We have been studying the covalent binding of luminescent and catalytically active transition metal complexes to silica polyamine composites (SPC) with a view towards applications in metal sensing and catalysis. In the case of the luminescent Ru complexes, Ru(CO)(H)(L2)(L’2)][PF6], (L2=trans-2PPh3, L’=η2-4,4’-dicarboxy-bipyridine L2=trans-2Ph2PCH2CH2COOH, L’2=bipyridine ; L2=Ph2PCHCHPPh2)(L’= η2-5-amino-1,10-phenanthroline ; L2= trans-2PPh3, L’2=η2-4-carboxaldehyde-4’-methyl-bipyridine)(1) binding to the composite surface results in significant increases in excited state lifetime, whose magnitude is dependent on the nature of the surface and the size of the silica particle to which they are bound (micro- versus nano-particles).1 When metal ions in aqueous in solution are exposed to these surfaces quenching or enhancement of the luminescence is observed that is dependent on the type of metal ion and sensitive to the binding constant of the metal to the composite surface (2). In a separate study of the binding of the PNN pincer complexes of ruthenium, (C6H3NCH2P(t-butyl)2)N(Et)2Ru(H)(CO)Cl (3), bound to the composite surface. We observed catalytic dehydrogenation of alcohols to give esters, a reaction that usually requires the addition of strong base. Here the polyamine surface provides the necessary basic environment, and the immobilization allows for reuse of the catalyst for 4-5 cycles. Details and directions for the future will be presented.

Immobilization of transition metal complexes on composite surfaces: Metal sensing and catalysis

251st National Meeting (2016)

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