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 °C (specific surface area as: 500 m2g−1; mesopore volume Vp: 1.06 cm3g−1; main pore diameter: 85 Å). The bimetallic materials [Ln(AlEt4)2]@KIT-6−500 were analysed by DRIFT spectroscopy, elemental analysis, nitrogen physisorption and solid-state NMR. Upon heterogenization the surface area and pore volume of the KIT-6 materials dropped by 30–35% and 25%, respectively. The hybrid materials were compared to AlEt3@KIT-6−500 since reaction of AlEt3 with surface silanol groups is also a prominent reaction pathway when complexes [Ln(AlEt4)2]n are immobilized. Reaction of the Ln(II) tetraalkylaluminates with tris(tert-butoxy)silanol HOSi(OtBu)3 gave complexes Ln[(μ-OSi(OtBu)3)(μ-R)AlR2]2 (Ln = Yb, Sm; R = Et; Ln = Yb; R = Me) which can be seen as molecular model complexes, evidencing alkane elimination, trialkylaluminium adduct formation, and Ln(II)–O(siloxane) bonding.
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