Photoelectron spectra of some compounds containing transition-metal–carbon σ-bond

Abstract

Photoelectron spectra of [MMe(-q-C5H5)(CO),] (M = Mo and W). [MMe(-q-C,H,)(CO),] (M = Fe and Ru). and [Fe(CH,CN) (r/-C5H5) (CO),] have been measured. The ionization energies for the metal-carbon a-bonding electrons are identified and compared with those of other transition-metal alkyl compounds.cyclopentadienylmetal a l k y l ~, ~ and carbonylmetal al k y l ~. ~ A recent report of the spectrum of [FeMe(-q-C,H,)(CO),] OX1 3QRIONIZATIONS associated with transition-metal-carbon a bonds have been characterized for pure metal alkyls,l.2 prompts us to report our study of this and related

Sequential bond energies of iron carbonyl Fe(CO)x+ (x = 1-5): systematic effects on collision-induced dissociation measurements

“…Even using their CID value for £>°(Fe+-CO) is not enough to account for the discrepancy between the sum of the BDEs they report and the literature thermochemistry discussed above, however. Similar difficulties may also affect Distefano's PI experiment,17 although his value for //°(1), 6.05 ± 0.1 eV (139.5 ± 2.3 kcal/mol), is in agreement with the literature value. From this examination of the literature thermochemistry, we conclude that the possibility of the literature thermochemistry being widely in error is small.…”

“…The value of ,//°(1) given in the text, 149.9 ± 1. 6 kcal/mol, is that reported by NAFN, who derived it from the difference in the Fe+ and Fe(CO)s+ appearance energies as measured by PI.…”

“…The other columns are BDEs derived from differences between the thresholds for formation of Fe(CO),+ and Fe(CO),_,+. 6 The cross sections for dissociation products of FeCO+ and Fe(CO)2+ are independent of the pressure of Xe in the gas cell.…”

Synthesis and Luminescence Spectroscopy of a Series of [η5-CpFe(CO)2] Complexes Containing 1,12-Dicarba-closo-dodecaboranyl and -ylene Ligands

“…Spectroscopic studies of Fp-X complexes suggest that the lowest energy transition is primarily ligand field in character. [13][14][15][16][17][18][19][20][21][22][23][24] Photoelectron ionization spectra were used to assign the highest occupied molecular orbital to an iron 3d antibonding molecular orbital. 15,16 In addition, the extinction coefficient of the lowest energy band in the Fp-Cl absorption spectrum is consistent with ligand field electronic transitions typically exhibiting extinction coefficients on the order of 10 1 -10 2 M -1 cm -1 .…”

Metal-Centered 17-Electron Radicals CpM(CO)3• (M = Cr, Mo, W): A Combined Negative Ion Photoelectron Spectroscopic and Theoretical Study

“…Our knowledge about their electronic structures and chemical bonding has instead largely come from theoretical investigations using the Hartree–Fock method and extended Hückel molecular orbital and fragment analysis. − Information about radical cations isolobal with neutral group 6 radicals CpM(CO) 3 • , e.g. [(benzene)M(CO) 3 ] • + (M = Cr, Mo, W) and [CpMn(CO) 3 ] • + , has been obtained by photoionization of the respective neutral 18e complexes, − and MO schemes for these compounds have been derived. − …”