Complete ligand loss in electron ionization of the weakly bound organometallic tungsten hexacarbonyl dimer

Neustetter, Michael; Mauracher, Andreas; Limão-Vieira, P.; Denifl, Stephan

doi:10.1039/c6cp00558f

Cited by 7 publications

(11 citation statements)

References 24 publications

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“…The dimer metal cation W 2 + resulting from electron ionization of the neutral W(CO) 6 dimer was reported by Neustetter et al [ 23 ] showing the fast conversion of the weak cluster bond into a strong covalent metallic bond. In comparison to electron collisions, anisotropic coulombic explosion of CO ligands upon multiple ionization in a femtosecond laser field was recently reported by Tanaka et al [ 24 ] for Cr(CO) 6 , Mo(CO) 6 and W(CO) 6 .…”

Section: Introductionmentioning

confidence: 89%

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

Khreis

Ameixa

Silva

et al. 2017

Beilstein J. Nanotechnol.

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Interactions of low-energy electrons with the FEBID precursor Cr(CO)6 have been investigated in a crossed electron–molecular beam setup coupled with a double focusing mass spectrometer with reverse geometry. Dissociative electron attachment leads to the formation of a series of anions by the loss of CO ligand units. The bare chromium anion is formed by electron capture at an electron energy of about 9 eV. Metastable decays of Cr(CO)5 − into Cr(CO)4 −, Cr(CO)4 − into Cr(CO)3 − and Cr(CO)3 − into Cr(CO)2 − are discussed. Electron-induced dissociation at 70 eV impact energy was found to be in agreement with previous studies. A series of Cr(CO)nC+ (0 ≤ n ≤ 3) cations formed by C–O cleavage is described for the first time. The metastable decay of Cr(CO)6 + into Cr(CO)5 + and collision-induced dissociation leading to bare Cr+, are discussed. In addition, doubly charged cations were identified and the ration between doubly and singly charged fragments was determined and compared with previous studies, showing considerable differences.

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Section: Introductionmentioning

confidence: 89%

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

Khreis

Ameixa

Silva

et al. 2017

Beilstein J. Nanotechnol.

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“…Negative ion states of transition-metal hexacarbonyls have been obtained by electron transmission spectroscopy (ETS) with W(CO) 6 attachment energies of 1.53, 2.46 and 4.26 eV [ 27 ]. We note electron impact ionisation studies on the appearance energies of bare tungsten hexacarbonyl [ 28 ], on the fragmentation pathways of W(CO) 6 clusters [ 29 ] and on the complete ligand loss of weakly bound W(CO) 6 dimer [ 30 ]. As far as neutral dissociation (ND) is concerned, Zlatar et al [ 25 ] have reported on the relevance of electronically excited precursors yielding neutral fragmentation, although the products of ND processes appear to be more difficult to monitor than charged products in mass spectrometry.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive investigation of the electronic excitation of W(CO)₆by photoabsorption and theoretical analysis in the energy region from 3.9 to 10.8 eV

Mendes¹,

Regeta²,

Silva³

et al. 2017

Beilstein J. Nanotechnol.

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High-resolution vacuum ultraviolet photoabsorption measurements in the wavelength range of 115–320 nm (10.8–3.9 eV) have been performed together with comprehensive relativistic time-dependent density functional calculations (TDDFT) on the low-lying excited sates of tungsten hexacarbonyl, W(CO)6. The higher resolution obtained reveals previously unresolved spectral features of W(CO)6. The spectrum shows two higher-energy bands (in the energy ranges of 7.22–8.12 eV and 8.15–9.05 eV), one of them with clear vibrational structure, and a few lower-energy shoulders in addition to a couple of lower-energy metal-to-ligand charge-transfer (MLCT) bands reported in the literature before. Absolute photoabsorption cross sections are reported and, where possible, compared to previously published results. On the basis of this combined experimental/theoretical study the absorption spectrum of the complex has been totally re-assigned between 3.9 and 10.8 eV under the light of spin–orbit coupling (SOC) effects. The present comprehensive knowledge of the nature of the electronically excited states may be of relevance to estimate neutral dissociation cross sections of W(CO)6, a precursor molecule in focused electron beam induced deposition (FEBID) processes, from electron scattering measurements.

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“…However, we have recently reported on the complete ligand loss in electron ionization of the weakly bound organometallic tungsten hexacarbonyl dimer, leading to bare W 2 + metal cation formation. 19 Figure 1 shows the electron ionization mass spectrum above 180 u (the weight of W + is ∼184 u) up to the monomer for two different expansion conditions. The upper panel (a) shows the mass spectrum, when the neutral beam consisted of monomers only (obtained by using a low amount of helium as seeding gas), while the lower panel was recorded with conditions mentioned in Section II which led to clustering.…”

Section: A Ionization Of Bare Tungsten Hexacarbonyl and Its Clustersmentioning

confidence: 99%

“…Recently, we reported the complete ligand loss in electron ionization of the weakly bound organometallic tungsten hexacarbonyl dimer. 19 Such extensive fragmentation process is only possible by fast conversion of the weak van-der-Waals bond into a strong covalent bond between the metal moieties yielding W 2 + . 19 In the present study, we report the electron ionization mass spectrum up to the W(CO) 6 dimer at the electron energy of 70 eV.…”

Section: Introductionmentioning

confidence: 99%

“…19 Such extensive fragmentation process is only possible by fast conversion of the weak van-der-Waals bond into a strong covalent bond between the metal moieties yielding W 2 + . 19 In the present study, we report the electron ionization mass spectrum up to the W(CO) 6 dimer at the electron energy of 70 eV. In addition, the threshold behavior of various ionic species resulting from the electron ionization is reported.…”

Section: Introductionmentioning

confidence: 99%

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Fragmentation pathways of tungsten hexacarbonyl clusters upon electron ionization

Neustetter

Maalouf

Limão-Vieira

et al. 2016

The Journal of Chemical Physics

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Electron ionization of neat tungsten hexacarbonyl (W(CO)6) clusters has been investigated in a crossed electron-molecular beam experiment coupled with a mass spectrometer system. The molecule is used for nanofabrication processes through electron beam induced deposition and ion beam induced deposition techniques. Positive ion mass spectra of W(CO)6 clusters formed by electron ionization at 70 eV contain the ion series of the type W(CO)n (+) (0 ≤ n ≤ 6) and W2(CO)n (+) (0 ≤ n ≤ 12). In addition, a series of peaks are observed and have been assigned to WC(CO)n (+) (0 ≤ n ≤ 3) and W2C(CO)n (+) (0 ≤ n ≤ 10). A distinct change of relative fragment ion intensity can be observed for clusters compared to the single molecule. The characteristic fragmentation pattern obtained in the mass spectra can be explained by a sequential decay of the ionized organometallic, which is also supported by the study of the clusters when embedded in helium nanodroplets. In addition, appearance energies for the dissociative ionization channels for singly charged ions have been estimated from experimental ion efficiency curves.

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Complete ligand loss in electron ionization of the weakly bound organometallic tungsten hexacarbonyl dimer

Abstract: We observed the bare W2(+) metal cation upon electron ionization of the weakly bound W(CO)6 dimer. This metal cation can be only observed due to the fast conversion of the weak cluster bond into a strong covalent bond between the metal moieties.

Cited by 7 publications

References 24 publications

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

Comprehensive investigation of the electronic excitation of W(CO)₆by photoabsorption and theoretical analysis in the energy region from 3.9 to 10.8 eV

Fragmentation pathways of tungsten hexacarbonyl clusters upon electron ionization

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Complete ligand loss in electron ionization of the weakly bound organometallic tungsten hexacarbonyl dimer

Abstract: We observed the bare W2(+) metal cation upon electron ionization of the weakly bound W(CO)6 dimer. This metal cation can be only observed due to the fast conversion of the weak cluster bond into a strong covalent bond between the metal moieties.

Cited by 7 publications

References 24 publications

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)6)

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)6)

Comprehensive investigation of the electronic excitation of W(CO)6by photoabsorption and theoretical analysis in the energy region from 3.9 to 10.8 eV

Fragmentation pathways of tungsten hexacarbonyl clusters upon electron ionization

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Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

Interactions of low-energy electrons with the FEBID precursor chromium hexacarbonyl (Cr(CO)₆)

Comprehensive investigation of the electronic excitation of W(CO)₆by photoabsorption and theoretical analysis in the energy region from 3.9 to 10.8 eV