Stable silylmethyl and neopentyl complexes of scandium(III) and yttrium(III)

Abstract

The complexes (Me,M'CH,),M*ZTHF (M = Sc The n.m.r. data are consistent with a trigonal bipyraniidal or Y ; M' = C or Si) and (o-MeOC,H,SiMe,CH,),Sc have arrangement of ligands around the metal, the THF molebeen isolated from the reaction of the appropriate cules occupying axial sites. The unusual five-co-ordination lithium reagent with MCI, or MC1;nTHF. may be favoured by the rather bulky Me,SiCH; ligands.

Rare Earth and Alkaline Earth Metal Complexes with Me2Si‐Bridged Cyclopentadienyl‐Imidazolin‐2‐Imine Ligands and Their Use as Constrained‐Geometry Hydroamination Catalysts

“…The 2-iminoimidazoline 1 and [Ln(CH 2 SiMe 3 ) 3 (THF) 2 ] (Ln = Sc, Y, Lu) were prepared according to published procedures. [3,40] [Ca(HMDS) 2 (THF) 2 ] was prepared from CaI 2 and NaN(SiMe 3 ) 2 according to a modified literature procedure; [27] a detailed protocol is given below. 5-(Chlorodimethylsilyl)-1,2,3,4-tetramethyl-1,3-cyclopentadiene (2) was purchased from Boulder Scientific Company and distilled prior to use.…”

Organometallic Compounds of the Lanthanides. 157 [1] The Molecular Structure of Tris(trimethylsilylmethyl)samarium, -erbium, -ytterbium, and -lutetium

“…Considerably less is reported on the 'small' monotrimethylsilyl ligand ϪCH 2 SiMe 3 [8]. Although the first tris(trimethylsilylmethyl) complexes of group 3 metals were already described almost 30 years ago [9], no detailed structural investigations have been carried das Sm Atom fac-oktaedrisch und die schweren Lanthanoide Er, Yb und Lu trigonal bipyramidal koordiniert mit den drei Alkylliganden in äquatorialer und zwei THF Molekülen in axialer Position. out yet.…”

“…Due to its minor steric requirement only base stabilized solvent-adducts can be obtained [2]. First experiments dealt with the light group 3 elements Sc and Y [9], whereas the bigger lanthanides up to Tb followed some years later [10,11]. Reaction conditions, solvents and solvent mixtures, respectively, as well as different alkylating agents in the system LnCl 3 / CH 2 SiMe 3 have been thoroughly examined in our group already (Ln ϭ La, Nd, Tb, Dy, Er, Tm, Yb, Lu) [12,13], but no solid state structures were determined, and whereas Sm[CH(SiMe 3 ) 2 ] 3 was obtained reacting a monomeric samarium aryloxide with three equivalents of LiCH-(SiMe 3 ) 2 [4], the attempt to synthesize Sm(CH 2 SiMe 3 ) 3 -(THF) 3 similarly by reaction of the aryloxide Sm(O-2,6-iPr 2 C 6 H 3 ) 3 (THF) 2 with three equivalents of LiCH 2 SiMe 3 failed.…”

Reversible Chain Transfer between Organoyttrium Cations and Aluminum: Synthesis of Aluminum‐Terminated Polyethylene with Extremely Narrow Molecular‐Weight Distribution

“…À in Isopar, DOW Chemicals), trimethylaluminum (TMA, 2.0 m in toluene, Aldrich), tri-isobutylaluminum (TIBA, 25 wt % in toluene, Aldrich), tri-n-octylaluminum (TOA, 25 wt % in toluene, Aldrich) and TIBA (Witco) were used as received. 2 ], [16] N,N-dimethylanilinium(tetraphenyl)borate [17] Preparation of 1 c: Compound B (2.75 g, 7.63 mmol), 1,3-bis(diphenylphosphino)propane (0.12 g, 0.28 mmol), tris(dibenzylideneacetone) dipalladium(0) (0.13 g, 0.14 mmol), and sodium tert-butoxide (0.83 g, 8.6 mmol) were loaded into a Schlenk tube. After adding 2,4,6-trimethylphenylamine (1.03 g, 7.63 mmol) in toluene (30 mL) the resulting mixture was heated at about 95 8C for 24 h. The reaction mixture was cooled to room temperature, and subsequently water (50 mL) and diethyl ether (50 mL) were added.…”