PREPARATION OF A NOVEL THALLIUM COMPOUND OF CORE FORMULA, TLMO6S88+

A new mixed metal cluster of molybdenum, sulfur and thallium has been prepared. The complex can be prepared by the reaction of [Mo3S4(H2O)(9 )](4+) with thallium metal, but preparation is more successful using s odium borohydride reduction of a solution of [Mo3S4(H2O)(9)](4+) in th e presence of solid TlCl. The new compound occurs as a turquoise solut ion when eluted in 4 M HCl or Hpts (p-toluenesulfonic acid) from a Dow ex chromatography column. ICP analysis on the pure solution indicates a ratio of 5.92:1 for the ratio Mo:Tl, confirming the proposed core fo rmula of TlMo6S88+. The charge on the core has been confirmed as 8+ us ing stoichiometric experiments with ferric solutions. The compound has proven to be thermally unstable, eluting only from ice-cooled columns . On warming a solution from 10 to 25 degrees C, a gas can be seen to evolve, presumably hydrogen. The thermal instability has been investig ated further to yield values of Delta H double dagger = 79 kJ mol(-1), Delta S double dagger = -39 mol(-1).