Transplatin
{{Chembox
| ImageFile = TransPtCl2A2.svg
| ImageFileL1 = Transplatin-3D-balls.png
| ImageFileR1 = Transplatin-3D-vdW.png
| ImageSize = 144
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| Name = trans-Dichlorodiammineplatinum(II)
| IUPACName = (SP-4-1)-diamminedichloridoplatinum(II)
| OtherNames = Reiset's second chloride, transplatin
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| Section1 = {{Chembox Identifiers
| CASNo = 14913-33-8
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = BW0OY6ZTD4
| PubChem = 5702198
| ChemSpiderID =
| InChI=1S/2ClH.2H3N.Pt/h2*1H;2*1H3;/q;;;;+2/p-2
| InChIKey = LXZZYRPGZAFOLE-UHFFFAOYSA-L
| SMILES = N.N.[Pt+2].[Cl-].[Cl-]
| SMILES_Comment = ionic form
| SMILES1 = Cl[Pt-2](Cl)([NH3+])[NH3+]
| SMILES1_Comment = coordination form}}
| Section2 = {{Chembox Properties
| Pt=1|Cl=2|N=2|H=6
| MolarMass =
| Appearance = yellow solid
| Density =
| MeltingPt =
| BoilingPt =
| Solubility = low}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
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trans-Dichlorodiammineplatinum(II) is the trans isomer of the coordination complex with the formula trans-PtCl2(NH3)2, sometimes called transplatin.{{cite journal |pmid=16918130 |title=Transplatin, a cisplatin trans-isomer, may enhance the anticancer effect of 5-fluorouracil |journal=Journal of Experimental & Clinical Cancer Research |volume=25 |issue=2 |pages=195–200 |date=25 June 2006|last1=Nakata |first1=B |last2=Yamagata |first2=S |last3=Kanehara |first3=I |last4=Shirasaka |first4=T |last5=Hirakawa |first5=K }} 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.{{cite book |title=Inorganic Syntheses |volume=VII |year=1963 |pages=239–245 |doi=10.1002/9780470132388.ch63 |isbn=978-0-470-13238-8|last1=Kauffman |first1=George B |last2=Cowan |first2=Dwaine O |last3=Slusarczuk |first3=George |last4=Kirschner |first4=Stanley |chapter=cis - and trans -Dichlorodiammineplatinum(II) }} It belongs to the molecular symmetry point group D2h.
Preparation and reactions
The complex is prepared by treating [Pt(NH3)4]Cl2 with hydrochloric acid.
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.{{cite journal |title=Towards Antitumor Active trans-Platinum Compounds |journal=European Journal of Inorganic Chemistry |year=2009 |volume=2009 |issue=10 |pages=1293–1302 |doi=10.1002/ejic.200801118 |pmc=2821104|last1=Aris |first1=S. M |last2=Farrell |first2=N. P |pmid=20161688}}