[Fe(qdt) 2 ] − salts; an undimerised Fe III bisdithiolene complex stabilised by cation interactions

(n-Bu)4N[Fe(qdt)2] provides the first example of an undimerised FeIII bisdithiolene complex with well isolated square planar coordinated [Fe(qdt)2]− units, due to short apical Fe⋯H, Fe⋯C and S⋯H contacts with the cations, while the tetraphenylarsonium salt of this complex presents the usual dimerisation as [Fe(qdt)2]22−, with square-based pyramidal coordination of Fe.