Reactivity of Binuclear Tantalum Clusters on Silica: Characterization by Transient Time-Resolved Spectroscopy

Journal Article · Thu May 08 04:00:00 EDT 2008 · J. Phys. Chem. C

DOI:https://doi.org/10.1021/jp074910f· OSTI ID:1018546

Nemana, Sailendra; Sun, Junming; Gates, Bruce C ^[1]

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1. UCD

Binuclear tantalum clusters were synthesized from Ta(CH{sub 2}Ph){sub 5} (Ph is phenyl) on the surface of nonporous SiO{sub 2} (Aerosil), and their reactions with H{sub 2}, D{sub 2}, and ethylene were characterized by time-resolved infrared (IR), extended X-ray absorption fine structure (EXAFS), and X-ray absorption near edge spectroscopies. The EXAFS data indicate the formation in H{sub 2} of clusters with a Ta-Ta coordination number of approximately 1 and a bonding distance of 2.74 {angstrom}. Reactions of the supported clusters with D{sub 2} and H{sub 2} facilitate the interconversion of O-H and O-D groups on the SiO{sub 2} surface. Reaction of these clusters with ethylene led to their rapid fragmentation to give mononuclear tantalum complexes, as the tantalum was oxidized and new ligands formed, suggested by IR spectra to be ethyl. The results demonstrate a rough analogy between the chemistry of tantalum clusters on the SiO{sub 2} surface and their chemistry in solution. Because alkenes are suggested intermediates in the catalytic disproportionation of alkanes on supported tantalum, our results indicate how these intermediates might influence the nature of the catalytically active species.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE Office of Science (SC)
• OSTI ID: 1018546
• Journal Information: J. Phys. Chem. C, Journal Name: J. Phys. Chem. C Journal Issue: (19) ; 2008 Vol. 112; ISSN 1932-7447
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION
ALKANES
ALKENES
BONDING
CHEMISTRY
COORDINATION NUMBER
ETHYLENE
FINE STRUCTURE
FRAGMENTATION
OXIDATION
REDUCTION
SILICA
SPECTRA
SPECTROSCOPY
TANTALUM
TANTALUM COMPLEXES
TRANSIENTS