Chiral bridged aminotroponiminate complexes of the lanthanides

Abstract

The enantiomerically pure bridged aminotroponimines, S,S- and R,R-H2{(iPrATI)2diph}, in which two amino-isopropyl-troponimine moieties are linked by 1,2-diamino-1,2-diphenylethane, were deprotonated with nBuLi to give the corresponding dilithium salts [{Li(THF)}2{(S,S)-(iPrATI)2diph)}] (1a) and [{Li(THF)}2{(R,R)-(iPrATI)2diph)}] (1b). The potassium salts [{K(THF)2}2{(S,S)-(iPrATI)2diph}] (2a) and [{K(THF)2}2{(R,R)-(iPrATI)2diph}] (2b) were obtained by a deprotonation reaction with KH. Transmetallation of 2a and 2b with anhydrous lanthanide trichlorides led to [(S,S)-{(iPrATI)2diph}LnCl(THF)] (Ln = Ho (3a), Er (4a)) and [(R,R)-{(iPrATI)2diph}LnCl(THF)] (Ln = Ho (3b), Er (4b), Yb (5b)), respectively. The corresponding Yb complex [(S,S)-{(iPrATI)2diph}YbCl(THF)] (5a) was obtained by treatment of 1a with YbCl3 at elevated temperature. Performing the same reaction at room temperature results in the metallate complex [(S,S)-{(iPrATI)2diph}YbCl2][Li(THF)4] (6). Reaction of NaC5H5 with afforded [(S,S)-{(iPrATI)2diph}Yb(eta5-C5H5)(THF)] (7). The structures of 1a, 3a, 4a, 5a, 5b, 6, and 7 were confirmed by single crystal X-ray diffraction in the solid-state.