Investigation of the Redox Properties of a Cp*Co(dithiolene) Complex. Evidence of the Formation of a Dimeric Dicationic Species:  [Cp*Co(dddt)]₂²⁺

Abstract

The synthesis and the electrochemical characterization of [(η 5 -C 5 Me 5 )Codddt] (dddt 2-) 5,6-dihydro-1,4-dithiine-2,3-dithiolate) (1) are described. The chemical oxidation of 1 by AgBF 4 leads to the formation of a bimetallic complex, [(η 5 -C 5 Me 5 )Codddt] 2 2+ (2), which has been characterized by X-ray crystallography. The 1 H NMR study reveals that 2 is diamagnetic, and this has been rationalized by extended Hu ¨ckel calculations. The addition of trimethyl phosphite on 2 gives the paramagnetic adduct [Cp*Co(dddt){P(OMe) 3 }] •+ (4). The dissociation of 2 has also been investigated electrochemically.

Reactivity and electrochemical behavior of ruthenium dithiolene complexes with coordinatively unsaturated metal centers: cycloaddition and dimerization reactions

“…oxidation have been reported [15,16], our example is the first case of the electro-oxidative dimerization of a ruthenium dithiolene complex. In oxidation process, complexes 1b and 1c showed several re-reduction waves after oxidation.…”

“…We focused on the unsaturated character of the ruthenium-sulfur bond in the dithiolene ring, and we report on the novel cycloaddition reactions into the unsaturated bond. Furthermore, metalladithiolene complexes are sometimes promoted to undergo the dimerization reactions by an oxidation [15,16]. One example, which is reported by Fourmigué et al [16] is shown in Scheme 2.…”

“…Furthermore, metalladithiolene complexes are sometimes promoted to undergo the dimerization reactions by an oxidation [15,16]. One example, which is reported by Fourmigué et al [16] is shown in Scheme 2. We also report on the novel dimerization reaction of ruthenium dithiolene complexes induced by an electrochemical oxidation.…”

Synthesis of μ-C2S44− Cobalt Complexes by Activation of the 1,3,4,6-tetrathiapentalene-2,5-dione, and Electrochemical Study of [(Cp*Co)2(μ-C2S4)]

“…Voltammetric data of 2 and its P(OMe) 3 adducts and for a dithiolene cobaltocene complex. [16] With this latter complex, it has also been shown that in the presence of a strong two-electron donor ligand the stabilization occurs via the formation of an adduct. [16] Thus, in order to explain the mechanism of the oxidation of 2 in the presence of a strong Lewis base, electrochemical experiments were conducted in CH 2 Cl 2 , where an excess of P(OMe) 3 was initially added to 2.…”

Formations and electrochemical behavior of mononuclear and binuclear molybdenum dithiolene complexes with nitrosyl ligands: Evidence for the formation of a coordinatively unsaturated species [Cp∗Mo(NO)(dithiolene)]

“…The electrochemical oxidations of the mononuclear cobalt dithiolene complex [Cp * Co(dddt)] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate) [29] and the mononuclear ruthenium dithiolene complex [(C 6 H 6 )Ru{S 2 C 2 (COOMe) 2 }] [15] undergo dimerizations. This process is a unique case, because the reduction of a dimeric dithiolene complex gives a monomer.…”