Adsorption and Reaction of [Re2(CO)10] on Ultrathin MgO Films Grown on a Mo(110) Surface: Characterization by Infrared Reflection-Absorption Spectroscopy and Temperature-Programmed Desorption

Abstract

The decarbonylation of [Rez(CO)lo] on ultrathin MgO( 11 1) films (-50 A) grown on a Mo ( 110) substrate was investigated with infrared reflection-absorption spectroscopy and temperature-programmed desorption/ decomposition. When [Re2(CO)lo] was adsorbed at 320 K, it reacted with the MgO(ll1) surface, forming a rhenium subcarbonyl, [Re(CO)4{OMg}12, where {OMg] represents oxygen on the MgO(ll1) surface. Upon heating to temperatures >400 K, [Re(C0)4{OMg}] 2 was decarbonylated, forming [Re(CO)3{OMgJ3]. Further heating to temperatures >600 K induced the formation of rhenium metal clusters. When it was adsorbed at 110 K, [Re2(CO)lo] condensed on MgO( 1 I l), with a fraction of the first layer decomposing to form [Re-(C0)4{0Mg}] 2. In temperature-programmed desorption experiments, [Re2(CO)lo] multilayers desorbed at 295K. An unidentified rhenium carbonyl species, probably rhenium pentacarbonyl, desorbed at 350 K. The C O stretching frequencies of the rhenium subcarbonyls were dependent on the coadsorption of water. The infrared spectra show that the symmetry of the surface-bound rhenium tricarbonyls is C3". The results are among the first characterizing the adsorption of metal complexes on well-defined metal oxide surfaces, and they demonstrate the value of structurally characterized supports for elucidation of the nature of the metal-support interface.

Structure of epitaxial thin TiOx films on W(110) as studied by low energy electron diffraction and scanning tunneling microscopy

“…[6][7][8] Also, the W͑110͒ surface can be considered a distorted hexagonal structure, and a wealth of literature is available on the growth of hexagonal metals on bcc͑110͒ surfaces. [6][7][8] Also, the W͑110͒ surface can be considered a distorted hexagonal structure, and a wealth of literature is available on the growth of hexagonal metals on bcc͑110͒ surfaces.…”

“…[1][2][3][4][5][6][7][8] Using a similar approach, catalytic phenomena have been well studied for monolayer films of metals grown on dissimilar metallic substrates. Performing detailed studies of the surface structure and chemistry of these materials remains difficult due to the common presence of impurities and structural defects.…”

Formation of a Manganese Tricarbonyl on the MgO Surface from Mn2(CO)10: Characterization by Infrared, Electron Paramagnetic Resonance, and X-ray Absorption Spectroscopies

“…Moreover, this behavior is also observed in the rhenium tricarbonyl complexes. 49,50 Conclusions A sample prepared by vapor deposition of Mn 2 (CO) 10 on MgO was treated in flowing O 2 at room temperature to form a species shown by IR and EXAFS spectroscopies to be a manganese tricarbonyl and shown by EPR spectroscopy to incorporate manganese in an oxidation state greater than +2. The EXAFS data and electron counting lead to the inference that the species is a d 4 complex bonded to three oxygen atoms of the MgO support as shown in Scheme 1.…”

Ultrathin, ordered oxide films on metal surfaces

“…The growth of epitaxial and stoichiometric MgO(111) thin films on a Mo(110) surface has been demonstrated using LEED, XPS, AES, and LEIS [106,107]. The MgO(111)/Mo(110) film is stable up to 1400 K, and is reduced by the Mo substrate at higher temperature, forming MoO 3 and Mg vapor.…”