The electronic nature of the metal-metal quadruple bond: Variable photon energy photoelectron spectroscopy of Mo[sub 2](O[sub 2]CCH[sub 3])[sub 4]

Journal Article · Wed Dec 16 04:00:00 EST 1992 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00052a053· OSTI ID:6538592

Lichtenberger, D L; Ray, C D ^[1]; Stepniak, F; Chen, Yu; Weaver, J H ^[2]

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1. Univ. of Arizona, Tucson (United States)
2. Univ. of Minnesota, Minneapolis (United States)

Variable-energy photoelectron spectroscopy of thin film Mo[sub 2](O[sub 2]CCH[sub 3])[sub 4] on a GaAs substrate in ultrahigh vacuum is used to examine the valence ionizations of the quadruple metal-metal bond. The changes in photoionization cross sections with photon energy over a range of 40 to 90 eV are examined. The metal-based, [sigma], [pi], and [delta] ionizations of the quadruple bond are strongly enhanced relative to the acetate-based ionizations in the region of photon energies from 40 to 50 eV. This is consistent with a molybdenum 4p to 4d resonance and super-Coster-Kronig Auger enhancement of the metal-based ionizations. The extent of resonance enhancement is related to the amount of Mo 4d character associated with the ionization. The [pi] ionization of the Mo-Mo quadruple bond has the largest contribution from the Mo 4d orbitals. The [delta] and [sigma] ionizations of the metal-metal bond contain smaller amounts of Mo 4d character, and some Mo 4d character is observed in the acetate-based ionizations. This is explained in terms of significant overlap and mixing of the [delta] and [sigma] components with the ligand orbitals. Also, in the case of the [sigma] component, there is a possible filled/filled interaction between the Mo 4d[sub z[sup 2]] orbital on one metal and the Mo 4p[sub z] orbital on the adjoining metal. These interactions have significant impact on the properties of these complexes. 26 refs., 10 figs.

• OSTI ID: 6538592
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 114:26; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
ACETATES
CARBOXYLIC ACID SALTS
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
FILMS
IONIZATION
MOLYBDENUM COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
REFRACTORY METAL COMPOUNDS
RESONANCE
SPECTROSCOPY
THIN FILMS
TRANSITION ELEMENT COMPOUNDS