Terminal dysprosium and holmium organoimides

Abstract

Terminal rare-earth-metal imide complexes TptBu,MeLn(NC6H3iPr2‑2,6)(dmap) of the mid-late rare-earth elements dysprosium and holmium were synthesized via double methane elimination of Lewis acid stabilized dialkyl precursors TptBu,MeLnMe(GaMe4) with primary aniline derivative...

Rare-Earth-Metal Methyl and Methylidene Complexes Stabilized by TpR,R′-Scorpionato Ligands─Size Matters

“…The tetramethylaluminato ligands coordinate differently, one in the routinely observed planar η 2 mode (Ln1–C5–Al2–C6: 6-Y , 14.93(8)°; 6-Lu , 11.47(8)°), and the other in an η 1 fashion. The η 1 -coordination with almost linear Ln–C­(μ-CH 3 )–Al bond angles has been detected before in (Tp t Bu,Me )­Ln­(CH 3 )­[(μ-CH 3 )­EMe 3 ] (E = Al, Ga). ,, The respective Ln–C­(μ-CH 3 ) distances match that found in 5-Y (2.715(3) Å), and also the Ln–C distances involving the η 2 -coordinated AlMe 4 ligands lie well within the range observed for Ln­(AlMe 4 ) 3 ( 1-Y , av. 2.508 Å; 1-Lu , av.…”

“…The structural features of the six-coordinate yttrium complex 11-Y are similar to those found in complexes 10-Ln (Scheme ). Striking is that one pyrazolyl moiety of the tridentate Tp t Bu,Me ligand is tilted toward the metal center, resulting in another close Y···N contact. The coordination sphere is completed by one η 2 -pyrazolyl ligand and the η 1 -GaMe 4 moiety.…”

“…The solid-state structures of 6-Y and 6-Lu could unequivocally be determined by SC-XRD analysis, revealing isostructural species (Figures and S2, Table ). Strikingly, in comparison to the 5-coordinate complexes (Tp t Bu,Me )­LnMe­[(μ-Me)­AlMe 3 ] ( 5-Ln ; Scheme ) ,, supported by the larger scorpionato ligand, complexes 6-Ln display 6-coordinate Ln­(III) centers. Their coordination geometry is best described as distorted octahedral with N2 and C5 occupying the axial positions and N4, N6, C1, and C6 in the equatorial plane.…”

“…We also reported that the protonolysis of Ln­(GaMe 4 ) 3 with HTp t Bu,Me involving the larger yttrium and holmium gave complexes (Tp t Bu,Me )­LnMe­[(μ-Me)­GaMe 3 ] ( 10-Ln , Ln = Y, Ho, Scheme ). Compounds 10-Ln precipitated from n -hexane only in moderate yield, which is why we examined the n -hexane solution more closely. Cooling of the n -hexane extracts at −35 °C yielded colorless crystals of 12 and led to precipitation of 11-Ln .…”

“…Following the procedure described for the synthesis of compound 10-Ln , the supernatant and n -hexane extracts were combined, and the title compound was precipitated in the cold (−35 °C) and dried under vacuum.…”