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MOF films for microsensor coatings

Materials Research Society Symposium Proceedings

Robinson, Alex; Allendorf, Mark; Stavila, Vitalie; Thornberg, Steve M.

Metal organic framework (MOF) materials are a class of hybrid organic-inorganic crystalline materials whose pore structures and chemical properties can be tailored by the selection of component chemical moieties. Many MOFs have extraordinary intrinsic surface areas, capable of adsorbing large quantities of other chemicals, such as volatile organic compounds or moisture. Upon absorption of guest molecules, many MOFs undergo reversible changes in the dimensions of their unit cells. These properties suggest several routes to chemical sensing in which the transduction mechanisms are: 1) the stress induced at an interface between a flexible MOF layer and a static microcantilever fabricated with a built-in piezoresistive stress sensor; 2) the change in the resonant frequency of an oscillating microcantilever induced by mass adsorption; and 3) the change in the resonant frequency of a acoustic sensor, such as a surface acoustic wave (SAW) sensor through changes in mass loading and film moduli. This paper focuses on humidity sensing by SAWs coated with Cu 3(BTC) 2 (HKUST-1) over a very broad concentration range. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. © 2011 Materials Research Society.

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Stereochemistry of lead(II) complexes with oxygen donor ligands

Proposed for publication in the Coordination Chemistry Reviews.

Stavila, Vitalie

This review discusses the coordination number (CN) and the coordination geometry of the first coordination sphere of Pb(II) atoms in crystal structures of 98 lead(II) complexes with O-donor ligands and the stereochemically active lone pair of electrons (LP, E) in the terms of the valence shell electron-pair repulsion (VSEPR) model. The CN of Pb(II) atoms of the first coordination sphere has values falling into the range (3 + E) to (6 + E). The following coordination polyhedra-{psi}-tetrahedron (I), {psi}-trigonal bipyramid (II), {psi}-octahedron (III), {psi}-pentagonal bipyramid with an axial (IV) or equatorial (V) vacant position are formed. For the investigated structures of the Pb(II) complexes, the formula of each compound, the overall CN of the Pb(II) atom considered as the sum of the CN in the first coordination sphere and the number of secondary bonds, the polyhedron shape, the Pb-O bond lengths, and O-Pb-O bond angles in the first coordination sphere, secondary bond lengths, references and REFCODEs are presented in the comprehensive Tables. The quantum chemical investigations performed using density functional theory (DFT) method have confirmed the stereochemical activity of the LP of Pb(II) atoms in the studied structures of lead(II) complexes with O-donor ligands.

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Results 201–225 of 226
Results 201–225 of 226