Synthesis and Reactivity of NNNNN-Pincer Multidentate Pyrrolyl Rare-Earth-Metal Amido-Chloride or Dialkyl Complexes

The NNNNN -pincer multidentate pyrrolyl rare-earth-metal amido-chloride complexes {η 1:κ 3 -2,5-[CH 3 N(CH 2 CH 2 ) 2 NCH 2 ] 2 C 4 H 2 N}RECl[N(SiMe 3 ) 2 ] (RE = Y ( 2a ), Sm ( 2b ), Dy ( 2c ), Er ( 2d ), Yb ( 2e )) were synthesized by one step from reactions of [(Me 3 Si) 2 N] 3 RE(μ-Cl)Li(THF) 3 with {2,5-[CH 3 N(CH 2 CH 2 ) 2 NCH 2 ] 2 }C 4 H 2 NH ( 1 ). Reactions of compound 1 with RE(CH 2 SiMe 3 ) 3 (THF) 2 gave the rare-earth-metal dialkyl complexes {η 1:κ 2 -2,5-[CH 3 N(CH 2 CH 2 ) 2 NCH 2 ] 2 C 4 H 2 N}Sc(CH 2 SiMe 3 ) 2 ( 3a ) and {η 1:κ 3 -2,5-[CH 3 N(CH 2 CH 2 ) 2 NCH 2 ] 2 C 4 H 2 N}RE(CH 2 SiMe 3 ) 2 (RE = Y ( 3b ), Dy ( 3c ), Er ( 3d ), Yb ( 3e ), Lu ( 3f )). Further reactions of complexes 3 with dimethylaniline afforded rare-earth-metal diamido complexes bearing an NNNNN -pincer multidentate pyrrolyl ligand, but not rare-earth-metal imido complexes even under the condition of additional DMAP. All complexes were characterized by spectroscopic methods, elemental analyses, and single-crystal X-ray diffraction. The pincer multidentate pyrrolyl rare-earth-metal dialkyl complexes showed high catalytic activities for the addition of amines to carbodiimides or isothiocyanate to afford the substituted guanidines and thioureas.