Soluble alumotitanosilicates and their zirconium and hafnium analogues

Abstract

The synthesis of molecular heterometallic alumosilicates in good yields has been achieved by reaction between LAl(OH·thf)(μ-O)Si(OH)(OtBu) 2 (1, L = [HC{C(Me)N(Ar)}2]-, Ar = 2,6-iPr 2C6H3) and group 4 amides. These reactions lead to inorganic cycles (type I) and spirocycles (type II) containing six-membered rings with unprecedented inorganic cores (O-Al-O-Si-O)nM (n = 1, 2; M = Ti, Zr and Hf). Noteworthy, for the heavier metals, Zr and Hf, higher steric bulk in the alkyl substituent of the amide moiety is required to obtain type I compounds. The solid-state structures for all compounds were determined and reveal a tetrahedral environment for all metal atoms, dihedral angles close to 90° for spirocyclic compounds, and isomorphous structures for the Zr and Hf derivatives. Unprecedented molecular heterobimetallic alumosilicates with inorganic cores O-Al-O-Si-O-M or (O-Al-O-Si-O)2M (M = Ti, Zr, Hf) have been prepared by reaction of the molecular alumosilicate LAl(OH)(μ-O)Si(OH)(OtBu)2 (L = [HC{C(Me)N(Ar)}2] -, Ar = 2,6-iPr2C6H3) with group 4 metal amides in different ratios. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.