Redox properties of mixed tetraamino complexes of tetravalent platinum

Conclusions

• 1. Isomeric complexes of di- and tetravalent platinum with mixed acidoligands of the type of A₂B₂PtCl₂ and A₂B₂Cl₂PtCl₂ (A, B=NH₃, CH₃NH₂, C₂H₅NH₂, n-C₃H₇NH₂, i-C₃H₇NH₂, (CH₃)₂NH, n-C₄H₉NH₂) were synthesized and characterized. A crystallooptical characterization of the synthesized compounds was given.

• 2. The redox potentials (E₀) of systems containing of mixed tetraamino complexes of Pt(II) and Pt(IV) were measured.

• 3. The nature of the change in the values of the redox potential depends on the σ-donor character of the nitrogen of the aliphatic ligand, the size of the molecule, and the isomerism of the amine. Sterically more conjugated aminoligands with a. branched chain at the carbon and nitrogen atoms sharply increase the redox potential, stabilizing complexes of Pt(II).

• 4. The presence of a ring-forming ligand in the complex greatly increases the stability of complexes of Pt(IV), leading to a decrease in the values of the redox potential.

• 5. Isomerism of the complex has practically no effect on the values of E₀ of the corresponding systems.

• 6. A weak dependence of E₀ on the temperature was detected for systems containing the complexes (CH₃NH₂)₂(n-C₄H₉NH₂)₂Cl₂PtCl₂, (CH₃NH₂)₂·[(CH₃)₂NH]₂Cl₂PtCl₂. The thermodynamic functions for these compounds were calculated.