Crystallization‐Induced Asymmetric Synthesis of Nonracemic Platinum(IV) Polysulfide Tris(chelate) Complexes

Abstract

The random nonracemic formation of the platinum(IV) polysulfide tris(chelate) anionic complex (NH4)2[Pt(S5)3]·2H2O, previously believed to be due to a crystallization‐induced asymmetric transformation of the reaction product, under scrutiny turned out to be a new type of autocatalytic asymmetric synthesis. The synthesis is driven by simultaneous crystallization of the product as an enantiomorphous conglomerate. In particular, the preparation becomes chemo‐ and stereoselective when carried out with continuous vigorous stirring in the presence of seeds of the desired nonracemic ultimate reaction product, i.e. an autocatalyst. However, structural characterization of the randomly obtained products by means of XRD, 195Pt NMR, and ESI‐MS measurements as well as X‐ray single‐crystal analyses, reveals the significant complexity of the reaction. Several tris(polysulfide) congeners and their stereoisomers are usually obtained, and they may even cocrystallize. All these characteristics point to the kinetic control of these autocatalytic asymmetric preparations under the applied nontrivial reaction conditions. Consequently, the composition and handedness of the products can to a large extent be controlled by seeding the reaction mixture with a small previously obtained solid sample, which contributes to the synthesis as an autocatalyst.

Oxidizing Elemental Platinum with Oleum under Harsh Conditions: The Unique Tris(disulfato)platinate(IV) [Pt(S2O7)3]2− Anion

“…[22] The [Pt(S 2 O 7 ) 3 ] 2À anion is a chiral complex, but a differentiation between the L and the D enantiomers is not observable in the inversion symmetric crystal However, if the [Pt(S 2 O 7 ) 3 ] 2À anion is the first example of a noble metal in coordination of three inorganic and oxoanionic chelating ligands, there are nice examples of chelate complexes with noble metals coordinated by polysulfide ligands, for example, the platinum species [Pt(S 5 ) 3 ] 2À . [23] The motif of the oxoanionic complex in 1 has been observed by us only recently for a number of other elements, namely, Si, Ge, Sn, and Ti. [24][25][26][27] With respect to the distances MÀO, the platinum compound integrates into this row between titanium and tin.…”

“…However, if the [Pt(S 2 O 7 ) 3 ] 2− anion is the first example of a noble metal in coordination of three inorganic and oxoanionic chelating ligands, there are nice examples of chelate complexes with noble metals coordinated by polysulfide ligands, for example, the platinum species [Pt(S 5 ) 3 ] 2− 23. The motif of the oxoanionic complex in 1 has been observed by us only recently for a number of other elements, namely, Si, Ge, Sn, and Ti 24–27.…”

The Synthesis of Low Pt loading Agcore- Pt atoms-exposedshell Structure by Ligand Exchange Method with High Electrocatalytic Performance for Hydrogen Evolution Reaction

“…To start with, the Pt polysulfide precursor and Ag nanoparticles (Ag) could be synthesized as described in previous reports [13][14][15][16][17] . Then, the ligand exchange reaction was initiated between Pt polysulfide and Ag nanoparticles.…”

Exploring Platinum Speciation with X-ray Absorption Spectroscopy under High-Energy Resolution Fluorescence Detection Mode

“…The synthesis of the (NH 4 ) 2 Pt IV (S 5 ) 3 solid has been a subject of several studies using different protocols of variable complexity [65][66][67][68]. We have adopted the method of [68], which is the most straightforward way of avoiding the use of highly toxic carbon disulfide CS 2 .…”