Gas-phase ionization energetics, electron-transfer kinetics, and ion solvation thermochemistry of decamethylmetallocenes, chromocene, and cobaltocene

Journal Article · Fri Apr 01 00:00:00 EST 1994 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00016a023· OSTI ID:7267259

Ryan, M F; Richardson, D E ^[1]; Lichtenberger, D L; Gruhn, N E ^[2]

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1. Univ. of Florida, Gainesville, FL (United States)
2. Univ. of Arizona, Tucson, AZ (United States)

The gas-phase free energies of ionization, [Delta]G[sub i][degrees] for Cp*[sub 2]Mn, Cp*[sub 2]Fe, Cp*[sub 2]Ni, Cp*[sub 2]Os, Cp[sub 2]Cr, and Cp[sub 2]Co (Cp = [eta][sup 5]-cyclopentadienyl, Cp[sup *] = [eta][sup 5]-pentamethylcyclopentadienyl) have been determined by using the electron-transfer equilibrium (ETE) technique and Fourier transform ion cyclotron resonance mass spectrometry. The high-resolution valence photoelectron spectra of bis(benzene)chromium(0), Bz[sub 2]Cr, Cp*[sub 2]Os, and Cp*[sub 2]Ru have also been measured. Most of the [Delta]G[sub i][degrees] values are referenced to the estimated [Delta]G[sub i][degrees] value of Bz[sub 2]Cr, for which the narrow first ionization band at 5.473 [+-] 0.005 eV is assigned as the adiabatic ionization potential. The [Delta]S[sub i][degrees] for ionization of Bz[sub 2]Cr is assumed to be equal to the electronic entropy change, [Delta]S[sub elec][degrees] (=1.4 cal mol[sup [minus]1] K[sup [minus]1]), and the difference between the integrated heat capacities for Bz[sub 2]Cr and Bz[sub 2]Cr[sup +] is also assumed to be negligible near room temperature [Delta]H[sub i,0][degrees] [approx] [Delta]H[sub i,350][degrees], leading to [Delta]G[sub i][degrees] (Bz[sub 2]-Cr) = 125.6 [+-] 1.0 kcal mol[sup [minus]1]. Through the use of thermochemical cycles, estimates are given for the average heterolytic and homolytic M-Cp bond disruption enthalpies of Cp[sub 2]Cr[sup +/0] and Cp[sub 2]Co[sup +/0]. 46 refs., 7 figs., 4 tabs.

• DOE Contract Number: FG02-86ER13501
• OSTI ID: 7267259
• Journal Information: Organometallics; (United States), Vol. 13:4; ISSN 0276-7333
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
IONIZATION
FREE ENERGY
IONS
SOLVATION
ORGANOMETALLIC COMPOUNDS
REDOX REACTIONS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHROMIUM COMPLEXES
COBALT COMPLEXES
COMPILED DATA
CYCLOPENTADIENE
ELECTRON TRANSFER
ENTHALPY
ENTROPY
FOURIER TRANSFORM SPECTROMETERS
IRON COMPLEXES
MANGANESE COMPLEXES
NICKEL COMPLEXES
OSMIUM COMPLEXES
PHOTOELECTRON SPECTROSCOPY
RESONANCE IONIZATION MASS SPECTROSCOPY
SPECIFIC HEAT
THERMOCHEMICAL PROCESSES
THERMODYNAMICS
VOLTAMETRY
ALKENES
CHARGED PARTICLES
CHEMICAL REACTIONS
COMPLEXES
CYCLOALKENES
DATA
DIENES
ELECTRON SPECTROSCOPY
ENERGY
HYDROCARBONS
INFORMATION
KINETICS
MASS SPECTROSCOPY
MEASURING INSTRUMENTS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
POLYENES
REACTION KINETICS
SPECTROMETERS
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
661300 - Other Aspects of Physical Science- (1992-)
400102 - Chemical & Spectral Procedures