Open-Ended Metallodithiolene Complexes with the 1,2,4,5-Tetrakis(diphenylphosphino)benzene Ligand: Modular Building Elements for the Synthesis of Multimetal Complexes.

ABSTRACT: Open-ended, singly metalated dithiolene complexes with 1,2,4,5-tetrakis(diphenylphosphino)benzene (tpbz) are prepared either by ligand transfer to [Cl₂M(tpbz)] from (R₂C₂S₂)SnR'₂ (R = CN, R' = Me; R = Me, R' = ⁿBu) or by a direct reaction between tpbz and [M(S₂C₂R₂)₂] (M = Ni, Pd, Pt; R = Ph, p-anisyl) in a 1:1 ratio. The formation of dimetallic [(R₂C₂S₂)M(tpbz)M(S₂C₂R₂)] attends these syntheses in modest amounts, but the open-ended compounds are readily separated by silica chromatography. As affirmed by X-ray crystallographic characterization of numerous members of the set, the [(R₂C₂S₂)M(tpbz)] compounds show dithiolene ligands in their fully reduced ene-1,2-dithiolate form conjoined with divalent Group 10 ions. Minor amounts of octahedral [(Ph₂C₂S₂)₂Pt^IV(tpbz)], a presumed intermediate, are isolated from the preparation of [(Ph₂C₂S₂)Pt^II(tpbz)]. Heterodimetallic [(Ph₂C₂S₂)Pt(tpbz)Ni(S₂C₂Me₂)] is prepared from [(Ph₂C₂S₂)Pt^II(tpbz)]; its cyclic voltammogram, upon anodic scanning, shows two pairs of closely spaced, but resolved, 1e^- oxidations corresponding first to [R₂C₂S₂^2-] - 1e^- → [R₂C₂S^•S^-] and then to [R₂C₂S^•S^-] - 1e^- → [R₂(C═S)₂]. The open diphosphine of [(R₂C₂S₂)M(tpbz)] can be oxidized to afford open-ended [(R₂C₂S₂)M(tpbzE₂)] (E = O, S). Synthesis of the octahedral [(dppbO₂)₃Ni][I₃]₂ [dppbO₂ = 1,2-bis(diphenylphosphoryl)benzene] suggests that the steric profile of [(R₂C₂S₂)M(tpbzE₂)] is moderated enough that three could be accommodated as ligands around a metal ion.

SUBMITTER: Kumar S 

PROVIDER: S-EPMC8424627 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature