Molecular rare earth metal alumosilicates.

The synthesis and stabilization of molecular four-coordinated lanthanide alumosilicates was achieved by the use of a highly encumbered alumosilicate ligand LAl(OH·thf)(μ-O)Si(OH)(OtBu)2 (1, L = HC{C(Me)N(2,6-iPr2C6H3)}2). Reactions between 1 and tris-cyclopentadienyl lanthanides (LnCp3; Ln = Ce, Nd, Sm, Gd, Tb, Dy, Y, Er) derived in the isolation of eight compounds (2-9) where the ligand is observed in three different bonding modes: adducts (2, 3), spirocyclic (4) or cyclic (5-9) coordination compounds. The observed reactivity can be related to the ionic radius of the lanthanide atom and the nature of the oxygen donor-atom from the hydroxide (Al-OH) or hydroxyl (Si-OH) moieties in 1. Compounds 2-9 present general O-Al-O-Si-O-Ln connectivities with different degrees of substitution over the -OH groups in 1 and structural features with only slight variations over the alumosilicate moiety (O-Al-O-Si-O) upon the lanthanide coordination. The spirocyclic samarium derivative presents two tetra-coordinated samarium atoms with a tetrahedral and distorted square planar geometries, respectively, as a result of a highly strained polycyclic architecture.