Replacement at Square-Planar Platinum II

Unusually, base hydrolyses and dissociative processes command more attention this time than the more common nucleophilic replacements. A study by 

Erickson and co workers of the hydrolysis reactions of [PtCl(dmso) (amino acid)] (dmso is cis to N amino acids are glycine, sarcosine, or N,N-dimethylglycine) revealed a second-order assistance by Ag which dominated the conversions to the aquo ions, [Pt(OH2)(dmso)(amino acid)]. The relative importance of the unassisted (ki) path and the silver ion assisted (kAg) path is expressed by the ratio ki/(ki + kAg[Ag ]). The authors suggested the operation of reactions (1) and (2), based on chloride bridges to Ag, to account for the acceleration. Some structures described in Section 5.7 lend support to this type of interaction. 

The reaction of the aquo complex [Pt(OH2)(dien)] with its conjugate base [PtCOHjCdien)] , reaction (3), has been investigated by pH relaxation methods/  

The dimerization constant of 108 10 Mat 25 °C is similar to that previously reported for the palladium analog. In dilute solutions, or low-pH media, the extent of dimer formation from [Pt(OH2)(dien)] is small, while at high pH [Pt(OH)-(dien)] predominates, again limiting dimer formation. In addition, the rate of dimer formation is relatively slow. 

The reactions of two mole equivalents of 5 -guanosinemonophosphoric acid (5 -GMPH2) or 2 -deoxy-5 -guanosinemonophosphoric acid with cis-[Pt(OH2)2(NH3)2] proceeded in two consecutive steps displacing the water molecules. The activation parameters indicated that conventional associative activation applied. By contrast, a large, positive value for AS was obtained for the second step when the related complex ci5-[Pt(OH2)2(NH2Pr )2] was allowed 

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