Structural Factors Governing the Formation of Extended Structures in Group 10 and 12 Metal-Dithiolenes

Abstract

A series of metal-dithiolene compounds have been prepared by direct reactions between MCl2·6H2O (M = Ni, Zn) or HgCl2 with HSC6H2X2SH (X = Cl or H) in the presence of a base. The fine-tuning of the reaction conditions has allowed us to rationalize part of the structural factors governing the formation of coordination polymers versus discrete metal-dithiolene complexes. With the aim to gain knowledge of the formation of extended metal–organic structures, we have also studied the reaction between Na­[Ni­(SC6H2Cl2S)2] and HgCl2. These reactions lead to the formation of either discrete compounds or extended structures. The detailed structural analysis of 11 compounds has allowed us to uncover some relevant clues about the formation of coordination polymers based on dithiolenes. We have observed that extended structures are typically formed when: (i) the sulfur atoms apart from being involved in the chelation of the transition metal center also coordinate to the alkaline metal center; i.e., dithiolene acts as a bridging ligand; (ii) water molecules preferentially coordinate to alkaline centers mostly acting as bridging molecules; and (iii) bulkier alkaline cations are employed to allow a greater number of sulfur atoms coming from the metal-dithiolene entities to be incorporated in their coordination sphere. The results obtained ensure that a combination of at least two of these features gives rise to polymeric coordination entities.