Anionic and neutral bis(diimine)lanthanide complexes

Oxidation of ytterbium(II) complex (dpp-BIAN)Yb(DME)2 (1) with dpp-BIAN affords an ionic compound [(dpp-BIAN)2Yb]−[(dpp-BIAN)Yb(DME)2]+ (2) (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene), in which the oxidation states of the metals in anionic and cationic counterparts are different. Structurally related lanthanum(III) complex [(dpp-BIAN)2La]−[(dpp-BIAN)La(DME)2]+ (3) has been prepared reacting excess of metallic lanthanum with dpp-BIAN. Compound [(dpp-BIAN)2La]−[K(Et2O)4]+ (4) has been isolated from the reaction of LaI3 with three molar equivalents of potassium and one molar equivalent of dpp-BIAN in diethyl ether. The reaction of SmI2 with dpp-BIAN and potassium affords complex [(dpp-BIAN)2Sm]−[K(C6H6)]+ (5). Treatment of compound 5 with 0.5 molar equivalent of iodine produces neutral complex (dpp-BIAN)2Sm (6). Molecular structures of complexes 2–6 have been determined by X-ray crystallography.