A comprehensive study of the electronic structure of trinuclear molybdenum complexes (NH4)2[Mo3S13] and [Mo3S7(dtc)3]Br with cluster core {Mo3S7} and [Mo3S4(tu)8H2O]Cl4 complexes with cluster core {Mo3S4} is conducted by X-ray emission spectroscopy (XES), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) spectroscopy, and quantum chemistry methods. Data were obtained on the partial atomic composition of the highest occupied molecular orbitals and unoccupied molecular orbitals and the nature of atomic interactions within cluster cores.

Методами рентгеновской эмиссионной спектроскопии (РЭС), рентгеновской фотоэлектронной спектроскопии (РФЭС), рентгеновской спектроскопии поглощения (XANES) и квантовой химии проведено детальное исследование особенностей электронной структуры трехъядерных комплексов молибдена (NH4)2[Mo3S13] и [Mo3S7(dtc)3]Br с кластерным ядром {Mo3S7}, а также [Mo3S4(tu)8H2O]Cl4 с кластерным ядром {Mo3S4}. Получены данные о парциальном атомном составе высших занятых и свободных молекулярных орбиталей и характере взаимодействий между атомами внутри кластерного ядра.

Исследовано электронное строение фталоцианинов цинка ZnPc и ZnPcF16 рентгеноспектральным и рентгеноэлектронным методами. Проанализированы экспериментальные и теоретические параметры энергетического спектра и парциального состава ВЗМО молекул этих соединений. Показано, что граничная высокоэнергетическая область высших занятых молекулярных орбиталей (ВЗМО) ZnPc состоит из вкладов атомных орбиталей (АО) 2рπ атомов азота неэквивалентных групп (Nα, Nβ) и из 2рπ периферийных атомов углерода (Сβγδ) с участием 3d-орбиталей цинка как π-типа (3dyz, 3dz2), так и σ-типа (3dxy). Установлено, что атомы фтора и центральный атом цинка в ZnPcF16 взаимодействуют друг с другом посредством образования делокализованных π-орбиталей с участием pπ-орбиталей атомов углерода, принадлежащих группам α, β, γ, δ, а также pπ-орбиталей атомов азота групп α и β. ВЗМО ZnPcF16 построена главным образом из 2рx-, 2рy-АО азота (Nα и Nβ) и углерода (Сβ и Сγδ) с незначительным участием 3dxz, yz-орбитали цинка.

The electronic structure of zinc phthalocyanines ZnPc and ZnPcF16 is studied by X-ray emission and X-ray photoelectron spectroscopy methods. Experimental and theoretical parameters of the energy spectrum are analyzed along with the partial composition of highest occupied molecular orbitals (HOMOs) of the molecules of these compounds. It is shown that the frontier high-energy region of ZnPc HOMOs consists of 2pπ atomic orbitals (AOs) of nitrogens from non-equivalent groups (Nα, Nβ) and 2pπ orbitals of peripheral carbons (Cβγδ) with the participation of 3d orbitals of zinc which belong to both π (3dyz, 3dz2) and σ (3dxy) types. It is established that fluorine atoms and the central zinc atom in ZnPcF16 interact with each other by forming delocalized π orbitals with the participation of carbon pπ orbitals belonging to α, β, γ, δ groups as well as nitrogen pπ orbitals of α and β groups. The HOMO of ZnPcF16 consists mainly of 2px and 2py AOs of nitrogen (Nα and Nβ) and carbon (Cβ and Cγδ) with a small contribution of the 3dxz, yz orbital of zinc.

The electronic structure of mono- and binuclear platinum complexes with N-phenyl-o benzosemiquinondiimine ligands was studied using X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and the density functional theory. The oxidation state of the central platinum ion corresponds to that of Pt(II). Upon the transition from the trans-complex 1 to the cis-complex 2 and to the binuclear complex 3, the electron density on platinum and nitrogen atoms decreases thus testifying the participation of platinum and nitrogen atoms in the oxidation processes and in the formation of binuclear complex 3.

Методами рентгеновской фотоэлектронной спектроскопии, рентгеновской спектроскопии поглощения и теории функционала плотности изучено электронное строение моно- и биядерных комплексов платины с N-фенил-о-бензосемихинондииминовыми лигандами. Показано, что степень окисления центрального иона платины соответствует Pt(II). При переходе от транс-комплекса 1 к цис-комплексу 2 и биядерному комплексу 3 происходит уменьшение электронной плотности на ионах платины и атомах азота, что свидетельствует об участии в процессах окисления и образования биядерного комплекса 3 (атомов азота и ионов платины).

Solid solutions Mo1–xNbxS2 (x = 0, 0.05, 0.10, and 0.15) crystallizing in the hexagonal structure 2H-MoS2 are synthesized. The samples are characterized by powder X-ray diffraction (XRD) and Raman spectroscopies, X-ray photoelectron spectroscopy (XPS), and quantum chemical calculations (DFT). The changes occurring in the electronic properties of high-resistivity semiconductor MoS2 and indicating metallic behavior of obtained solid solutions Mo1–xNbxS2 are not accompanied by substantial changes in the atomic photoelectron spectra.

For the following compounds [Nb2S4(acac)(4)] (acac = acetylacetonate), K-4[Nb2S4(ox)(4)] (ox = oxalate) and Nb2S4Br4 containing dinuclear cluster core {(Nb4+)(2)(mu-S-2(2-))(2)}(4+) (simply (Nb2S4)(4+)) the electronic structure has been experimentally and theoretically investigated through X-ray emission (XES), X-ray photoelectron (XPS) spectroscopies and Density functional theory (DFT). The bonding and antibonding highest occupied molecular orbitals (HOMOs) observed in the X-ray emission spectra have been characterized by the analysis of overlap populations and the partial atomic composition considering the nature of the electron density distribution. Furthermore, the effective atomic charges have been determined. (C) 2018 Elsevier Ltd. All rights reserved.

The synthesis, characterization, experimental X-ray photoelectron spectra (XPS) and density-functional theory (DFT) investigations on solid solutions of Mo1-xRexS2 (x = 0.05, 0.10, 0.15 and 0.20) are reported herein. It is shown that even at a low concentration of dopant Re atoms, clustering occurs. At an Re concentration of 5% the formation of dimer-like impregnations is observed. An increase in the dopant concentration leads to an increase in the amount of clustered rhenium atoms and to the formation of rhombic clusters. The absence of magnetism within the studied Mo1-xRexS2 solid solutions allowed us to suggest a mechanism for the distribution of rhenium inside molybdenum disulphide through the initial formation of rhenium disulphide and its subsequent spreading.

The electronic structure of calix[4]arene phosphine oxides (CPO) and thiacalix[4]arene phosphine oxides (TCPO) is studied by X-ray photoelectron and emission spectroscopy and quantum chemical methods. The electron density distribution over atoms contained in CPO and TCPO is analyzed. The structure of higher occupied molecular orbitals (HOMO) is examined. It is shown that HOMOs of these compounds mainly consist of contributions of oxygen 2p atomic orbitals (AOs) of phosphoryl and hydroxyl moieties and also bridging sulfur 3p AOs, which indicates the bifunctionality of the considered extractant molecules. The mutual effect of the lower and upper rims of CPOs and TCPOs as well as the effect of their structures on the electron density distribution over calixarene molecules is investigated.

The electronic structure of hexanuclear Mn(II,III) pivalate complexes with tetrahydrofuran and isonicotinamide are studied by X-ray photoelectron spectroscopy and X-ray emission spectroscopy. It is shown that when isonicotinamide substitutes for tetrahydrofuran the spin state of manganese ions is retained; the electron density increases on the manganese and oxygen atoms of the [Mn 6 (O) 2 Piv 10 ] core.

The electronic structure of binuclear niobium complexes [Nb2S4(acac)4] and K4[Nb2S4(ox)4] is studied by X-ray emission fluorescent spectroscopy and quantum chemistry techniques. Data on the partial atomic composition of highest occupied molecular orbitals of the complexes are obtained. The energy positions of bonding and antibonding frontier molecular orbitals observed in the X-ray emission spectra of binuclear [Nb2((S2)2–)2]4+ clusters are determined by the analysis of overlap populations.

The study of the electronic structure of H2Pc was carried out to examine the structure of the lowest unoccupied molecular orbitals (LUMO) of molecule phthalocyanine by X-ray absorption spectroscopy using quantum-chemical calculations. The theoretical calculations were performed on the stationary theory (frozen orbital approximation, Z+1 model) and time-dependent density functional theory (TDDFT). A consideration of K edges absorption spectra of carbon and nitrogen in the common scale of binding energies allows estimating the contributions of AO of all phthalocyanine atoms to the LUMO, defining the sequence of levels, the binding energies of the corresponding levels, and also the character of electronic interactions between individual atoms. It was shown that the best agreement between the experimental and theoretical pre-edge structures of the absorption spectra of nitrogen and carbon for H2Pc is observed in the case of the application of stationary density functional theory in Z+1 model to account for an X-ray hole. In this case the 2p π AO of the Nα(1,2) and Сα atoms make a predominant contribution to the LUMO. The 2p π AO of the Nα(1,2) atoms mainly contribute to the boundary LUMO with the energy ~–2.3 eV.

Interpretation of X-ray photoelectron spectra (XPS) for p-nitroaniline and the nitroxide radical was carried out by the time-dependent density functional theory (TD-DFT) method using the (Z+1) N–1 approximation. Consideration of satellite transitions in the interpretation of the XPS spectra leads to good agreement with experiment. The shape of the X-ray photoelectron spectra of the radicals mainly depends on the relaxation processes caused by the X-ray hole screening effect and leading to the formation of satellite lines. The structure of the satellites in the XPS spectra depends on the spin state of the system and intermolecular interaction.

The electronic structure of free radicals and Cu(II) complexes with the nitronyl nitroxide radical and aminonitrone is studied by X-ray photoelectron spectroscopy (XPS). N1s XPS spectra of nitrogen atoms of Cu(II) complexes with aminonitrones confirm the diamagnetic nature of the ligands. The binding energies of the main peak and the intense satellite structure in the Cu2p (3/2,1/2) spectra of the complexes under study correspond to the Cu(II) state. The structure of the satellite in the Cu2p (3/2,1/2) spectrum depends on the environment of the metal ion.

На примере п-нитроанилина и нитроксильного радикала проведена интерпретация РФЭ спектров методом TD-DFT в приближении (Z+1)N–1. Учет сателлитных переходов при интерпретации РФЭ спектров приводит к хорошему согласию с экспериментом. Форма рентгеновских фотоэлектронных спектров радикалов в основном зависит от релаксационных процессов, обусловленных эффектом экранирования рентгеновской дырки и приводящих к образованию сателлитных линий. Строение сателлитных структур в РФЭ спектрах зависит от спинового состояния системы и межмолекулярного взаимодействия.

In the work X-ray K edges of chromium dichalcogenides CuCr 1- x M x ′ S 2 (M = V, Fe; x = 0-0.40) and MCrX 2 (M = Cu, Ag, Na; X = O, S, Se) were studied experimentally and theoretically. Comparison of fine structures of experimental XANES spectra obtained using a synchrotron radiation source and theoretical absorption spectra modelled using FDMNES software package allows one to study the influence of types of intercalate M, chalcogene X and also the effect of the cation substitution of chromium atoms by vanadium and iron on XANES structure of K edges in CuCr 1- x M x ′ S 2 and MCrX 2 .

The charge state of calix[4]arene thioethers and their complexes with palladium was studied by X-ray emission spectroscopy and X-ray photoelectron spectroscopy. Experimental data were compared with the results of quantumchemical calculations. The involvement of the sulfur lone electron pairs in the coordination to Pd atoms causes a decrease in the energies of the corresponding MOs having contributions from the sulfur 3p AOs and, consequently, a decrease in the intensity of the maximum A on going from the S( K β) spectra of free ligands to the spectra of complexes. The binuclear nature of the complexes does not lead to the onset of significant additional interactions between two metal centers.

X-ray emission and photoelectron spectroscopy and quantum chemical calculations are applied to study the electronic structure of H 2 Pc. A comparative analysis of the experimental and theoretical data of the energy spectrum and the partial composition of HOMO for phthalocyanine is performed. It is shown that the H 2 Pc HOMO is mainly composed of carbon 2 p π AO — Cγδ. The best agreement between the experimental partial density distribution in HOMO and the theoretical one is observed for the calculation by the density functional method in the Z+1 approximation. The DFT-ZORA method with LB94 model functional and the QZ4P basis set enables a high-accuracy calculation of the energies of 1 s levels of non-equivalent atoms in H 2 Pc relative to each other.