Metal/Metal Redox Isomerism Governed by Configuration

Abstract

A pair of diastereomeric dinuclear complexes, [Tp′(CO)BrW{μ‐η2‐C,C′‐κ2‐S,P‐C2(PPh2)S}Ru(η5‐C5H5)(PPh3)], in which W and Ru are bridged by a phosphinyl(thiolato)alkyne in a side‐on carbon P,S‐chelate coordination mode, were synthesized, separated and fully characterized. Even though the isomers are similar in their spectroscopic properties and redox potentials, the like‐isomer is oxidized at W while the unlike‐isomer is oxidized at Ru, which is proven by IR, NIR and EPR‐spectroscopy supported by spectro‐electrochemistry and computational methods. The second oxidation of the complexes was shown to take place at the metal left unaffected in the first redox step. Finally, the tipping point could be realized in the unlike isomer of the electronically tuned thiophenolate congener [Tp′(CO)(PhS)W{μ‐η2‐C,C′‐κ2‐S,P‐C2(PPh2)S}Ru(η5‐C5H5)‐(PPh3)], in which valence trapped WIII/RuII and WII/RuIII cationic species are at equilibrium.

Tuning the potential of redox-active diphosphine ligands based on the alkyne complexes [Tp*W(CO)L{η2-C2(PPh2)2}]

“…In recent years, some studies on this topic have appeared with different heteroatoms (S, N, and P) as donor atoms at the alkyne. 13 We further demonstrated that the oxidized open-shell diphosphine [Tp*W(CO)I(dppa)] + is capable of cleaving NO. 10…”

Migratory insertion of isocyanide into a ketenyl–tungsten bond as key step in cyclization reactions

“…Side-on alkyne complexes with thiolate, 43–45 amide 46,47 or phosphine 48,49 substitution in both α-positions represent chelates, which can serve as redox-active metallo-ligands. 50 In the course of this studies aiming at alkyne complexes with direct oxygen-substitution we obtained a mononuclear W-complex with the prototypical κ 1 -ketenyl ligand C(H)CO. Reactivity studies uncovered a facile cyclisation reaction with isocyanides.…”