus few studies have been conducted on their application. However, a recently developed method for the synthesis of Pt NCs under atmospheric conditions using CO and phosphines (PR3) or thiolates (SR) as ligands (Ptn(CO)m(PR3)l or Ptn(CO)m(SR)o NCs, respectively) has emerged as a simple and convenient way to generate such NCs in large quantities. origins of the unique electronic properties of [Pt17(CO)12(PPh3)8] z remain unclear.