Simple isotopic product rules valid for absolute and integrated infrared intensities

Microwave spectra of CH¹⁸ OCOOH, CHOC¹⁸ OOH, CHOCO¹⁸ OH, ¹³ CHOCOOH and CHO¹³ COOH are reported and have been used in combination with data on CHOCOOH and CHOCOOD to determine the molecular structure as r(C=O)_ald. = 1.174 ± 0.006 Å, r(C=O)_acid = 1.203 ±0.006 Å, r(C—O) = 1.313 ± 0.010 Å, r(C—C) = 1.535 ± 0.005 Å, r(O—H) = 0.948 ± 0.004 Å, r(C—H) = 1.104 ±0.010 Å, ald. = 123.7 ± 0.4<, 相似文献   

Quaterthiophene-based dimers containing an ethylene bridge: molecular design,synthesis, and optoelectronic properties

Two quaterthiophene-based dimers including an ethylene bridge have been designed and efficiently prepared; experimental and computational studies show a promising potential as semiconducting material with a charge transport of higher dimensionality compared to quaterthiophene.     

Theory of ion neutralisation scattering from surfaces

A method for the calculation of the probability of neutralisation of an ion, which is scattered from the surface of a solid is presented. It assumes the ion to move along a classical trajectory and solves for the time evolution operator for the electronic system. For one electron Hamiltonians the solution can be carried out exactly. Results are presented for scattering from a semi-infinite linear chain.     

ScIII‐Doped Zeolites as New Heterogeneous Catalysts: Mukaiyama Aldol Reaction

Sc^III‐doped solids based on zeolite materials have been investigated for the first time as catalysts in organic synthesis. Sc^III–USY zeolite proved to be a novel and very efficient heterogeneous catalyst for the Mukaiyama aldol reaction. This easy‐to‐prepare catalyst exhibited wide scope and compatibility with functional groups and is very simple to use, easy to remove (by simple filtration), and is recyclable (up to three times without loss of activity).     

Strong ion-exchange centrifugal partition chromatography as an efficient method for the large-scale purification of glucosinolates

The glucosinolates sinalbin and glucoraphanin were purified by strong ion-exchange displacement centrifugal partition chromatography (SIXCPC). The optimized conditions involved the biphasic solvent system ethyl acetate/n-butanol/water (3:2:5, v/v), the lipophilic anion-exchanger Aliquat 336 (trioctylmethylammonium chloride, 160 and 408 mM) and a sodium iodide solution (80 and 272 mM) as displacer. Amounts as high as 2.4 g of sinalbin and 2.6g of glucoraphanin were obtained in one step in 2.5 and 3.5h respectively, starting from 12 and 25 g of mustard and broccoli seed aqueous extracts, using a laboratory scale CPC column (200 mL inner volume).     

A note on the intensities of N.M.R. absorption lines

A proof is given of the proposition that the intensity of the N.M.R. absorption line from a group of n equivalent protons is proportional to n. To do this, it has been necessary to satisfy the Pauli exclusion principle by classifying states according to the irreducible representations of the symmetric group. As far as spin is concerned, this classification is equivalent to one according to the value of I, the total spin. Degeneracy with respect to I, which would otherwise occur, is prohibited by the exclusion principle, and a correlation (not one-to-one) is established between I and the symmetries of the rotational states.     

Stimulated Raman investigation of CO2-laser-excited SF6

Stimulated Raman spectroscopy is used to probe the photoexcitation dynamics of CO₂-laser-excited SF₆ in a molecular free-expansion jet. Time-dependent depletion of rotational levels in the ground state is observed by monitoring the ν₁ Raman spectrum at various delay times after the CO₂-laser excitation pulse. Optical Stark shifts are also seen, at short delay times, arising from resonances of the IR laser pulse with ν₃ transitions from both ground and ν₁ = 1 states. Molecules excited to the ν₃ = 1 level are detected by scanning the ν₁ + ν₃ ? ν₃ hot band. A direct determination of the anharmonicity X₁₃ = ?2.910 ± 0.002 cm^?1 is thus obtained.