Metal-organic gels as functionalisable supports for catalysis

Modification of Fe-tricarboxylate based metal-organic gels yielded tert-butyl substituted or phosphine-functionalised gels in alcohols or DMF, which were prepared from 5-tert-butylisophthalic acid and 5-diphenylphosphanylisophthalic acid, respectively. Owing to their permeability, such phosphine-functionalised metal-organic gels can act as a new type of functionalisable porous scaffold. The phosphorus-containing gel was subsequently functionalised with Pd(II) by immersion in a solution of Pd(COD)Cl-2 (COD = 1,5-cyclooctadiene). The subsequently functionalised Pd(II)-immobilised gel and its xerogel/aerogel showed high activity in the catalysis of Suzuki C-C coupling comparable to unsupported complexes. The gel/xerogels could be reused under ambient atmosphere.