title: Photoelectron Spectra of Trimethylphosphine-Substituted Tungsten Carbonyls: Ligand Field Effects, Ligand Additivity Effects, and Core-Valence Ionization Correlations.
abstract: High-resolution broad-scan gas-phase photoelectron spectra using synchrotron radiation (including valence, inner valence, and core levels) are reported for a series of trimethylphosphine-substituted tungsten carbonyls: W(CO)(6), W(CO)(5)PMe(3), cis-W(CO)(4)(PMe(3))(2), trans-W(CO)(4)(PMe(3))(2), and fac-W(CO)(3)(PMe(3))(3). The inner valence and core level spectra are interpreted by comparison with the published spectra of W(CO)(6) and other metal carbonyls. High-resolution valence level spectra of these complexes are also obtained by He I radiation. Fine structure, resulting from spin-orbit splitting, ligand field splittings, and vibrational coupling is resolved in the spectra of both W 5d and W 4f regions. Ligand field splittings on both the W 5d and W 4f levels increase in the order W(CO)(6) approximately fac-W(CO)(3)(PMe(3))(3) < W(CO)(5)PMe(3) </= cis-W(CO)(4)(PMe(3))(2) < trans-W(CO)(4)(PMe(3))(2). For the first time, the phosphorus 2p spin-orbit components of the phosphine complexes have been resolved. The binding energies (or ionization potentials) in the spectra of both W 5d valence level and W 4f core level regions are shifted almost linearly to lower energy with each successive step of ligand substitution. The shift per phosphine substitution is 0.66 +/- 0.03 eV for the W 5d ionizations and 0.76 +/- 0.03 eV for the W 4f ionizations (DeltaE(valence)/DeltaE(core) = 0.86 +/- 0.03). Similar linear shift trends are also found in the phosphorus 2p core level and phosphorus valence "lone-pair" ionizations. These data confirm the ligand additivity model predictions for these complexes.
authors.affiliation: Department of Chemistry, University of Western Ontario, London, Ontario, Canada N6A 5B7, and Canadian Synchrotron Radiation Facility, University of Wisconsin-Madison, Stoughton, Wisconsin 53589.
authors.forename: Jingcun
authors.initials: J
authors.lastname: Wu
authors.forename: G. Michael
authors.initials: GM
authors.lastname: Bancroft
authors.forename: Richard J.
authors.initials: RJ
authors.lastname: Puddephatt
authors.forename: Y. F.
authors.initials: YF
authors.lastname: Hu
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Li
authors.forename: K. H.
authors.initials: KH
authors.lastname: Tan