The reaction chemistry of 2- and 3-aminoalkanethiols with [PtMe3I]4: a new example of the structural diversity of metal thiolates

The reaction of substitution of iodine in [PtMe3I]4 by 2- and 3-aminoalkanethiols, at several metal to ligand ratios and various reaction conditions in organic solvents, proceeds differently depending mainly on the aminoalkanethiol nature. The substitution by 2-diethylaminoethanethiol has led to a partial replacement of iodine affording the complexes [(PtMe3)4(μ-I){μ-S(CH2)2NEt2}3] and [(PtMe3)3{μ-I,μ-S(CH2)2NHEt2}2]I. 1H NMR data in solution for the former complex and the X-ray structure of the latter show that both are structurally related to the initial [PtMe3I]4 cubane. The replacement of iodine by 2-dimethylaminoethanethiol has led to [Pt(II){Pt(IV)Me3(SCH2CH2NMe2)2}2], as the only product. The X-ray structure of this complex can be described as consisting of two Pt(IV)Me3(SCH2CH2NMe2)2 octahedra linked to a naked Pt(II) atom by means of the thiolate sulfur atoms. Consequently, a total substitution of iodine in [PtMe3I]4 together with the reduction of Pt(IV) to Pt(II) have taken place. The reaction of [PtMe3I]4 with the cyclic 3-aminoalkanethiol HSCH(CH2CH2)2NMe and with the acyclic 3-aminoalkanethiol, HS(CH2)3NMe2, afforded the complexes Na[(PtMe3)2{μ-SCH(CH2CH2)2NMe}3], [(PtMe3)2{μ-SCH(CH2CH2)2NHMe}3]I2 and [(PtMe3)2{μ-S(CH2)3NHMe2}3]X2 (X = I or BPh4). They all consist of face-shared bioctahedral diplatinum(IV) units of general formula [Me3Pt(μ-SR)3PtMe3]z, in which the 3-aminothiolates function as bridging ligands through their sulfur atoms. Overall, in the case of 3-aminothiols there is a total replacement of iodine, which is accompanied by the disruption of the initial cubane structure.