In this work, the hexametallic dithiolene cages [M(S₂C₂Ph₂)]₆(M = Ni, Pd or Pt) have been synthesized and characterized. The motivation behind this effort was the anticipation of reversible electrochemistry suggesting these hexamers could be stable in more than one oxidation state, as seen in [Pd(S₂C₂(COOMe)₂)]₆. The first of these clusters, [Ni(S₂C₂Ph₂)]₆, was originally reported by Schrauzer et al., as a byproduct of reacting Ni(S₂C₂Ph₂)₂ with alkynes to produce thiophenes. Later, it was observed as a byproduct arising from a variety of dithiolene transfer reactions. Adams et al. was first to fully characterize [Ni(S₂C₂Ph₂)]₆ and publish a crystal structure of it. Charge neutral hexapalladium dithiolene cages with electron withdrawing substituents were synthesized by Beswick et al., followed by Wrixon and Moscattini. No compound of the type has previously been prepared with platinum. In addition to the synthesis and structural characterization of these cage compounds, DFT-calculated assessments of their electronic structures show the HOMOs to be mixed dithiolene ligand-metal in character, qualitatively quite similar to the HOMOs of [M(S₂C₂Ph₂)₂] series, while the LUMO and higher lying virtual MOs are substantially metal in character. The cyclic voltammetry of these clusters reveals reversible processes in both the oxidizing and reducing directions, which have been characterized by spectroelectrochemical means.

Prof. Dr. Serena DeBeer

Max-Planck-Institute

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