Valence ionizations of olefins coordinated to metals. Olefin dicarbonyl(eta/sup 5/-(methyl and pentamethyl)cyclopentadienyl)manganese complexes

Journal Article · Wed Nov 18 04:00:00 EST 1981 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00413a011· OSTI ID:5807654

Calabro, D C; Lichtenberger, D L

The He I and He II valence photoelectron spectra of (eta/sup 5/-C/sub 5/H/sub 5-n/(CH/sub 3/)/sub n/)Mn(CO)/sub 2/L (n = 1 and 5; L = C/sub 2/H/sub 4/ and C/sub 3/H/sub 6/) are presented. The synthesis of the pentamethylcyclopentadienyl metal ethylene complex is reported for the first time. This complex is particularly helpful in revealing the ionization characteristics of the metal-olefin complexes. In each case the ionization that is associated primarily with the olefin ..pi.. bond (2e/sup -/ donor to the metal) is shifted to lower binding energy in the complex compared to the binding energy of the free ligand. Molecular orbital calculations are reported that agree very well with the shifts in ionization energies. The relative magnitudes of individual metal-olefin orbital interactions are evaluated. It is found that the ionizations and stability of the complexes are sensitive to the geometry changes that accompany coordination of the olefin. These distortions are associated with a lowered carbon-carbon bond strength and an increased metal-olefin bond strength through increased ..pi..-donor/..pi..*-acceptor interactions.

• Research Organization: Univ. of Arizona, Tucson
• OSTI ID: 5807654
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 103:23; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
BINDING ENERGY
DATA
ELECTRON SPECTROSCOPY
ENERGY
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
IONIZATION
MANGANESE COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS