Synthesis,Thermal Isomerization in Solution and in Solid Phase of the Complexes [Pt(RCN)2Cl2]

The interaction of the clathrate Pt₆Cl₁₂ · 0.1 EtCl · 5.7H₂O with RCN nitriles results in cis-Pt(PhCH₂CN)₂Cl₂] and in Pt(RCN)₂Cl₂] (R = CH₂CO₂Et, Ph) complexes as a mixture of cis- and trans-isomers which separated and characterized. Cis-Pt(MeCN)₂Cl₂] has been synthesized using a well known technique of K₂PtCl₄] interaction with acetonitrile in water. Heating cis-Pt(RCN)₂Cl₂] (R = Me, CH₂Ph, CH₂CO₂Et) in the solid phase leads to cis-trans isomerization. In case of cis-Pt(PhCN)₂Cl₂] thermal conversion results in trans-Pt(PhCN)₂Cl₂] but the process of geometrical isomerizations accompained by a considerable decomposition of starting material and/or final products. Boiling of cis-Pt(PhCH₂CN₂)Cl₂] in mixture of EtNO₂? PhCH₂CN or cis-Pt(EtCO₂CH₂CN)₂Cl₂] in MeNO₂ or EtNO₂ solutions results in complete cis-trans conversion. Similarily heating of cis-Pt(RCN)₂Cl₂] (R = Me, Ph) in solution produces an equilibrium mixture of cis- and transisomers.