Phosphinomethanid-komplexe der lanthanoide

Abstract By reaction of LnI 2 · 2THF, Ln  Yb, Sm with the phosphinomethanides Li[C(PMe 2 ) 2 X], X  SiMe 3 , PMe 2 the addition products {(THF)Ln[C(PMe 2 ) 2 X] 2 I 2 Li(THF)}, Ln  Yb, X  SiMe 3 ( 1a ), X  PMe 2 ( 1b ) and Ln  Sm, X  SiMe 3 ( 2 ) are obtained; 1a could be characterized by X-ray crystal structure analysis. In contrast complete substitution is achieved in the reaction of lanthanide triflates with lithium phosphinomethanides. Thus the seven-coordinated and X-ray structurally characterized complex {(THF)Lu[C(PMe 2 ) 2 (SiMe 3 )] 3 } ( 3 ) is obtained. Lu[C(PMe 2 ) 2 (SiMe 3 )] 3 ( 4 ) could be obtained from 3 by removing thf in vacuo or by reaction of Lu(CF 3 SO 3 ) 3 with Li[C(PMe 2 ) 2 (SiMe 3 )] in toluene. The derivative {(THF)Lu(Me)[C(PMe 2 ) 2 (SiMe 3 )] 2 } ( 5 ) has been isolated by treatment of 3 with LiMe. In a somewhat random way, one run with LiMe gave the X-ray structurally characterized, anionic complex [(THF) 4 Li]{Lu(OSiMe 3 )[CPMe 2 ) 2 (SiMe 3 )] 3 } ( 6 ) obviously by cleavage of silicon grease. A coordination number of eight is observed in the anionic complexes {Ln[C(PMe 2 ) 2 (SiMe 3 )] 4 Li}, Ln  Er ( 7 ), Y ( 8 ) und La ( 9 ). The X-ray crystal structure of 9 verifies the new type of an eightfold phosphorus coordinated lanthanoid center. In compounds Sc[C(PMe 2 ) 2 X)] 3 , X  SiMe 3 ( 10a ) and X  PMe 2 ( 10b ) the phosphino-methanide ligands are arranged in an intermediate coordination mode between σ-chelating and π-type coordination as revealed by X-ray diffraction. The X-ray structurally characterized dimeric complex {Sm[CH(PMe 2 ) 2 ] 3 } 2 ( 11 ) combines two different phosphinomethanide coordination modes. Two phosphinomethanide ligands in 11 ) adopt a π-type coordination, the third ligand is arranged in a η 2 , μ-C,P fashion.