Dinuclear Chlorido‐, Alkyl(chlorido)‐, and Hydridoyttrium Complexes Supported by μ‐Bridging‐Silyl‐Linked Bis(amidinate) Ligands

Abstract

AbstractA chloridoyttrium complex supported by a silyl‐linked bis(amidinate) ligand, [(Me2Si{NC(Ph)N(2,6‐iPr2–C6H3)}2)2(YCl)2(μ‐Cl)]–[Li(thf)4]+ (2) (thf = tetrahydrofuran), was synthesized by the reaction of equimolar amounts of anhydrous YCl3 and lithium amidinate [(Me2Si{NC(Ph)N(2,6‐iPr2–C6H3)}2)2Li3]–[Li(thf)4]+ (1) in thf at 20 °C. Complex 2 was isolated after recrystallization from a thf/hexane mixture in 72 % yield. Single‐crystal X‐ray structure analysis has revealed that 2 is a dinuclear compound composed of a discrete complex anion [(Me2Si{NC(Ph)N(2,6‐iPr2–C6H3)}2)2(YCl)2(μ‐Cl)]–, containing one μ‐bridging and two terminal chloride ligands, and a cation [Li(thf)4]+. The formation of a dimeric structure results from the coordination of amidinate fragments of the same dianionic ligand on two different yttrium ions and the presence of a μ‐bridging chloride ligand. Alkylation of 2 with one equivalent of Me3SiCH2Li in toluene afforded an alkyl(chlorido)yttrium complex, [Me2Si{NC(Ph)N(2,6‐iPr2–C6H3)}2]2[Y(thf)](μ‐Cl)[Y(CH2SiMe3)] (3). X‐ray crystal structure investigation has shown that 3 is a dimeric complex as a result of the “spanning” coordination mode of the ansa‐bis(amidinate) ligands and the presence of one μ2‐chloride ligand, while the alkyl group remains terminal. Treatment of the in situ generated alkyl derivative [Me2Si{NC(Ph)N(2,6‐iPr2–C6H3)}2]2[Y(CH2SiMe3)]2 (4) with PhSiH3 in toluene results in the formation of the corresponding hydridoyttrium complex [Me2Si{NC(Ph)N(2,6‐iPr2–C6H3)}2Y(μ‐H)]2 (5), which was isolated after recrystallization from toluene in 73 % yield. According to the X‐ray crystal structure analysis, 5 adopts a dimeric structure with two μ‐bridging bis(amidinate) and two μ2‐hydrido ligands.