Yttrium and Lanthanide Complexes Having a Chiral Phosphanylamide in the Coordination Sphere

The chiral phosphanylamides {N(R-*CHMePh)(PPh2)}- and {N(S-*CHMePh)(PPh2)}- were introduced into rare
earth chemistry. Transmetalation of the enantiomeric pure lithium compounds Li{N(R-*CHMePh)(PPh2)} (1a) and
Li{N(S-*CHMePh)(PPh2)} (1b) with lanthanide bis(phosphinimino)methanide dichloride [{CH(PPh2NSiMe3)2}LnCl2]2
in a 2:1 molar ratio in THF afforded the enantiomeric pure complexes [{CH(PPh2NSiMe3)2}Ln(Cl){η2-N(R-*CHMePh)(PPh2)}] (Ln = Er (2a), Yb (3a), Lu (4a)) and [{CH(PPh2NSiMe3)2}Ln(Cl){η2-N(S-*CHMePh)(PPh2)}] (Ln = Er
(2b), Yb (3b), Lu (4b)). The solid-state structures of 2a and 3a,b were established by single-crystal X-ray diffraction.
Attempts to synthesize compounds 3 in a one-pot reaction starting from K{CH(PPh2NSiMe3)2}, YbCl3, and 1 resulted
in the lithium chloride incorporated complex [{(Me3SiNPPh2)2CH}Yb(μ-Cl)2LiCl(THF)2] (5). In an alternative approach
to give chiral rare earth compounds in a one-pot reaction 1a or 1b was reacted with LnCl3 and K2C8H8 to give the
enantiomeric pure cyclooctatetraene compounds [{η2-N(R-*CHMePh)(PPh2)}Ln(η8-C8H8)] (Ln = Y (6a), Er (7a),
Yb (8)) and [{η2-N(S-*CHMePh)(PPh2)}Ln(η8-C8H8)] (Ln = Y (6b), Er (7b)). The structures of 6a,b, 7a, and 8
were confirmed by single-crystal X-ray diffraction in the solid state.