Reactivity of the metalloligand [Pt<sub>2</sub>(µ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>] towards tellurium(II) thiourea complexes; Synthesis and structural characterization of the ditellurium(I) derivative [{Pt<sub>2</sub>(µ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>}<sub>2</sub>Te<sub>2</sub>]<sup>2+</sup>
Creators: name: Ryland G. Fortney-Zirker
name: Henderson, William
name: Lane, Joseph R.
name: Tiekink, Edward R. T.
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biophysics
subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: Cell Biology
subject: Genetics
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: Developmental Biology
subject: Cancer
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: FOS: Health sciences

description: Reaction of the platinum(II) sulfide metalloligand [Pt<sub>2</sub>(µ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>] with the tellurium(II) source TeCl<sub>2</sub>(tu)<sub>2</sub> (tu = thiourea) is dependent on reaction conditions employed. In the presence of added acid, the dominant species observed in the Electrospray Ionization (ESI) mass spectrum is the tetraplatinum species [{Pt<sub>2</sub>(µ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>}<sub>2</sub>Te<sub>2</sub>]<sup>2+</sup>. This contains the Te<sub>2</sub><sup>2+</sup> moiety and is related to the previously reported tellurium(I) dithiophosphinate analogue [(Ph<sub>2</sub>PS<sub>2</sub>)<sub>2</sub>Te<sub>2</sub>]. However, in the absence of acid, considerable degradation of the {Pt<sub>2</sub>S<sub>2</sub>} metalloligand occurs as evidenced by the formation of the mononuclear complex [Pt{SC(NH<sub>2</sub>)NH}(PPh<sub>3</sub>)<sub>2</sub>]<sup>+</sup> containing a deprotonated thiourea ligand, together with other thiourea-containing ions, identified by ESI MS. Likewise, attempted use of a fully-substituted thiourea, <i>viz.</i> Me<sub>2</sub>NC(S)NMe<sub>2</sub> (tmtu) in TeCl<sub>2</sub>(tmtu)<sub>2</sub>, also resulted in degradation of the {Pt<sub>2</sub>S<sub>2</sub>} core and detection of the known complex [(Ph<sub>3</sub>P)<sub>2</sub>PtCl{SC(NMe<sub>2</sub>)<sub>2</sub>}]<sup>+</sup>. The [{Pt<sub>2</sub>(µ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>}<sub>2</sub>Te<sub>2</sub>]<sup>2+</sup> cation was isolated with several anions, and unequivocal confirmation of the structure of the complex was obtained by an X-ray structure determination on the BF<sub>4</sub><sup>-</sup> salt, which shows the presence of the Te<sub>2</sub><sup>2+</sup> unit, with the Te–Te bond bridged by two {Pt<sub>2</sub>S<sub>2</sub>} metalloligands. Density functional theory (DFT) was used to further probe the Te<sub>2</sub><sup>2+</sup> bonding interactions in [{Pt<sub>2</sub>(μ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>}<sub>2</sub>Te<sub>2</sub>]<sup>2+</sup> and the previously reported [(Ph<sub>2</sub>PS<sub>2</sub>)<sub>2</sub>Te<sub>2</sub>]. Using a mass spectrometry-directed synthesis strategy, the ditellurium(I) species [{Pt<sub>2</sub>(μ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>}<sub>2</sub>Te<sub>2</sub>]<sup>2+</sup> was identified in reactions of [Pt<sub>2</sub>(μ-S)<sub>2</sub>(PPh<sub>3</sub>)<sub>4</sub>] with TeCl<sub>2</sub>(thiourea)<sub>2</sub>, and subsequently structurally characterised