Lanthanoid Pseudo‐Grignard Reagents: A Major Untapped Resource

Abstract

Pseudo-Grignardr eagents PhLnI (Ln = Yb, Eu), readily prepared by the oxidative addition of iodobenzene to ytterbium or europium metal at À78 8Cint etrahydrofuran (THF) or 1,2-dimethoxyethane (DME), react with ar ange of bulky N,N'-bis(aryl)formamidines to generate an extensive series of Ln II or more rarely Ln III complexes,n amely [Eu(Dipp-, and [Yb(XylForm) 2 I(dme)]·dme (7b){ (Form = ArNCHNAr;X ylForm (Ar = 2,6-Me 2 C 6 H 3 ), MesForm (Ar = 2,4,6-Me 3 C 6 H 2 ), DippForm (Ar = 2,6-iPr 2 C 6 H 3 )}. Reaction of PhEuI and MesFormH in DME consistently gave 2, and reactionw ith XylFormH in THF gave 4.E uropium complexes 1 and 3a are seven-coordinate divalent monomers, whilst 3b is as even-coordinate dme-bridged polymer.C omplex 5a of the smaller Yb II is as ix-coordinate monomer,b ut the related 6 and 7a are six-coordinatei odide-bridged dimers. 4 is at rivalent seven-coordinate hydroxide-bridged dimer,w hereas complexes 5b and 7b are seven-coordinate monomeric Yb III derivatives. Ac haracteristic structural feature is that iodide ligands are cisoid to the formamidinate ligand.T oi llustrate the synthetic scope of the pseudoGrignardr eagents,[ Yb(Ph 2 pz)I(thf) 4 ]( Ph 2 pz = 3,5-diphenylpyrazolate) was oxidised with 1,2-diiodoethane to afford seven-coordinate monomeric pyrazolato-ytterbium (III)

A Deca‐9‐Fluorenolato‐deca‐Samarium Oxide Cage

“…Comparisons between 2 and 6 shows that 2 has slightly longer metal–ligand bond lengths than 6 (Figure ), but the larger difference in Yb–I bond lengths is attributable to a change from terminal Yb–I in 6 to bridging in 2 . The bond lengths are similar to those of other iodide bridged formamidinatoytterbium(II) complexes …”

“…The other product obtained from the reaction between [Yb(DippForm) 2 (fn · ‐O)(thf)] and SmI 2 (thf) 2 was dichroic green/yellow crystals of [Yb(DippForm)(µ‐I)(thf) 2 ] 2 ( 2 ). We recently reported the monomeric derivative of 2 , namely [YbI(DippForm)(thf) 3 ] ( 6 ), which was crystallized from THF as orange crystals . It is likely that the dimeric form ( 2 ) is obtained from the removal of THF from the coordination sphere of Yb by toluene, a common occurrence in rare‐earth formamidinate chemistry .…”

Crystal structure of the [(THF)Cs(μ-η5:η5-Cp′)3Yb] n oligomer

“…A survey of the Cambridge Structural Database (CSD, version 5.41, March 2020; Groom et al, 2016) also revealed four oligomeric complexes containing Yb-Cp x moieties with various types of cyclopentadienyl rings (Cp x ): [Na(-5 : 5 -C 5 H 5 ) 3 Yb II ] n (Apostolidis et al, 1997), [Na(-5 : 5 -Cp 00 ) 2 Yb II 2 (-5 : 5 -Cp 00 ) 2 ] n (Voskoboynikov et al, 1997), [(C 5 Me 5 )Yb(-I)(-5 : 5 -C 5 Me 5 )Yb(C 5 Me 5 )] n (Evans et al, 2006) and [Yb(-5 : 5 -C 5 H 5 )(Ph 2 Pz)(THF)] n (Ph 2 Pz = 3,5diphenylpyrazolate) (Ali et al, 2018). The [Na(-5 : 5 -C 5 H 5 ) 3 Yb II ] n (Apostolidis et al, 1997) complex adopts a hexagonal net extended structure similar to that in 1 except the alkali metal does not have a coordinated solvent.…”

Synthesis, Characterization, and Catalytic Activity of Dinuclear Rare-Earth Metal Alkyl Complexes Bearing 2,6-Diisopropylphenylamidomethyl Functionalized Pyrrolyl Ligand

“…Thus, the development of an appropriate ancillary ligand to stabilize bimetallic rare-earth metal complexes is of great importance. Among the reported studies, considerable attention has been directed toward the bridged bimetallic complexes, such as rare-earth metal chlorides, hydrides, carbon-bridged, and heteroatom-bridged bimetallic complexes. Both dinuclear silylene-linked cyclopentadienyl-phosphido rare-earth metal alkyl complexes and dinuclear rare-earth metal amidinate complexes show high 3,4-selectivity in the polymerization of isoprene.…”