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 [Cl 2 M(tpbz)] from (R 2 C 2 S 2 )SnR′ 2 (R = CN, R′ = Me; R = Me, R′ = n Bu) or by a direct reaction between tpbz and [M(S 2 C 2 R 2 ) 2 ] (M = Ni, Pd, Pt; R = Ph, p -anisyl) in a 1:1 ratio. The formation of dimetallic [(R 2 C 2 S 2 )M(tpbz)M(S 2 C 2 R 2 )] 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 [(R 2 C 2 S 2 )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 [(Ph 2 C 2 S 2 ) 2 Pt IV (tpbz)], a presumed intermediate, are isolated from the preparation of [(Ph 2 C 2 S 2 )Pt II (tpbz)]. Heterodimetallic [(Ph 2 C 2 S 2 )Pt(tpbz)Ni(S 2 C 2 Me 2 )] is prepared from [(Ph 2 C 2 S 2 )Pt II (tpbz)]; its cyclic voltammogram, upon anodic scanning, shows two pairs of closely spaced, but resolved, 1e – oxidations corresponding first to [R 2 C 2 S 2 2 – ] – 1e – → [R 2 C 2 S • S – ] and then to [R 2 C 2 S • S – ] – 1e – → [R 2 (C=S) 2 ]. The open diphosphine of [(R 2 C 2 S 2 )M(tpbz)] can be oxidized to afford open-ended [(R 2 C 2 S 2 )M(tpbzE 2 )] (E = O, S). Synthesis of the octahedral [(dppbO 2 ) 3 Ni][I 3 ] 2 [dppbO 2 = 1,2-bis(diphenylphosphoryl)benzene] ...

Synthesis and coordination behaviour of 1H-1,2,3-triazole-4,5-dithiolates

“…More easily removable dithiol protecting groups such as 1,3-dithio-2-one derivatives, 29 or the use of dithiol derivatives of dialkyl tin, which can be reacted directly with metal precursors while avoiding the free thiols, 30 are certainly attractive alternatives. However, preparative access to triazoles via alkynes requires two independent thiol protecting groups.…”

Heterotrimetallic Assemblies with 1,2,4,5-Tetrakis(diphenylphosphino)benzene Bridges: Constructs for Controlling the Separation and Spatial Orientation of Redox-Active Metallodithiolene Groups

“…The mixture was then filtered to remove the insoluble residue. The dropwise addition of MeOH induced precipitation of [8][BArF 24 ], which was collected on a frit, washed with MeOH and then Et 2 O, and dried under vacuum. Yield: 0.113 g, 80%.…”

“…The more downfield-shifted 31 P signal in [8] + , which is due to the phosphines that are chelating Ni 2+ , has the sharp character typical of most of these complexes (Figure S85). The 31 P NMR signal for the phosphines chelating to Cu + in [8] + , however, is broad to a degree that is not observed for [(P-P) 2 Cu] + complexes until temperatures of ≤190 K are imposed. This effect may be due to hindered fluxionality about Cu + arising from the appreciably greater size of the [(Ph 2 C 2 S 2 )Ni(tpbz)] "ligands" compared to the smaller, purely organic diphosphines.…”

“…The application of these multimetal assemblies as prototype two-qubit gates was investigated using EPR spectroscopy. Samples of [8] + and [12] + were oxidized in situ converting each terminal dithiolene ligand into its monoanionic radical form. This action generates tricationic spin-triplet species, whose spectra recorded at ambient temperature provide a measure of the exchange interaction between the ligand radicals.…”

“…All observed and calculated masses represent the most intense peak in the mass envelope pattern. The [8] 3+ and [12] 3+ cation radicals were generated by chemical oxidation of [8] + and [12] + using 2 equiv of [(Br-p-C 6 H 4 ) 3 N][SbCl 6 ]. X-Band electron paramagnetic resonance (EPR) spectra were recorded on a Bruker ELEXSYS E500 spectrometer, and simulations were performed using XSophe.…”