Reaction of Tetrahydroxo(2,2-dimethylpropane- diamine)platinum(IV) with Trimethylsilylchoride. Pentacoordinative Si···OH Interaction Labilizing the PtIV−OH Bond

Electrophilic substitution reaction of (dmpda)Pt(OH)4 (dmpda = 2,2-dimethylpropanediamine) with trimethylsilyl chloride gave only axially substituted disiloxyplatinum(IV) complexes. Instead of further silylation, one or both equatorial hydroxide ligands were replaced by chloride ion, yielding (dmpda)Pt(OSiMe3)2Cl(OH) (1) and (dmpda)Pt(OSiMe3)2Cl2 (2) at room and refluxing temperatures, respectively. Such nucleophilic substitution of hydroxide ligand by chloride ion is presumed to be assisted by pentacoordinative Si···OH interaction labilizing the PtIV−OH bond.