Formation and structure of thulium(III) cyclopentadienides as products of reactions directed towards the synthesis of thulium(II) cyclopentadienides

TmI2(THF)(2) and [C5Me5]K react in THF to yield the Tm-III complex (C5Me6)( 2)TmI(THF) (1). The reaction of 1 with excess sodium in 1,2-dimethoxyethane (DME) leads, through Tm-II intermediates and a reductive splitting of DME solvent molecules, to the trisodium dithulium(III) complex [(DME)(2)Na(mu-e ta (5):eta (5)-C5Me5)Tm(eta (5)-C5Me5) (mu (2)-OMe)(2)(Na-mu-eta (5):eta (5 )-C5Me5)Na(mu -OMe)(2)Tm(eta (5)-C5Me5)(2)] (2). Treatment of TmI2(THF)2 wi th [(Me3Si)(2)C5H3]MgCl (3) in THF yields the dimeric Train complex [{1,3-( Me3Si)(2)C5H3}(2)TmCl](2) (4), while TmI3(THF)(3) reacts with [C5H4CH2CH2NM e2]K(THF) (5) to yield solvent-free (C5H4CH2CH2NMe2)(2)TmI (6). The new Tm- III compounds have been characterized by elemental analysis, IR spectroscop y, and mass spectrometry. The molecular structures of 2, 4, 5, and 6 have b een determined by single-crystal X-ray diffraction analysis.