Magnesia-supported tetrairidium clusters derived from [Ir[sub 4](CO)[sub 12]]

Journal Article · Thu Aug 25 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100085a026· OSTI ID:6970851

Triantafillou, N D; Gates, B C ^[1]

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1. Univ. of Delaware, Newark, DE (United States)

The chemistry of iridium clusters formed from [Ir[sub 4](CO)[sub 12]] on basic MgO surfaces was investigated with infrared and extended X-ray absorption fine structure (EXAFS) spectroscopies. The chemistry of iridium carbonyls on MgO is comparable to that of iridium carbonyls in basic solutions. The adsorption of [Ir[sub 4](CO)[sub 12]] on MgO with high, intermediate, and low surface hydroxyl group concentrations led to the formation of structures that are suggested on the basis of infrared spectra to be [Ir[sub 4](CO)[sub 11]COH(O)]. [HIr[sub 4](CO)[sub 1 1]][sup [minus]], and [Ir[sub 8](CO)[sub 22]][sup 2[minus]], respectively, where (O) represents oxygen of the MgO surface. Decar bonylation of the iridium carbonyl clusters on MgO led to the formation of iridium clusters. The reaction of [[sub 4](CO)[sub 12]] with highly dehydroxylated MgO followed by treatment in flowing He at 325[degree]C for 2 h and flowing H[sub 2] at 300[degree]C for 2 h at 1 atm led to formation of clusters that are modeled on the basis of EXAFS spectra as predominantly Ir[sub 4] tetrahedra. The reactions of [Ir[sub 4](CO)[sub 12]] with highly hydroxylated MgO followed by treatment in flowing He at 325[degree]C for 2 h and flowing H[sub 2] at 300[degree]C for 2 h at 1 atm led to the formation of larger iridium clusters, with average diameters of about 12 A. 56 refs., 8 figs., 4 tabs.

• DOE Contract Number: FG02-87ER13790; FG05-89ER45384; AC02-76CH00016
• OSTI ID: 6970851
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:34; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
COMPILED DATA
COMPLEXES
DATA
DEUTERIUM
ELECTRON MICROSCOPY
ELEMENTS
FLUIDS
GASES
HEAVY WATER
HELIUM
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
INFRARED SPECTRA
IRIDIUM
IRIDIUM COMPLEXES
ISOTOPES
LIGHT NUCLEI
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
METALS
MICROSCOPY
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RARE GASES
SOLID CLUSTERS
SORPTION
SPECTRA
SPECTROSCOPY
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY
WATER
X-RAY SPECTROSCOPY