X-ray photoelectron spectra and structure of cobalt compounds with N-heterocyclic ligands

The electronic structure of cobalt complexes with bi-, tri-, and tetradentate ligands and the mutual influence of ligands in them have been studied by X-ray photoelectron spectroscopy. The Co2p, N1s, and O1s photoelectron spectra have been studied. Unlike low-spin Co(III) complexes, the high-spin Co(II) compound exhibits a strong satellite line in the Co2p spectrum. For the high-spin Co(II) compound having unpaired 3d electrons, the Co2p _1/2-Co2p _3/2 spin-orbit splitting is larger than that in the low-spin Co(III) complexes. All cobalt complexes under consideration contain strongly bound dioxygen, which can be considered an inherent structural unit.     

Satellite Phenomena in X-ray photoelectron spectra of actinide compounds

Satellite structure to one side of the 4f photoelectron lines of a number of thorium compounds has been investigated. The origin of these and similar lines observed in uranium compounds is discussed together with those recorded near the 3d photoelectron signals of lanthanide compounds.     

X-ray photoelectron spectra and structure of polynuclear nickel complexes

Mono- and binuclear nickel complexes of different stoichiometry have been studied by X-ray photoelectron spectroscopy (XPS). The Ni2p, Ni3p, and N1s X-ray photoelectron spectra have been examined, and the role of a ligand in their formation has been determined. As distinct from a low-spin Ni(II) complex, the Ni2p spectra of high-spin Ni(II) compounds show strong satellite lines. For high-spin Ni(II) complexes, which have unpaired 3d electrons, the Ni2p _1/2-Ni2p _3/2 spin-orbit splitting is larger than that for a low-spin Ni(II) compound. The presence or absence of the satellite structure has made it possible to classify these complexes with regard to their magnetic properties. The difference between the Ni2p _3/2 and N1s binding energies has made it possible to estimate the covalence of the metal-ligand bond. The XPS results are consistent with X-ray crystallography data.     

X-ray photoelectron spectra and electronic structure of rare-earth orthovanadates

Photoelectron spectra of 4d and valence states in RVO₄ (R = Y, Nd, Eu, Gd, Tb, Dy, Yb) have been investigated. The experimental spectra are interpreted using the results of the Xα discrete variational method calculations for orthovanadates. Transformations of electronic structure and covalency in the RVO₄ series are discussed. It is shown that lanthanide 4f orbitals significantly mix with the O 2pAO's and hybridize with the rare-earths 5pAO's. The 5p levels spin-orbital splitting in orthovanadates has been evaluated.     

Boron chelate complexes: X-ray and UV photoelectron spectra and electronic structure

Published data on the electronic structure of boron chelates are summarized for the first time. Ultraviolet photoelectron spectra of vapors, X-ray photoelectron spectra of molecular crystals, and results of modeling within the framework of the density functional theory are analyzed. Data on the effect of substituents on the electronic structure of complexes are systematized.     

Satellite phenomena in the X-ray photoelectron spectra of some titanium compounds

The extra peak, located at ca 13.6 eV on the high-binding-energy side of the core levels of titanium in rutile, anatase and barium titanate, probably arises from a shake-up process involving an O(2p) → Ti(4s) transition.     

X-ray photoelectron spectra and structure of 2-(2-phenylhydrazono) acetoacetanilide

2-(2-Phenylhydrazono)acetoacetanilide, itsN-methyl derivatives, and model compounds were studied by X-ray photoelectron spectroscopy. The chemical shifts were obtained from the¹³C NMR spectra. A correlation between the calculated charges, the binding energies on N atoms, and the¹³C NMR chemical shifts was found. The analysis of the XPS data and the¹³C NMR chemical shifts led to the conclusion that crystalline 2-(2-phenylhydrazono)acetoacetanilide exists mainly in the oxo hydrazone form. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 488–491, March, 1999.     

X-ray photoelectron spectroscopy of boron compounds

The results of X-ray photoelectron (XPS) studies of boron compounds (predominantly boron hydrides and their derivatives — 49 compounds) are presented. The results are analyzed to form a representative set of XPS data for the boron element.     

Paramagnetism and shake-up satellites in X-ray photoelectron spectra

The correlation between paramagnetism and the shake-up satellites in the X-ray photoelectron spectra of the 3d transitional-metal compounds is examined and explained in terms of modified selection rules governing the shake-up transitions.     

X-ray photoelectron spectra of polynuclear manganese complexes

Manganese trimethylacetate complexes with different ligand environments were studied by X-ray photoelectron spectroscopy (XPS). Changes in the Mn 2p, C 1s, O 1s, and N 1s X-ray photoelectron spectra caused by the substitution of Mn → N coordination bonds for Mn → O coordination bonds were examined. In the spectra of manganese trimethylacetate complexes, the satellite component was identified, which is evidence of the high-spin state of manganese atoms. An increase in the magnetic moment of the manganese complexes, both with the oxygen and mixed oxygen-nitrogen environment, is accompanied by an increase in the spin-orbit splitting, the difference in E _b between the satellite and the Mn 2p _3/2 line, and the ratio between the integrated intensities of the satellite and the Mn 2p _3/2 line (I sat_3/2/I Mn 2p _3/2). The XPS data made it possible to determine the measure of covalence of the metal-ligand bond. The XPS results are consistent with X-ray crystallography data.     

Electronic structure of sulphur compounds—VII photoelectron spectra of thiocarbonyl heterocycles

The photoelectron spectra of α-substituted thiocarbonyl heterocycles have been analysed. By observing the effects of methyl substitution on the spectra, it was possible to assign the first five bands. These assignments were confirmed by semi-empirical calculations (CNDO/S).     

Dynamic effect on the structure of X-ray photoelectron spectra of lanthanide fluorides and oxides

Dynamic effect on the fine structure of X-ray photoelectron spectra of lanthanide oxides and fluorides is discussed. The Ln4p electron spectra are considerably complicated by the interaction between the configurations of themain one-hole and additional two-hole final states of 4p⁵4d⁵⁴fⁿ ↔ 4p⁶4d⁸fⁿ⁺¹ type. The effect of the nature of atoms in the nearest environment of lanthanide ions on the fine structure parameters is evaluated. Translated fromZhurnal Struktumoi Khimii, Vol. 39, No. 6, pp. 1059–1066, November–December, 1998.     

Structure of X-ray photoelectron, emission, and conversion spectra and molecular orbitals of uranium compounds

The fine structure of X-ray photoelectron spectra of uranium compounds in the range of electron binding energies from 0 to ∼50 eV is largely determined by the electrons of the outer and inner valence molecular orbitals arising from the valence atomic shells, including the U6p and Lns low-energy occupied atomic shells. This result is in agreement with the data of the electronic structure calculations of these compounds and confirmed by the nuclear electron (conversion) and X-ray emission spectroscopic investigations. It is shown that the fine structure of X-ray photoelectron spectra associated with the electrons of inner valence molecular orbitals makes it possible to judge the participation of the electrons of the occupied atomic shells in chemical bonding, the structure of the nearest environments of the atom, and the bond lengths in the compounds. The overall contribution of the electrons of these molecular orbitals to the absolute value of binding energy may prove to be comparable to the contribution of the electrons of the outer valence molecular orbitals to atomic bonding. This is a new and important fact in chemistry. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 6, pp. 1037–1046, November–December, 1998.     

Many-electron singularity in aggregate X-ray line and photoelectron spectra

It is generally admitted that the many-electron effects govern the shape of the discrete X-ray line and photoemission spectra. This phenomenon has been studied in bulk metals (Mahan, Nozières and de Dominicis model) where it is characterized by two effects: the Anderson orthogonality between the initial and final ground states and the \(|E|^{\alpha _H - 1} \) spectrum behaviour, whereE is the emitted particle energy defect (with respect to the one-electron energy) and α _H (with 0<α _H <1) and exponent related to the phase shifts δ at the Fermi level due to the localised hole potential. We study these two effects in limited media (closed loop shape withN=10 to 30 atoms). We observe that, asN increases, the ground state overlap tends toward zero in a way which is surprisingly close to the Anderson \(N^{ - \alpha _H /2} \) behaviour. TheE spectra are also obtained. They are very different from the bulk which will lead to asymmetry parameters smaller for aggregates than for the bulk. A discussion of the experimental results is presented.     

X-ray photoelectron spectra of polyhydrido complexes of tungsten and molybdenum

X-Ray photoelectron spectroscopy has been applied to study MH₄L₄(M = or Mo, L = PHPh₂, PMePh₂, PEtPh₂, PBuPh₂, PEt₂Ph, P(OPr-i)₃ or $\text{1}\text{2}$ dppe). It has been shown that tungsten in these compounds has a negative charge whereas the charge of molybdenum is almost zero.