Trans–cis isomerization of [(C6H5)3P]2PtCl2 complex in dimethylformamide solutions

The kinetics of the trans–cis isomerization reactions of the [(C6H5)3P]2PtCl2 neutral complex catalyzed by four different metal ions: Be2+, Mg2+, Ca2+ and Sr2+ has been studied. The isomerization reactions were investigated in dimethylformamide (DMF) solutions at five temperatures in the range of 278–298 K keeping a constant concentration of metal ions c = 0.5 M. The rates of the isomerization reactions were determined spectrophotometrically by monitoring the absorbance changes at the 277 nm wavelength. The spectral measurements were carried out in the UV–Vis region using the Perkin–Elmer Lambda 650 instrument with the scan accuracy of 1 nm and 1 nm slit width at the 120 scanning rate. The observable rate constants were computed using the “Glint” program based on the global analysis. The activation energies were determined using the Arrhenius equation. The differences in the structures of the obtained cis and trans geometric isomers were confirmed on the basis of their IR spectra.