Interactions of M(CO)6 (M=Cr, Mo, W) with surface sites of Al2O3: a theoretical study

Myllyoja, Sari; Suvanto, Mika; Kurhinen, Maria; Hirva, Pipsa; Pakkanen, Tapani A.

doi:10.1016/s0039-6028(99)00882-1

Cited by 10 publications

(10 citation statements)

References 62 publications

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“…IR data showing that a decline in intensity of the ν OH bands at 3772 and 3730 cm -1 (assigned to isolated OH groups of the support) as a result of adsorption of [Pt 2 Ru 4 (CO) 18 ] (Figure ), combined with the observation of CO 2 evolution (Figure , spectrum 1), imply that some of the surface hydroxyl groups interacted strongly with the carbonyl ligands. We infer that the interaction involved a nucleophilic attack; according to theoretical calculations, nucleophilic displacement of carbonyl ligands is the most energetically favored among the various interactions suggested for γ-Al 2 O 3 -supported metal carbonyls. Such a surface reaction could proceed via simple decarbonylation as a result of the cleavage of CO ligands of the metal carbonyl and formation of metal−O support bonds, or it could be similar to the reaction observed for [Ru 3 (CO) 12 ] with aqueous base (KOH), which results in the formation of [HRu 3 (CO) 11 ] - and evolution of CO 2 .…”

Section: Discussionmentioning

confidence: 86%

γ-Al₂O₃-Supported PtRu Clusters Prepared from [Pt₂Ru₄(CO)₁₈]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

et al. 2002

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Highly dispersed γ-Al2O3-supported PtRu clusters were prepared by decarbonylation of molecularly adsorbed [Pt2Ru4(CO)18] in He or H2 at temperatures in the range of 300−400 °C. Infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies were used to characterize the supported species before and after removal of the CO ligands. The IR and EXAFS spectra show that most of the [Pt2Ru4(CO)18] interacted weakly through its CO ligands with the surface hydroxyl groups of γ-Al2O3 and could be extracted into CH2Cl2, but a small fraction of the [Pt2Ru4(CO)18] interacted strongly with the support and could not be extracted. The strongly bonded species, characterized by a νco band at 2063 cm-1, formed as a result of nucleophilic attack of some support hydroxyl groups on carbonyl ligands, leading to the removal of these ligands as CO2 and formation of covalent bonds between the clusters and the oxygen atoms of the support. The EXAFS data show that after decarbonylation in He or H2 at 300−400 °C, the Pt−Ru cluster frame was changed relative to that of the supported [Pt2Ru4(CO)18]. The average Pt−Pt bond distance increased from 2.66 to 2.69 Å, and the Ru−Ru distance decreased from 2.83 to 2.64 Å. The corresponding Pt−Pt and Ru−Ru coordination numbers were found to be 2.0 and 4.0, respectively, indicating that slight agglomeration of the metal took place upon decarbonylation. The EXAFS data show that the Pt−Ru interactions were largely maintained after decarbonylation, so that highly dispersed Pt−Ru structures were present on the support. From the Pt−Pt and Ru−Ru coordination numbers it follows that decarbonylated clusters incorporate, on average, less than three and six Pt and Ru atoms, respectively, being the smallest such supported bimetallic clusters of platinum-group metals yet reported.

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Section: Discussionmentioning

confidence: 86%

γ-Al₂O₃-Supported PtRu Clusters Prepared from [Pt₂Ru₄(CO)₁₈]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

et al. 2002

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“…It is known, however, that the accuracy of the hybrid DFT functionals in predicting energetics for most systems, including transition metal systems, is better, comparing to the pure GGA functionals [85,86]. Becke three parameter hybrid functionals were successfully applied in calculations involving molybdenum compounds [55,57,88,89], including olefin metathesis catalysts [55,57]. Although the pure GGA functionals were used in such studies as well [53,56], other results reported in the present work are obtained with employing the B3LYP functional.…”

Section: Mo-alkylidene Schrock Complex (1880mentioning

confidence: 88%

Metathesis activity of monomeric Mo-methylidene centres on (100) and (110)C surfaces of γ-Al2O3––a comparative DFT study

Handzlik

2004

Surface Science

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“…The FOH -SiO 2 surface corresponds to a substrate prepared under wet chemical conditions in the absence of an electron or ion beam. In accordance with the available experimental results, CO ligands of W(CO) 6 have been used to bond to the substrate 46 . Three different orientations are considered which differ in the number of CO ligands bonding to the surface.…”

Section: Interaction Of W(co)6 With the Fully Hydroxylated Sio2 Subst...mentioning

confidence: 94%

“…3 (b) and (c), which show that the HOMO is made up of W 5d while the LUMO is dominated by p orbitals of the CO ligands. 6 have been used to bond to the substrate 46 . Three different orientations are considered which differ in the number of CO ligands bonding to the surface.…”

Section: A Electronic Structure Of the Sio2 Substratementioning

confidence: 99%

Interaction of W(CO)6with SiO2surfaces: A density functional study

et al. 2011

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The interaction of tungsten hexacarbonyl W(CO)6 precursor molecules with SiO2 substrates is investigated by means of density functional theory calculations with and without inclusion of long range van der Waals interactions. We consider two different surface models, a fully hydroxylated and a partially hydroxylated SiO2 surface, corresponding to substrates under different experimental conditions. For the fully hydroxylated surface we observe only a weak interaction between the precursor molecule and the substrate with physisorption of W(CO)6. Inclusion of van der Waals corrections results in a stabilization of the molecules on this surface, but does not lead to significant changes in the chemical bonding. In contrast, we find a spontaneous dissociation of the precursor molecule on the partially hydroxylated SiO2 surface where chemisorption of a W(CO)5 fragment is observed upon removal of one of the CO ligands from the precursor molecule. Irrespective of the hydroxylation, the precursor molecule prefers binding of more than one of its CO ligands. In the light of these results, implications for the initial growth stage of tungsten nano-deposits on SiO2 in an electron beam induced deposition process are discussed.

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Interactions of M(CO)6 (M=Cr, Mo, W) with surface sites of Al2O3: a theoretical study

Cited by 10 publications

References 62 publications

γ-Al₂O₃-Supported PtRu Clusters Prepared from [Pt₂Ru₄(CO)₁₈]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

γ-Al₂O₃-Supported PtRu Clusters Prepared from [Pt₂Ru₄(CO)₁₈]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

Metathesis activity of monomeric Mo-methylidene centres on (100) and (110)C surfaces of γ-Al2O3––a comparative DFT study

Interaction of W(CO)6with SiO2surfaces: A density functional study

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Interactions of M(CO)6 (M=Cr, Mo, W) with surface sites of Al2O3: a theoretical study

Cited by 10 publications

References 62 publications

γ-Al2O3-Supported PtRu Clusters Prepared from [Pt2Ru4(CO)18]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

γ-Al2O3-Supported PtRu Clusters Prepared from [Pt2Ru4(CO)18]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

Metathesis activity of monomeric Mo-methylidene centres on (100) and (110)C surfaces of γ-Al2O3––a comparative DFT study

Interaction of W(CO)6with SiO2surfaces: A density functional study

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γ-Al₂O₃-Supported PtRu Clusters Prepared from [Pt₂Ru₄(CO)₁₈]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies

γ-Al₂O₃-Supported PtRu Clusters Prepared from [Pt₂Ru₄(CO)₁₈]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies