Mesoporous organosilicas with Pd(II) complexes in their framework

Abstract

Incorporation of various Pd(II) complexes into the framework of mesoporous organosilica materials has been achieved by co-condensation, using a facile solvent-free one-pot method. The synthesis of Pd(II) complexes using ligands with triethoxysilyl terminal groups allowed for their homogeneous in situ incorporation into the organosiliceous structure. Organic/inorganic precursor bis(triethoxysilyl)ethane was used both, as silica source and as solvent for the synthesis of the complexes, avoiding the use of any other organic co-solvent and making the synthesis more environmentally friendly. The mild synthetic conditions used such as neutral pH, room temperature and ethanol extraction of the surfactant, allowed for a cleaner route for the preparation of hybrid organic/inorganic mesoporous materials with Pd(II) complexes covalently bounded to the support. The chemical integrity of the metal complexes after the synthesis of the hybrid material, [trans-PdCl2L2] (L=4-C5H4N-(CH2)2Si(OEt3) and PPh2(CH2)2Si(OEt)3), was confirmed by several spectroscopic techniques. A systematic study of the role of the different parameters involved in the synthesis of these materials and their relation with the final morphology of the catalysts is herein described.