| Abstract
| - When VCl3 is dissolved in a Lewisbasic room-temperature molten salt consisting of1-ethyl-3-methyl-1H-imidazolium chloride and aluminumchloride, 3 equiv of chloride are added stepwise, forming higher ordercomplexes. Each of the vanadium(III) complexes formed can bereversibly oxidized to a corresponding vanadium(IV) complex.The potentials for the couples VCl4- ↔VCl4 + e-,VCl52- ↔VCl5- + e-, andVCl63- ↔VCl62- + e- occurat 1.33, 1.23, and 1.00 V, respectively, measured versus anAl/AlCl3 reference. Although other transition metalsare known to form higher order complexes in such melts, this is thefirst case where the stepwise addition of chloride accompanied byreversible electrochemistry has beendemonstrated.
- Complexes of VCl3 and VCl4 have beenformed in a Lewis basic room-temperature molten salt consistingof1-ethyl-3-methyl-1H-imidazolium chloride and aluminumchloride. Electrochemical and spectroscopic studiesshow that 3 equiv of chloride can be added to VCl3 to formhigher order chloride complexes. Each vanadium(III) complex can be reversibly oxidized to a correspondingvanadium(IV) complex. The potentials for thecouplesVCl4- ↔ VCl4 +e-, VCl52- ↔VCl5- + e-, andVCl63- ↔VCl62- + e- occurat 1.33, 1.23, and 1.00 V, respectively, measured versus a reference electrode consisting of an aluminumwire in a 0.6 mole fraction AlCl3 melt.Although higher order chloride complexes of other transitionmetals have been reported in these melts, this is thefirst metal for which the stepwise addition of chloride accompanied byreversible electrochemistry for each specieshas been demonstrated. This also shows that molten salts areuseful for stabilizing complexes which may behydrolyzed by the residual water sometimes present in organicsolvents.
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