Synthesis of new bis(cyclopentadienyl)yttrium complexes with ether functionalized cyclopentadienyl ligands. Crystal structure of [(C5H4CH2CH2OMe)2Y(μ-H)2BH2]

Treatment of C5H4CH2CH2OMe · Li(TMEDA) (TMEDA = N, N, N´, N´ tetramethylethylenediamine) with half an equivalent of YCl3(THF)3.5 in toluene afforded the salt- and solvent-free dimeric biscyclopentadienyl yttrium chloride [(C5H4CH2CH2OMe)2Y(μ-Cl)]2 (1). Reaction of 1 with one equivalent of LiAlH4 in THF gave the yttrium alumohydride complex [(C5H4CH2CH2OMe)2YAlH4] (2), which was transformed into [(C5H4CH2CH2OMe)2Y(μ-H)]2 (4) by expulsion of AlH3 with NEt3. Reaction of 1 with an excess of LiBH4 gave the yttrium borohydride complex [(C5H4CH2CH2OMe)2Y(μ-H)2BH2] (3), whose crystal structure has been shown to be monomeric species with yttrium-coordinated ether functions and a η2-bonded borohydride ligand