Applications of Raman Spectroscopy to Inorganic Chemistry

ＡｐｐｌｉｃａｔｉｏｎｓｏｆＲａｍａｎＳｐｅｃｔｒｏｓｃｏｐｙｔｏＩｎｏｒｇａｎｉｃＣｈｅｍｉｓｔｒｙＲｏｂｉｎＪＨＣｌａｒｋＦＲＳ（ＣｈｒｉｓｔｏｐｈｅｒＩｎｇｏｌｄＬａｂｏｒａｔｏｒｉｅｓＵｎｉｖｅｒｓｉｔｙＣｏｌｌｅｇｅＬｏｎｄｏｎ２ＯＧｏｒｄ...     

Ferric Nitrate/Molibdatophosphoric Acid as a New and Efficient System in the Oxidative Deprotection of Trimethylsilyl Ethers to Corresponding Carbonyl Compounds under Solvent‐Free Conditions

Oxidative deprotection of a variety of trimethylsilyl ethers were performed by Fe(NO₃)₃.9H₂O in the presence of H₃PMo₁₂O₄₀.xH₂O as catalyst at room temperature in good to high yields under solvent‐free conditions.     

SERS技术研究电化学中的共吸附

ＳＥＲＳ技术研究电化学中的共吸附顾仁敖（苏州大学化学系苏州２１５００６）ＳＥＲＳＳｔｕｄｉｅｓｏｎＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＣｏａｄｓｏｒｐｔｉｏｎＧｕＲｅｎａｏ（ＤｅｐａｒｔｍｅｎｔＣｈｅｍｉｓｔｒｙ，ＳｕｚｈｏｕＵｎｉｖｅｒｓｉｔｙＳｕｚｈｏ...     

Molecular Organometallic Chemistry on Surfaces: Reactivity of Metal Carbonyls on Metal Oxides

Metal carbonyls react on metal oxide surfaces to give a wide range of structures analogous to those of known compounds. The reactions leading to formation of surface-bound metal carbonyls are explained by known molecular organometallic chemistry and the functional group chemistry of the surfaces. The reaction classes include formation of acid-base adducts as the oxygen of a carbonyl group donates an electron pair to a Lewis acidic center; nucleophilic attack at CO ligands by basic surface hydroxyl groups or O^2? ions; ion-pair formation by deprotonation of hydrido carbonyls to give carbonylate ions; interaction of bifunctional complexes with surface acid-base pair sites such as [Mg^2⊕O^2?]; and oxidative addition of surface hydroxyl groups to metal clusters. The reactions of surface-bound organometallic species include redox condensation and cluster formation on basic surfaces (paralleling the reactions in basic solution) as well as oxidation of mononuclear metal complexes and oxidative fragmentation of metal clusters by reaction with surface hydroxyl groups. Most supported metal carbonyls are unstable at high temperatures, but some, including osmium carbonyl cluster anions on the basic MgO surface, are strongly stabilized in the presence of CO and are precursors of catalysts for CO hydrogenation at 550 K.     

Rhenium carbonyl complexes with monodentate-coordinated diphosphines: activation of terminal phosphino groups towards amine-oxide oxidation

Terminal phosphino groups of [Re₂(CO)₉(η¹-P-P)] (P-P = diphosphines) are activated towards oxidation by Me₃NO. The respective reactions of Me₃NO with [Re₂(CO)₉{η¹-P(o-anisyl)₂(CH₂)₃PPh₂}], [Re₂(CO)₉{η¹-PPh₂(CH₂)₃P(o-anisyl)₂}] and [Re₂(CO)₉(η¹-trans-PPh₂CHCHPPh₂)] were studied to investigate the mechanism of this oxidation. The results are consistent with an intramolecular pathway involving a cyclic intermediate, without exchange of the coordinated and terminal phosphino groups. A mechanism which involves an interaction of the terminal phosphino group with a carbonyl ligand is proposed. In sharp contrast to eq-[Re₂(CO)₉(η¹-P-P)] (P-P = Ph₂P(CH₂)_nPPh₂, n = 1-6), eq-[Re₂(CO)₉(η¹-trans-PPh₂CHCHPPh₂)] appears to be indefinitely stable towards equatorial → axial isomerization at room temperature, thus, allowing its crystal structure to be determined.     

Vibrational spectral studies of L-citrullinium perchlorate

Infrared and Raman spectra of L-citrullinium perchlorate crystals have been recorded at room temperature. The vibrational assignments of the observed wavenumbers are proposed on the basis of group theoretical analysis. The presence of carbonyl group indicates that the molecule exists in the ionic form. The shifting of stretching and bending wavenumbers indicates the presence of extensive hydrogen bonding in the crystal. The anion fundamentals however continue to be degenerated. This suggests that its symmetry is not affected in the crystal.     

Role of Hydrogen Migrations in Carbonyl Peroxy Radicals in the Atmosphere

Carbonyl peroxy radicals (RC(O)O₂) are the ubiquitous radical intermediates in the atmospheric oxidation of volatile organic compounds. In this work, theoretical studies are carried out to explore the role of the unimolecular H-migration in the carbonyl peroxy radicals by using quantum chemistry and kinetics calculations. The results showed that H-migration could be significant in the atmosphere at least in CH₃CH₂CH₂C(O)O₂ and (CH₃)₂CHCH₂C(O)O₂ with rates of ∽0.012 and ∽0.58 s^?1 at 298 K. Subsequent reactions of CH₃CHCH₂C(O)OOH would lead to the products with multi-functional groups, which might affect the aerosol formation process; while (CH₃)₂CCH₂C(O)OOH would transform to formaldehyde and acetone in a few steps. These processes would be important for the atmospheric modelling of volatileorganic compounds under low-NO_x conditions.     

Physical properties of ZnS thin films prepared by chemical bath deposition

Zinc sulphide thin films are deposited on SnO₂/glass using the chemical bath deposition technique. X-ray diffraction and atomic force microscopy are used to characterize the structure of the films; the surface composition of the films is studied by Auger electrons spectroscopy, the work function and the photovoltage are investigated by the Kelvin method. Using these techniques, we specify the effect of pH solution and heat treatment in vacuum at 500 °C. The cubic structure corresponding to the (1 1 1) planes of β-ZnS is obtained for pH equal to 10. The work function (Φ_material − Φ_probe) for ZnS deposited at pH 10 is equal to −152 meV. Annealing at 500 °C increases Φ_m (by about 43 meV) and induces the formation of a negative surface barrier. In all cases, Auger spectra indicate that the surface composition of zinc sulphide thin films exhibits the presence of the constituent elements Zn and S as well as C and O as impurity elements.