Metal-Dithiolenes of Disubstituted Imidazolidine-2,4,5-trithione Monoanion. An Electrochemical and EPR Study

 

E. Grigiotti,^a F. Laschi,^a P. Zanello,^a,*M. Arca,^b C. Denotti, ^b F.A. Devillanova^b

 

^a Dipartimento di Chimica, Università degli Studi di Siena, Via A. Moro, 53100 Siena, Italy.

^b Dipartimento di Chimica Inorganica ed Analitica, Università degli Studi di Cagliari, S.S. 554 bivio per Sestu, 09042 Monserrato, Cagliari, Italy

 

Received 30 September 2003

 

Abstract

The electrochemical properties of a series of [M(R,R’timdt)₂] dithiolenes (M = Ni, Pd, Pt; R,R’timdt = monoanion of disubstituted imidazolidine-2,4,5-trithione) have been studied by cyclic voltammetry, controlled potential coulometry, and EPR spectroscopy. All the compounds undergo two separate one-electron reductions and one two-electron oxidation, which proceed through a single step in the case of nickel complexes, and through two separate steps in the case of palladium and platinum complexes. Inductive effects played by the R and R’ substituents influence the formal electrode potentials of the electron transfer processes. EPR spectroscopy has proved that the unpaired electron in monoanions [M(R,R’timdt)₂]^- is located on a SOMO, which, even if mainly ligand centred, is significantly contributed by the metal.

 

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^*Corresponding author. E-mail address: zanello@unisi.it