X-ray photoelectron spectra of dinitrogen chelating ligands with some transition metals

The complexes of two chelating agents, CDTA (trans-1,2-cyclohexanediaminetetraacetic acid) and EDTA (ethylenediaminetetraacetic acid), with Ni(II), Co(II) and Cu(II) are studied by means of X-ray photoelectron spectroscopy (XPS). The N1s spectrum of CDTA has two components at 398.5 (±0.2 eV) and 400.9 (±0.2 eV) while only one signal is found after coordination at 400.0±0.2 eV. EDTA shows a N1s spectrum with one component at 400.9±0.2eV. A negative shift of about -1.3eV is observed in its complexes. The results are compared with the literature data on the complexes in the solid state.     

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.     

X-ray photoelectron spectra of inorganic molecules XXlX. The characterization of mixed phosphido-phosphine and phosphido-phosphite complexes of transition metal carbonyl clusters using X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy has been found to provide a useful means of studying the electronic structure of the phosphorus atoms in PPh, PPh₂, PPh₃, PHPh and P(OMe)₃ ligands in a number of polynuclear cobalt and iron complexes.     

Polysilane derivatives of the transition metals III. Preparations and spectra of manganese and iron derivatives

The preparations of derivatives of Mn(CO)₅, Mn(CO)₄PPh₃ and π-Cp(CO)₂Fe containing the polysilyl ligands (Me₃Si)_nMe_3?nSi— (n = 1–3) are presented. The infrared and proton NMR spectra of the compounds are given and for the Mn(CO)₅ derivatives, force constants are derived and discussed in terms of the σ-donor/π-acceptor properties of the silyl ligands.     

He I photoelectron spectra of some camphor derivatives

He I photoelectron spectra of several camphor derivatives have been measured and assigned.     

Macro-N-heterocyclic compounds: X-ray photoelectron spectra and structure

Bi-, tri-, and tetradentate macroheterocylic ligands, i.e., structural analogs of phthalocyanine, are studied by X-ray photoelectron spectroscopy. The X-ray photoelectron spectra of N1s lines of the nitrogen atoms of these compounds are analyzed. The binding energies and integrated intensities of N1s lines of the nitrogen atoms are determined and the effective charges on the nitrogen atoms are calculated. The structures of bi-, tri-and tetradentate macroheterocyclic ligands containing isoindole, benzene, and pyridine fragments are established on the basis of the data obtained.     

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.     

Interpretation of X-ray photoelectron spectra of free nitroxyl radicals

N1s and O1s X-ray photoelectron spectra of stable nitroxyl radicals (substituted piperidine-1-oxyl, 2-imidazoline-1-oxyl, and 2-imidazoline-3-oxide-1-oxyl) and also diamagnetic derivatives with a {ONCNO} fragment are measured. It is shown that the structure of N1s and O1s X-ray photoelectron spectra of nitroxyls is determined by charge transfer processes between different parts of the molecule to screen the X-ray hole and the spin-spin interaction of unpaired electrons on the HOMO and 1s level.     

X-ray photoelectron spectra of Rh(III) trifluoroacetate

A study was made of the x-ray photoelectron spectra of Rh(I) and Rh(III) trifluoroacetate complexes. It was shown by using the Cls bond energies of the carboxylate carbon atom as a basis that bridging and monodentate coordination of the trifluoroacetate group could be distinguished with high resolution.Institute of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1549–1551, July, 1992.     

X-ray photoelectron spectra of ruthenium(II) phthalocyanines

Summary The Ru 3d_5/2 and 3p_3/2 x-ray photoelectron spectra of mono-and non-chlorinated ruthenium phthalocyanines were measured and the collected data on the core-level binding energies of ruthenium have been used to assess the oxidation state of the metal and the composition of the macrocyclic ligands.     

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 of ylide—TCNQ charge-transfer complexes

Charge-transfer complexes of TCNQ with ylides, new-type donors, were synthesized and the X-ray photoelectron spectra of these complexes were measured. A broad satellite caused by TCNQ radicals observed.     

Identification of conjugate electron transitions in X-ray photoelectron spectra

The regularities of the electron energy dissipation found in the subsurface atomic layer are valid in the bulk of a solid, too. On the example of model graphite-based materials it is shown that energy losses in X-ray photoelectron spectra agree with the calculated valence electron excitation spectra in analogous unit cells. The control of conjugate electron transitions opens the way to gain new data on the geometry, character, and order of bonding between atoms in the sample by the conventional electron spectroscopy and quantum chemistry methods.     

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.     

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.     

Substituent effects on the photoelectron spectra of benzene derivatives

Systematics in the ionization energies corresponding to the different π orbitals of para, meta and ortho-disubstituted benzenes obtained from PES have been investigated. The data have been discussed in terms of correlations with substituents constants and such correlations are shown to provide the basis to differentiate steric from electronic effects in the case of ortho derivatives. Ionization energies from PES corresponding to the lone pair orbitals of substituents in related series of p-disubstituted benzenes are shown to vary systematically with the substituent constants.     

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.