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172 results on '"Hampden-Smith, M. J."'

5. Low-temperature copper etching via reactions with Cl2 and PEt3 under ultrahigh vacuum conditions.

Author

Farkas, J., Chi, K.-M., Hampden-Smith, M. J., Kodas, T. T., and Dubois, L. H.

Subjects
COPPER absorption & adsorption, COPPER surfaces, ULTRAHIGH vacuum
Abstract

Presents information on a study which investigated the adsorption and desorption behavior of PEt[sub3] on copper and chlorinated copper surfaces under ultrahigh vacuum conditions. Experimental procedures; Results and discussion; Conclusion.

Published
1993
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6. Formation of copper patterns on poly(tetrafluoroethylene) via radiation controlled chemical etching and chemical-vapor deposition.

Author

Rye, R. R., Knapp, J. A., Chi, K.-M., Hampden-Smith, M. J., and Kodas, T. T.

Subjects
COPPER, RADIATION, SEMICONDUCTOR etching, CHEMICAL vapor deposition, THIN films
Abstract

Presents a study which described the formation of copper patterns on poly(tetrafluoroethylene) (PTFE) via radiation controlled chemical etching and chemical-vapor deposition. Process of the deposition of patterned copper films on poly(tetrafluoroethylene); Metal that has a low resistivity than copper; Factor that makes it difficult for PTFE to metallize; Use of copper films as Celerier and Machet point out.

Published
1992
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16. Hydrolysis and Condensation of Tin(IV) Alkoxide Compounds: The Control of Structural Evolution.

Author

NEW MEXICO UNIV ALBUQUERQUE DEPT OF CHEMISTRY, Hampden-Smith, M. J., NEW MEXICO UNIV ALBUQUERQUE DEPT OF CHEMISTRY, and Hampden-Smith, M. J.

Abstract

We have studied ester elimination in a number of model systems to determine the criteria which promote or inhibit such reactions. The model systems generally involve metal centers which possess NMR active nuclei such as 29Si, 119, 117Sn and 207Pb. In these systems, we have conducted a number of 170 labeling experiments which reveal that ester elimination is probably an associative process that requires electropositive metal alkoxide centers, accessible coordination sites at the metal centers, dangling carboxylate ligands and which is promoted by non- coordinating solvents and inhibited by coordinating solvents. In a heterobimetallic systems, the reaction between Sn(O-t-Bu)4 and Pb(OAc)4 results in formation of a metal oxo cluster in the presence of toluene. These metal oxo clusters retain their structure in solution as determined by multinuclear NMR spectroscopy for PbSn2O(O-t-Bu)4(OAc)4. As a result of this understanding gained from these model reactions, we are now in a position to investigate the formation of metal oxide materials using these clusters.

Published
1996

17. Hydrolysis and Condensation of Tin (IV) Alkoxide Compounds: The Control of Structural Evolution.

Author

NEW MEXICO UNIV ALBUQUERQUE DEPT OF CHEMISTRY, Hampden-Smith, M. J., NEW MEXICO UNIV ALBUQUERQUE DEPT OF CHEMISTRY, and Hampden-Smith, M. J.

Abstract

We are investigating the mechanism of ester elimination reactions between metal alkoxide compounds and metal carboxylate compounds as a method to form metal-oxo clusters in a controlled fashion. We anticipate that the fundamental insight gained will result in a better understanding of methods to control the evolution of microstructure in metal oxide ceramics. Two parts of our preliminary experiments are reported here. Part 1 describes a series of proton (1H) NMR magnetization transfer experiments utilized to measure the kinetic parameters of alcohol interchange between the homoleptic metal alkoxide, Sn(O-t-Bu)4, and t-butanol, its parent alcohol. These data suggest that the metal center, even in sterically encumbered metal alkoxide compounds such as Sn(O-t-Bu)4, are sufficiently coordinately and electronically unsaturated to react with bulky alcohols. These observations must be taken into account when conducting sol-gel type hydrolysis and condensation reactions. In part 2, the alkoxide Sn(O-t-Bu)4 and carboxylate Me3Si(OAc) are used in a detailed study of the ester elimination process. We report time dependent 170 NMR spectra of the ester elimination reaction of the two from which a plausible associative transition state can be described. Microstructure, Porosity, Tin oxide.

Published
1994

18. Formation of Highly Dispersed Metals Via Chemical Reduction Methods

Author

NEW MEXICO UNIV ALBUQUERQUE, Zeng, D., Hampden-Smith, M. J., Datye, A., NEW MEXICO UNIV ALBUQUERQUE, Zeng, D., Hampden-Smith, M. J., and Datye, A.

Abstract

A new reduction method for the preparation of the molybdenum halides MoCl3(THF)3 and MoCl4(THF)2 in high yield and with high purity directly from MoC15 is described. The preparation of pure starting materials is crucial to the success of the subsequent chemical reduction. Reduction of MoC13(THF)3, MoCl4(THF)2 or WCl4 in THF with LiBEt3H at room temperature did not result in formation of Mo and W as anticipated but instead resulted in formation of nanophase M2C M = MO and W binary metal carbides. These species were characterized by SEM, TEM, energy dispersive spectroscopy, electron diffraction, elemental analysis, thermogravimetric analysis and X-ray diffraction. These techniques showed the black solids were crystalline and comprised 1-2 nm sized crystallites which could be grown by heating to higher temperatures (450 - 500 deg C). The solids isolated from these experiments could be redispersed in THF to form colloidal black solutions.

Published
1992

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