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

The interaction of the clathrate Pt 6 Cl 12 · 0.1 EtCl · 5.7H 2 O with RCN nitriles results in cis‐[Pt(PhCH 2 CN) 2 Cl 2 ] and in [Pt(RCN) 2 Cl 2 ] (R = CH 2 CO 2 Et, Ph) complexes as a mixture of cis‐ and trans‐isomers which separated and characterized. Cis‐[Pt(MeCN) 2 Cl 2 ] has been synthesized using a well known technique of K 2 [PtCl 4 ] interaction with acetonitrile in water. Heating cis‐[Pt(RCN) 2 Cl 2 ] (R = Me, CH 2 Ph, CH 2 CO 2 Et) in the solid phase leads to cis‐trans isomerization. In case of cis‐[Pt(PhCN) 2 Cl 2 ] thermal conversion results in trans‐[Pt(PhCN) 2 Cl 2 ] but the process of geometrical isomerizations accompained by a considerable decomposition of starting material and/or final products. Boiling of cis‐[Pt(PhCH 2 CN 2 )Cl 2 ] in mixture of EtNO 2 PhCH 2 CN or cis‐[Pt(EtCO 2 CH 2 CN) 2 Cl 2 ] in MeNO 2 or EtNO 2 solutions results in complete cis‐trans conversion. Similarily heating of cis‐[Pt(RCN) 2 Cl 2 ] (R = Me, Ph) in solution produces an equilibrium mixture of cis‐ and transisomers.