Immobilization of Platinum(II) and Platinum(IV) Complexes on Oxidized Nanoporous Carbon Material and Evaluation of the Enthalpy of Adsorption

Abstract

Physicochemical study of cis-[Pt(NH3)2Cl2] and cis-[Pt(NH₃)₂Cl₂(OH)₂] is carried out, and immobilization of platinum complexes on the nanoporous carbon substrate is investigated. The solubility of cis-[Pt(NH₃)₂Cl₂] in 1 M HCl solution is determined, and the average enthalpy of dissolution is calculated: Δ_solH° = 27.3 ± 0.9 kJ/mol. The batch capacity is determined experimentally for cis-[Pt(NH3)2Cl2] and cis- [Pt(NH₃)₂Cl₂(OH)₂] to be 32.9 mg/g (0.17 mg-equiv/g) and 47.6 mg/g (0.24 mg-equiv/g), respectively. Immobilization of platinum complexes on the oxidized carbon surface is found to take place due to interaction between carboxy groups and ammine groups of platinum complexes. The resulting heat capacity curves are used to calculate the enthalpies of adsorption for cis-[Pt(NH₃)₂Cl₂] and cis-[Pt(NH₃)₂Cl₂(OH)₂] on the oxidized carbon surface, equal to 24.46 and 27.46 kJ/mol, respectively.