Monovalent Thulium. Synthesis and Properties of TmI

The reaction of thulium shavings with iodine at 680°C gave a poorly separable product mixture A, consisting of thulium metal (65%), TmI 2 (14%), and TmI (21%). Monovalent thulium iodide could not be isolated in a pure state, but its presence among the products was confirmed, apart from magnetic measurements, by reactions with naphthalene and perylene, which proceed under mild conditions. The reaction of TmI with naphthalene, which takes place at – 40°C, affords the trivalent thulium complex with naphthalene dianion, [TmI(C 10 H 8 )(DME) 3 ]. The multistep reaction with perylene starts with the formation of the divalent thulium radical anion complex, [(TmI) + (C 20 H 12 ) – • (DME) 3 ], and ends in the formation of trivalent thulium complex, [(TmI) 2+ (C 20 H 12 ) 2 – (DME) 3 ]. The presence of a radical anion intermediate in the reaction mixture in an early stage was confirmed by ESR spectroscopy.