摘要:

SERS of a new kind of surfactant, diazafluorenone Schiff base amphiphile, were obtained on an Ag electrode at different potentials. Cyclic voltommetry measurements on the Ag electrode indicate a redox reaction was occured and the possibility of two kinds of orientations was discussed.

ISSN:0038-7010    

DOI:10.1080/00387019408007257

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The1H NMR spectra of racemic (erythro) methoxamine free base, 1,1-(1-aminoethyl)-2,5-dimethoxybenzenemethanol, have been studied at or near ambient temperatures in CDCl3or CD3CN with the added chiral lanthanide shift reagent (LSR), tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato] europium (III), 2. Spectrometers operating at 60, 200 and 300 MHz were employed; some COSY spectra were acquired to support assignments. Enantiomeric shift differences (Δ Δ Δ) were observed for several nuclei of 1 with added 2 in either CDCl3or CD3CN and an “anomalous” (upfield) shift was seen for the NCH signal. A high degree of signal broadening was seen for runs with either solvent, and surprising similarity was found for the slopes in plots of chemical shift versus [2]/[1] molar ratios for the different nuclei of 1 whether the hydrogen bond donor solvent (CDCl3) or the hydrogen bond acceptor solvent (CD3CN) was used. Together with the anomalous shift noted above, these results are interpreted as consistent with strong bidentate chelation of2by1.

ISSN:0038-7010    

DOI:10.1080/00387019408007258

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The electron gas heating at resonant light irradiation of hollow cathode discharge is measured. The possible channels of opttogalvanic transformation of the absorbed photons are compared and disscised.

ISSN:0038-7010    

DOI:10.1080/00387019408007259

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two protonated forms of chlorine nitrate, HClONO+2and ClONO2H+, are treatedab initioby the Hartree-Fock and the second order Møller-Plesset perturbation approach with the standard 6–31G* basis set. Both minimum energy structures are planar (C3symmetry) and their structural, energy, and vibrational parameters are reported. The computations conclude that the proton attacks the chlorine nitrate at its central, not end, oxygen atom. The protonation causes a considerable elongation of the central ON bond which becomes most probable place of cleavage. The dissociation should yield the neutral HOCl and NO+2. These quantum-chemical findings well agree with the previous experimental indications.

ISSN:0038-7010    

DOI:10.1080/00387019408007260

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This work presents the evaluation by empirically derived equations for the substituent effect (α, β, γ, δ) on the13C NMR chemical shifts for C-1, C-2, C-3 and C-4 in β-alcoxyvinylhalomethylketones 1a–h to 3a–h [R3C(O)-C(R2)=C(R1-OR, where R1= H, alkyl or phenyl, R2= H, alkyl or hetero-alkyl, and R3= di- or trihalomethyl], taking as reference the compound la. From the calculated values for the α, β, γ, δ effects for each substituent it was possible to estimate the chemical shift of each carbon of the compounds 1–3. The13C chemical shifts of the C-1, C-2, C-3, C-4 of these compounds, can be estimated with good to rasoable precision: 93% of the calculated chemical shifts are found to be within ±2.0ppm, and 100% are found to be within ±3.0ppm.

ISSN:0038-7010    

DOI:10.1080/00387019408007261

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

An intermediate compound, most likely enolic (A), was detected by13C-NMR spectroscopy during decarboxylation of 4-hydroxy-2H-1,2-benzothiazine-3-carboxylic acid 1,1-dioxide (I).

ISSN:0038-7010    

DOI:10.1080/00387019408007262

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0038-7010    

DOI:10.1080/00387019408007263

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor