Oxidative addition of tetrathiocins to palladium(0) and platinum(0): a route to dithiolate coordination complexes

Abstract

<p>Functionalized benzenedithiolate complexes of Pt and Pd were prepared by oxidative addition of a library of 1,2,5,6-tetrathiocins to M₂(dba)₃. The oxidation potentials of crown-ether derivatives were increased upon binding Na⁺ ions.</p>

Oxidative addition of 1,2,5,6-Tetrathiocins to Co(I): A Re-Examination of Crown Ether Functionalized Benzene Dithiolate Cobalt(III) Complexes

“…On the basis of the DFT calculations (Figure 3), the HOMO is largely dithiolateligand-based, yet oxidation of 3 is shifted to a considerably more positive potential when compared to the analogous Pd(dppe) and Pt(dppe) complexes with the same 15-crown-5benzenedithiolate ligand (+0.52 and +0.58 V vs Ag/AgCl, respectively) whose HOMO is similarly of dithiolate character. 23 This likely arises as a consequence of the higher oxidation state of the Co(III) lowering the HOMO energy. Unlike the Pd(dppe) and Pt(dppe) derivatives, this oxidation is irreversible.…”

“…Ligand 1 was prepared according to the literature method. 23 Caution! The microwave reactions to prepare 3 and 4 are carried out in a sealed glass vial evolve CO.…”

“…Their synthetic method is lengthy, and several intermediates were incompletely characterized and/or yields not reported. , An alternative synthetic strategy to access dithiolate complexes is the oxidative addition of dithietes to low-valent metals . This methodology has recently been exploited by Fekl and Kuropatov who examined oxidative addition of dithietes to Pd(0). , In this context, we have explored the related benzo-fused1,2,5,6-tetrathiocins which can be considered as dimers of the dithiete moiety and exhibit similar reactivity to zero-valent group 10 metal complexes. − …”

Use of Crown Ether Functions as Secondary Coordination Spheres for the Manipulation of Ligand–Metal Intramolecular Electron Transfer in Copper–Guanidine Complexes

“…The encapsulation of Na + leads to an anodic shift of ∼60 mV of the Fe III /Fe II reduction potential. The second example in Figure 2 a, a palladium complex with a crown ether function attached to a benzenedithiolate ligand, reveals an anodic shift of 100 mV for the ligand‐based oxidation upon Na + binding [41] . The electronic structure of the crown ether incorporated Co(salen) complex shown on the left side of Figure 2 b is only slightly affected by metal encapsulation [37] .…”

“…Thes econd example in Figure 2a, ap alladium complex with ac rown ether function attached to ab enzenedithiolate ligand, reveals an anodic shift of 100 mV for the ligand-based oxidation upon Na + binding. [41] The electronic structure of the crown ether incorporated Co(salen) complexs hown on the left side of Figure 2b is only slightly af-fected by metal encapsulation. [37] The effect on the redox potential is therefore predominantly an electrostatic effect rather than an inductive effect.F inally,i ron complexes with pyridinediimine ligands( PDI), showing intriguing electronic structures and redox properties (ligand-based oxidation and metal-based reduction), [42] were modified with pendant crowne ther groups (see Lewis structure on the right side of Figure 2b).…”