PtII

PtII or platinum(II) is a transition metal oxidation state found in the element platinum, whose atomic number is 78. The +2 oxidation state indicates that two electrons have been removed from the neutral atom, resulting in a d8 electronic configuration. PtII species are typically square‑planar due to d8 ligand field stabilization and are commonly observed in coordination chemistry. Platin(II) complexes are widely used in homogeneous catalysis, notably in the Mizoroki–Heck and Suzuki–Miyaura cross‑coupling reactions, where the metal acts as a catalyst for carbon–carbon bond formation. They are also employed in olefin metathesis, alkene isomerisation, and selective oxidation reactions.

Popular PtII complexes include chloroplatinate(II) chloride (PtCl2) and the tetracarboxylate complexes such as [Pt(acac)2] (acetylacetonate). In biological contexts, [PtCl2(NH3)2] functions as cisplatin, one of the first platinum‑based chemotherapeutics developed for cancer treatment. The drug exploits PtII’s ability to form bifunctional DNA crosslinks, thereby inhibiting DNA replication and inducing apoptosis in rapidly dividing cells.

The platinum(II) center can coordinate a variety of ligands, including monodentate, bidentate, and polydentate organic and inorganic donors. In organometallic chemistry, PtII forms complexes such as Pt(PPh3)4 and Pt(CO)4, which are useful synthetic intermediates. The electrochemical reduction of PtII to Pt(0) occurs at relatively negative potentials, making PtII well suited for electroactive applications like electrocatalysis and sensor design.

Overall, PtII serves as a versatile oxidation state in inorganic and organometallic chemistry, with significant industrial, synthetic, and pharmaceutical importance.