Synthesis and characterization of organocyclophosphazene–silica composites: new materials able to retain metal complexes

Abstract

The organocyclotriphosphazenes P₃N₃[N(CH₃)(CH₂)₂CN]₆ (1), P₃N₃[OC₆H₄CN]₆ (2) and P₃N₃[OC₆H₄CH₂CN]₆ (3) were synthesized and encapsulated in a silica matrix via a sol–gel process, affording new transparent hybrid materials of composition phosphazene/(SiO₂)_n. These materials were characterized by elemental analysis, IR, ¹³C, ³¹P and ²⁹Si MAS-NMR spectroscopy, TG/DSC, SEM and TEM microscopy as well as by XPS. The composites containing the phosphazenes (1) and (3) are able to retain various metallic complexes such as iron and cobalt complexes at trace levels (ng mL⁻¹) by using 2,4,6-tripyridyl-1,3,5-triazine (TPTZ) and 1,2-pyridylazo-2-naphthol (PAN) as ligands. Some analytical applications are given.