Characterization of decaosmium carbido carbonyl clusters supported on MgO
Journal Article
·
· Journal of Physical Chemistry
- North Carolina State Univ., Raleigh, NC (United States)
- Univ. of Delaware, Newark, DE (United States)
Supported decaosmium carbido carbonyl clusters were prepared by surface-mediated organometallic synthesis from chloroosmium complexes on MgO and by adsorption of [Os{sub 10}C(CO){sub 24}]{sup 2-} onto thermally activated MgO from THF solution. The supported clusters have been characterized by extended X-ray absorption fine structure (EXAFS) spectroscopy, ultraviolet-visible diffuse reflectance (UV-vis DR) spectroscopy, and infrared spectroscopy. Transmission electron microscope (TEM) images of clusters prepared by surface-mediated synthesis have been obtained. Analysis of the Os L{sub III} EXAFS data indicates that each preparation yields molecularly dispersed {open_quotes}[Os{sub 10}C(CO){sub 24}]{close_quotes} clusters with structures closely similar to that of the dianion in crystalline [Et{sub 4}N]{sub 2}[Os{sub 10}C(CO){sub 24}]. The principal optical absorption of the supported clusters can be assigned to an Os-Os*{yields}CO{open_quotes}2{pi}*{close_quotes} transition by comparison to the UV-vis spectrum of [PPN]{sub 2}[Os{sub 10}C(CO){sub 24}] in solution. Infrared spectra provide evidence of {open_quotes}Os{sub 10}C(CO){sub 24}]{close_quotes} clusters in oxidized and reduced states (relative to the dianion) on the MgO surfaces. Apparently, surface, mediated synthesis yields [Os{sub 10}C(CO){sub 24}]{sup n-}, n = 0, 1, and 2; and adsorption of [Os{sub 10}C(CO){sub 24}]{sup 2-} onto MgO yields [Os{sub 10}C(CO){sub 24}{sup n-}, n = 2, 3, and 4. TEM images of supported clusters prepared by surface-mediated synthesis contain high-contrast scattering centers about 10 {angstrom} in size that are inferred to be decaosmium species. 32 refs., 7 figs., 3 tabs.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 379459
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 3 Vol. 96; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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