An investigation of terpene hydrocarbons of the carane series by photoelectron spectroscopy

2- and 3-Carenes and carane have been studied by PE spectroscopy. On the basis of an analysis of orbital interactions and information obtained from the PE spectra of model compounds an assignment has been made of the bands corresponding to ionization from the molecular orbitals of the double bond and of the cyclopropane ring.Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. A. A. Zhdanov Scientific-Research Institute of Physics at Leningrad State University, Leningrad. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 639–644, September–October, 1985.     

Surface ionization of terpene hydrocarbons

By means of a surface ionization indicator for traces of materials in the atmosphere it has been established that many natural materials containing terpenes and their derivatives are ionized on the surface of heated molybdenum oxide at atmospheric air pressure. A mass-spectrometer method has been used to explain the mechanism of ionization of individual terpene hydrocarbons and to establish its principles. The ionization of -pinene, alloocimene, camphene, and also adamantane on oxidized tungsten under vacuum conditions has been investigated. The -pinene and alloocimene are ionized by surface ionization but camphene and adamantane are not ionized under vacuum conditions. The surface ionization mass spectra of -pinene and alloocimene are of low line brightness in comparison with electron ionization mass spectra and differ between themselves. The temperature relations for currents of the same compositions of ions during ionization of a-pinene and alloocimene are also different, which leads to the possibility of surface ionization analysis of mixtures of terpenes being ionized. The ionization coefficients of alloocimene and -pinene on oxidized tungsten under temperatures optimum for ionization and the ionization potentials of alloocimene molecules and of radicals (M-H) of both compounds have been evaluated. The routes of monomolecular decompositions of metastable vibrationally excited ions have been followed. An explanation has been given for the difference in ionization capacities of different terpenes and the possibility of surface ionization of many hydrocarbons of a certain structure has been considered.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 2, pp. 180–188, March–April, 1986.     

Transformations of epoxyketones of the carane series using bases

Conclusions -3,4-Epoxycarane-2,5-dione when treated with alcoholates and alkali in alcohol forms 3,6,6-trimethyl-2-oxobicyclo[3. 1. 0]-3-hexen-4-yl-formic acid and-3,4-epoxycaran-2-on-5-ol, whereas in dioxane the first product is formed exclusively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 677–679, March, 1984.     

系列二羰基化合物的HeI紫外光电子能谱(UPS)及量子化学研究

报道了醌及苯并酸酐等系列二羰基化合物的气相HeI紫外光电子能谱。对各体系利用Gaussian94程序RHF/3-21G进行了构型优化,对得到的优势构型采用STO-6G基组进行了轨道计算。并结合计算结果对各分子体系的UPS谱进行了分析指认。计算结果分析显示:标题化合物的第一个电离峰均是由苯环部分的共轭π键电子电离及羰基的孤对电子电离引起的,且化合物的IP~1值随羰基在HOMO轨道中权重的增大而增大。各化合物的第二、三谱带都与羰基不同类型的孤对电子峰相关联。说明羰基为此类化合物的特征基团。且分子的对称性越高,羰基的孤对电子峰n^-和n^+的平均值越大,分裂值也越大。     

Surface-ionization mass spectrometry of terpene hydrocarbons

The surface ionizations of four terpene hydrocarbons (-pinene, alloocimene, ³-carene, and limonene) on oxidized tungsten wires and ribbons have been investigated. The mass spectra of the ions and the temperature dependences of the currents have been obtained, current densities have been estimated, and monomolecular decompositions of the metastable vibrationally excited ions have been found. The actions on the surface of oxidized tungsten leading to the formation of ionizing particles are considered. The ionizing potentials of the radicals (M - H) obtained on the splitting out of hydrogen atoms from the molecules have been estimated.A. F. Ioffe Physicotechnical Institute, USSR Academy of Sciences, Leningrad. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 483–488, July–August, 1989.     

Surface-ionization mass spectrometry of terpene hydrocarbons

The surface ionizations of four terpene hydrocarbons (α-pinene, alloocimene, Δ³-carene, and limonene) on oxidized tungsten wires and ribbons have been investigated. The mass spectra of the ions and the temperature dependences of the currents have been obtained, current densities have been estimated, and monomolecular decompositions of the metastable vibrationally excited ions have been found. The actions on the surface of oxidized tungsten leading to the formation of ionizing particles are considered. The ionizing potentials of the radicals (M - H) obtained on the splitting out of hydrogen atoms from the molecules have been estimated.     

Theoretical and experimental X-ray photoelectron spectroscopy investigation of ion-implanted nafion

The membrane properties of a Nafion surface can be modified by ion implantation with N⁺ or F⁺. The results are presented of an X-ray photoelectron spectroscopy (XPS) study of implanted surfaces. For the interpretation of the XPS spectra, calculations using a semiempirical quantum chemical formalism (AM1) have been applied, in conjunction with a charge-potential model, to predict the C_1s core electron binding energies. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 551–556, 2004     

Anion photoelectron spectroscopy and density functional investigation of vanadium carbide clusters

The influence of source conditions on vanadium-carbon cluster formation in a methane-vanadium plasma is explored and analyzed by photoelectron spectroscopy, revealing that the metal-carbon ratio has substantial influence over the cluster products. Experiments that employ large methane content produce carbon-rich mono- and divanadium carbides. The carbon-rich clusters show a preference for the formation of cyclic neutral and linear ionic structures. When the methane concentration is decreased, VmCn clusters are formed with m = 1-4 and n = 2-8. The photoelectron spectra of clusters formed under these conditions are indicative of a three-dimensional network. We have measured a significantly lower vertical electron affinity for the VC2, V2C3, and V4C6 clusters compared with proximate species. Interestingly, the VC2 species is a proposed building block of the M8C12 Met-Car cluster, and the 2,3 and 4,6 clusters correspond to the 1/4 and 1/2 Met-Car cages, respectively. This correlation is taken as evidence of their importance in the formation of the larger Met-Car species. These results are supported by density functional theory (DFT) calculations carried out at the PBE/GGA level.     

An investigation in the isoxazole series

The hydrogen atoms in the CH₃ groups in position 5 of 3,5-dimethyl-4-nitroisoxazole (I) and 3,5-dimethyl-4-phenylazoisoxazole (II)undergo isotopic exchange with diethyl[D]amine. The position of entry of the deuterium has been established and the CH₃ groups of compounds I and II have been characterized by NMR spectroscopy. The possibility of a correlation of the reactivities of the methyl groups with their chemical shifts is discussed.For part XX, see [1].     

Correlations between photoelectron and uv absorption spectra of polycyclic hydrocarbons. The pyrene series

In continuation of earlier work on the relationships between the PE and optical spectra of polycyclic aromatic hydrocarbons, the PE spectra of 34 pyrene-type molecules are correlated with electronic spectra. As in other series of hydrocarbons considered so far, the p-band in the optical spectra is related to the first IP, whereas the α- and β-bands can be related to higher IP's. Regularities observed in the PE spectra of linearly annellated, plane- and centro-symmetrically annellated pyrenes are discussed.     

Site-sensitive X-ray photoelectron spectroscopy of Fe3O4 by photoelectron diffraction

Fe 2p core-level photoelectron spectra of magnetite were measured using soft X-ray and hard X-ray, and its emission angle dependence was investigated. The photoelectron diffraction pattern from different atomic sites differs because the atomic arrangement surrounding each site is different. By selecting the forward-focusing-peak (FFP) directions characteristic to each atomic site and measuring the kinetic energy dependence of the FFP intensities at the Fe 2p core-level range, we succeed in detecting the variation of the peak intensity of Fe 2p core-level spectra at different emission directions. This result, consistent with recent results, suggests that the lower-binding-energy peak of the Fe 2p core-level spectrum may be assigned as the B site component.     

Spectroscopic investigation of uranium sorption on soil surface using X-ray photoelectron spectroscopy

A study was carried out to understand the sorption of uranium (U) onto soil surface and identify the species of U on soil surface using X-Ray Photoelectron Spectroscopy (XPS). For the study soil was amended with uranyl nitrate and surface speciation study was carried out by investigating the energy region for U in spectrum. Analysis of spectrum revealed that U is present in U(VI) state. Deconvolution of XPS spectrum of U(VI) sorbed on soil surface revealed that U(VI) species such as, UO₂ ²⁺ and (UO₂)_x(OH) _y ^(2x?y)+ form complex with silanol, aluminol and goethite sites. The possible surface complexation is: ≡Al(OH)₂UO₂ ²⁺, ≡SiO₂UO₂, ≡SiO₂(UO₂)₃(OH)₅ and ≡Fe(OH)₂UO₂.     

Film thicknesses determined by X-ray photoelectron spectroscopy

The knowledge of the reduced thickness of overlayers in the thickness range up to 5 nm is a valuable contribution to quantitative analysis in XPS. A new method for its determination is described which can be applied to most of the commercially available instruments. The method considers influences like countrate statistics, surface roughness, thickness distribution, elastic electron scattering, divergence of the photoelectrons detected by the spectrometer and energy dependence of the inelastic mean free path of the electrons in matter. The reliability of the results is verified by XPS-measurements performed on SiO₂-layers on Si.Besides, the XPS-results obtained from Si₃N₄-layers on Si measured under different take-off angles demonstrate the applicability of this method for the investigation of film growth. A further aspect is given by the recognition of elastic electron scattering by a simplified expression no longer asking for Monte Carlo calculations.     

Synthesis of sulfide derivatives of the carane series by reactions of 3-carene oxides with functional mercaptans

The reaction of 3-carene oxides with functional mercaptans under the conditions of basic catalysis takes place regio- and stereoselectively and is a convenient method of obtaining polyfunctional derivatives of 3-carene and the products of their chemical transformations (hydroxyethylthiocaranols, carboxyalkylthiocarenols, carane thiolactones). Together with the products mentioned, a new type of bicyclic, terpenes — bis-hydroxycaranyl) sulfides — is formed in th3ese reactions.S. V. Kurashov Kazan' State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 193–198, March–April, 1991.     

Monitoring of liquid-phase organic reactions by photoelectron spectroscopy

There are strings attached: after linking the reacting groups to head groups of ionic liquids to drastically lower the vapour pressures of the reactants, ordinary liquid-phase organic reactions can be monitored by in situ X-ray photoelectron spectroscopy. This approach is demonstrated for the nucleophilic substitution of an alkyl amine and an alkyl chloride moiety, which are attached to the cation and anion of ionic liquids, respectively.     

Ionization potentials of some azoalkanes by photoelectron spectroscopy

Photoelectron spectra have been obtained for a set of azo compounds consisting of three pairs of cis, trans isomers, seven bridgehead substituted 2,3-diazabicyclo[2.2.2]oct-2-enes (DBO's), and one arylazoalkane. The lowest ionization potentials, which range from 7.83 to 9.21 eV, do not correlate with cis ground state energy or photolability of the DBO derivatives. Vibrational fine structure was observed in three DBO's, allowing verification that the lowest ionization takes place from the antibonding combination of nitrogen lone pairs.     

Correlations between photoelectron and ultraviolet absorption spectra of polycyclic hydrocarbons : The terrylene and peropyrene series

The photoelectron spectra of terrylene, peropyrene and their benzologues are studied and related to their optical spectra. The analogy to the perylene and pyrene series considered in earlier papers is perfect.