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

Treatment of C 5 H 4 CH 2 CH 2 OMe·Li(TMEDA)(TMEDA  N, N, N′, N′ tetramethylethylenediamine) with half an equivalent of YCl 3 (THF) 3.5 in toluene afforded the salt- and solvent-free dimeric biscyclopentadienyl yttrium chloride [(C 5 H 4 CH 2 CH 2 OMe) 2 Y-(μ-Cl)] 2 ( 1 ). Reaction of 1 with one equivalent of LiAlH 4 in THF gave the yttrium alumohydride complex [(C 5 H 4 CH 2 CH 2 OMe) 2 -YAlH 4 ] ( 2 ), which was transformed into [(C 5 H 4 CH 2 CH 2 OMe) 2 Y(μ-H)] 2 ( 4 ) by expulsion of AlH 3 with NEt 3 . Reaction of 1 with an excess of LiBH 4 gave the yttrium borohydride complex [(C 5 H 4 CH 2 CH 2 OMe) 2 Y(μ-H) 2 BH 2 ] ( 3 ), whose crystal structure has been shown to be monomeric species with yttrium-coordinated ether functions and a η 2 -bonded borohydride ligand.