Metallic Coordination Polymers Using CS2 as Starting Material

Abstract

Organic polymers with “metallic” properties have found widespread interest during the last few years /1,2/. Acetylene and aniline as well as different nitrogen and sulfur heterocycles have been used as starting materials. One main problem hampering the technical application of these solids up to now is their environmental and thermal instability. Therefore, we introduced metal ions to stabilize polymeric backbones with high electrical conductivity. Because of the enormous coordination ability of sulfur to many transition metal ions we decided to use a polymeric carbon-sulfur backbone. In view of a future technical application one has to start from less expensive and readily available chemicals like CS2 e.g., in order to obtain a carbon-sulfur polymer. Since CS2 cannot be readily polymerized to highly conducting solids a different approach has to be found. As reported earlier /3,4,5/ CS2 can be reacted to thiapendione which can be converted into ethylenetetrathiolate (TT) by cleavage with stronq chemical bases. Additionally thiapendione can be “dimerized” to bis(1,3-dithiole-2-one)tetra-thiafulvalene which can be converted into tetrathiolatotetra-thiafulvalene (TTF-TT) again by a cleavage reaction with strong bases. Both tetrathiolates react with transition metal ions like nickel(II) or copper(II) to coordination polymers which are remarkably inert chemically as well as thermally /6/. The reactions and their final products are schematically summarized in figure 1.