title: Directed-sorting method for synthesis of bead-based combinatorial libraries of heterogeneous catalysts.
abstract: The synthesis and analysis of inorganic material combinatorial libraries by a directed-sorting, split-pool bead method was demonstrated. Directed-sorting, split-pool, metal-loaded libraries were synthesized by adsorbing metal salts (H2PtCl6, SnCl2, CuCl2, and NiCl2) and metal standards (Pt, Cu, Ni in HCl) onto 2-mg porous gamma-alumina beads in 96- or 384-well plates. A matrix algorithm for the synthesis of bead libraries treated each bead as a member of a row or column of a given matrix. Computer simulations and manual tracking of the sorting process were used to assess library diversity. The bead compositions were analyzed by energy-dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy, electron probe microanalysis, inductively coupled plasma atomic emission spectroscopy, and inductively coupled plasma mass spectroscopy. The metal-loaded beads were analyzed by laser-activated membrane introduction mass spectroscopy (LAMIMS) for catalytic activity using methylcyclohexane dehydrogenation to toluene as a probe reaction. The catalytic activity of individual beads that showed minimal (approximately 20% of that of Pt on alumina) to high conversion could be determined semiquantitatively by LAMIMS. This method, therefore, provides an alternative to screening using microreactors for reactors that employ catalysts in the form of beads. The directed-sorting method offers the potential for synthesis of focused libraries of inorganic materials through relatively simple benchtop split-pool chemistry.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Ramanathan
authors.initials: R
authors.lastname: Ramnarayanan
authors.forename: Benny C
authors.initials: BC
authors.lastname: Chan
authors.forename: Michael A
authors.initials: MA
authors.lastname: Salvitti
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Mallouk
authors.forename: Falaah M
authors.initials: FM
authors.lastname: Falih
authors.forename: Jason
authors.initials: J
authors.lastname: Davis
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Galloway
authors.forename: Simon R
authors.initials: SR
authors.lastname: Bare
authors.forename: Richard R
authors.initials: RR
authors.lastname: Willis
mesh_terms: D002384:Catalysis; D002712:Chlorides; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D003198:Computer Simulation; D008670:Metals; D014618:Vacuum
chemical_list: D002712:Chlorides; D008670:Metals