ACS Meeting
Joint 55th Southwest/15th Rocky Mountain Regional Meeting
El Paso, Texas
October 21-23, 1999
 
Barron Research Group
Abstracts

UTILIZATION OF THE tert-BUTYL GALLIUM TELLURIDE CUBANE AS A REDUCING AGENT
Bradley D. Fahlman and Andrew R. Barron, Department of Chemistry, Houston, Texas, 77005

The room temperature reactivity of [(tBu)GaTe]4 with selenium dioxide, sulfur dioxide, sulfur trioxide, molecular oxygen and sodium cyclopentadienyl will be discussed. Comparisons to previous work investigating the reactions between the telluride cubane and elemental sulfur and selenium will also be provided. In all cases, the evidence of tellurium metal deposited during the reactions was confirmed by microprobe analyses. The products were characterized by NMR spectroscopy and mass spectrometry. A rationale for the facile nature of these types of reactions will be discussed.

A NOVEL METHOD TO PRODUCE MOLYBDENUM OXIDE SUPPORTED ON HIGH SURFACE AREA ALUMINA FOR HETEROGENOUS CATALYSIS
Christopher D. Jones (a) Andrew R. Barron (a,b), (a) Department of Chemistry (b) Department of Mechanical Engineering and Materials Science, Rice Universtiy, Houston, TX, 77005

Carboxylate-alumoxanes are organic substituted alumina nano-particles synthesized from boehmite in aqueous solution which are an inexpensive and environmentally-benign precursor for the fabrication of nano, meso, and macro scale aluminum based ceramic membranes. One application of this material is the solid support for heterogeneous catalysis. To investigate this area, molybdenum oxide was reacted with gluconoto-alumoxane to produce molybdenum oxide supported on a high surface area alumina. This is a departure from traditional sol-gel methods. The purpose of this investigation will focus on understanding the nature of the active site. Characterization of the active site that will be discussed will include NMR, IR, XPS, EDX, BET, XRID and TGA/DTA analysis of the precursor and the final calcined material.

SOLUTION CHEMISTRY OF GALLIUM SULFIDE CUBANES.
Thomas J. Barbarich,a Andrew R. Barron.b a Department of Chemistry, Rice University, Houston, TX, 77005. b Department of Chemistry and Departments of Mechanical Engineering and Materials Science.

The interest in single-source precursor routes to thin conducting films of Group 13 chalcogenides led to the synthesis of the volatile solids [(R)Ga(m-S)]4 (R = Me3C, Et2MeC, Me2EtC). While the MOCVD of [(R)Ga(m-S)]4 produces a GaS cubic phase with a structure reminiscent of the cubane core, there are a number of drawbacks with respect to their ready use as a commercial precursor. This presentation will describe the solution chemistry of these compounds, with special emphasis placed upon the development of new single-source precursors.

EPOXY RESIN MATERIALS USING FUNCTIONALIZED CARBOXYLATE-ALUMOXANES AS CROSS-LINKING AGENTS
Cullen T. Vogelson, Simon G. Bott, and Andrew R. Barron, Department of Chemistry, Rice University, Houston, Texas, 77005 and Department of Chemistry, University of Houston, Houston, Texas 77204
 
We report that p-hydroxybenzoate or lysine substituted alumoxanes are readily prepared from the reaction of boehmite, [AlO(OH)]n, with the parent acid and that the particle size of these alumoxanes is pH controlled. The surface hydroxides and amines of the alumoxanes then react with commerically available epoxy resin-hardener systems to give a new class of inorganic-organic composite material. The physical properties of these composite materials may be directed by the choice of alumoxane, particle size, and resin/hardener system. The resulting materials can then be molded or shaped as desired with minimal shrinkage and improved cure times/temperatures. Details of the process will be presented along with the corresponding physical properties, solid state NMR characterizations, and X-Ray crystallographic data for several model systems.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF CYCLOPENTADIENYLIRON- AND CYCLOPENTADIENYLMOLYBDENUM-GALLIUM COMPOUNDS. A.S. Borovik, S.G. Bott, and A.R. Barron, Department of Chemistry, Rice University, Houston, Texas 77005 and Department of Chemistry, University of Houston, TX, 77204

Reaction of K[CpFe(CO)2] with a large excess of GaCl3 yields [{CpFe(CO)2}Ga(Cl.GaCl3)(m-Cl)]2 (1), while reactions with 1 and 0.5 equivalents yields [{CpFe(CO)2}GaCl2]n (2), and [{CpFe(CO)2}2Ga(m-Cl)] (3), respectively. Compound 2 reacts with MeCN to yield [CpFe(CO)2]GaCl2(MeCN). Reduction of compound 3 with potassium in Et2O yields the previously reported [CpFe(CO)2]3Ga and gallium metal. Reaction of K[CpFe(CO)2] with GaI3 yields [CpFe(CO)2]GaI2, which upon hydrolysis gives the unusual galloxane, [CpFe(CO)2]6Ga6(m3-O)4(m-OH)2I2 (4). Reaction of CpMo(CO)3H with Ga(tBu)3 yields [CpMo(CO)3]Ga(tBu)2 (5). The structure of compound 5 shows evidence of unusual carbonyl...gallium interactions. The structures of compounds 1, 3, 4.Et2O, and 5 have been determined by X-ray crystallography.

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