Grafting of peralkylated Ln(II)Al(III) heterobimetallic complexes onto periodic mesoporous silica KIT-6.

Tetraethylaluminates of the divalent lanthanides ytterbium and samarium were grafted onto large-pore cubic periodic mesoporous silica (PMS) KIT-6, which had been dehydroxylated at 500 degrees C (specific surface area a(s): 500 m(2)g(-1); mesopore volume V(p): 1.06 cm(3)g(-1); main pore diameter: 85 A). The bimetallic materials [Ln(AlEt(4))(2)]@KIT-6(-500) were analysed by DRIFT spectroscopy, elemental analysis, nitrogen physisorption and solid-state NMR.

Distinct reaction pathways of peralkylated LnIIAlIII heterobimetallic complexes with substituted phenols.

The protonolysis reaction of heterobimetallic peralkylated complexes [Ln(AlR4)2]n (Ln=Sm, Yb; R=Me, Et) with 2 equiv of HOC 6H 2 tBu 2-2,6-Me-4 affords the bis(trialkylaluminum) adducts Ln[(micro-OArtBu,Me)(micro-R)AlR2]2 in good yields. Analogous reactions with the less sterically demanding iPr-substituted phenol result in ligand redistributions and formation of X-ray structurally evidenced Ln[(micro-OAriPr,H) 2AlR2]2 (Ln=Yb, R=Me; Ln=Sm, R=Et), Yb[(micro-OAriPr,H)(micro-Et)AlEt2]2(THF), and [Et2Al(micro-OAriPr,H) 2Yb(micro-Et)2AlEt2]2. The solid-state structures of serendipitous alumoxane complex Sm[(micro-OArtBu,Me)AlEt2OAlEt2(micro-OArtBu,Me)](toluene) and dimeric AlMe 3-adduct complex [(AlMe3)(micro-OArtBu,Me)Sm(micro-OArtBu,Me) 2Sm(micro-OArtBu,Me)(AlMe3)] were also determined by X-ray crystallography.

Characterization and reactivity of peralkylated LnIIAlIII heterobimetallic complexes.

The heterobimetallic peralkylated complexes [Ln(AlR4)2]n (Ln = Sm, Yb; R = Me, Et) were synthesized by a silylamide elimination route from Ln[N(SiMe3)2]2(THF)2 and an excess of AlR3. The solid-state structure of [Sm(AlEt4)2]n is isomorphous to that of the ytterbium derivative. Polymeric [Yb(AlMe4)2]n was examined by 1H and 13C MAS NMR spectroscopy revealing the presence of distinct bridging methyl groups.