Transplatin

trans-Dichlorodiammineplatinum(II) is the trans isomer of the coordination complex with the formula trans-PtCl₂(NH₃)₂, sometimes called transplatin.^[1] It is a yellow solid with low solubility in water but good solubility in DMF. The existence of two isomers of PtCl₂(NH₃)₂ led Alfred Werner to propose square planar molecular geometry.^[2] It belongs to the molecular symmetry point group D_2h.

trans-Dichlorodiammineplatinum(II)

Names
IUPAC name (SP-4-1)-diamminedichloridoplatinum(II)
Other names Reiset's second chloride, transplatin
Identifiers
CAS Number	14913-33-8 Y
3D model (JSmol)	ionic form: Interactive image coordination form: Interactive image
ECHA InfoCard	100.035.422
PubChem CID	5702198
UNII	BW0OY6ZTD4 Y
InChI InChI=1S/2ClH.2H3N.Pt/h2*1H;2*1H3;/q;;;;+2/p-2 Key: LXZZYRPGZAFOLE-UHFFFAOYSA-L
SMILES ionic form: N.N.[Pt+2].[Cl-].[Cl-] coordination form: Cl[Pt-2](Cl)([NH3+])[NH3+]
Properties
Chemical formula	Cl2H6N2Pt
Molar mass	300.05 g·mol−1
Appearance	yellow solid
Solubility in water	low
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation and reactions

The complex is prepared by treating [Pt(NH₃)₄]Cl₂ with hydrochloric acid.^[2]

Many of the reactions of this complex can be explained by the trans effect. It slowly hydrolyzes in aqueous solution to give the mixed aquo complex trans-[PtCl(H₂O)(NH₃)₂]Cl. Similarly it reacts with thiourea (tu) to give colorless trans-[Pt(tu)₂(NH₃)₂]Cl₂. In contrast, the cis isomer gives [Pt(tu)₄]Cl₂. Oxidative addition of chlorine gives trans-PtCl₄(NH₃)₂.

Medicinal chemistry

trans-Dichlorodiammineplatinum(II) has had far less impact on medicinal chemistry compared to its cis isomer, cisplatin, which is a major anticancer drug. Nonetheless, replacement of the ammonia with other ligands has led to highly active drugs that have attracted much attention.^[3]