摘要:

Two dimensional HETCOR and long range HETCOR experiments were performed on a series of natural alkaloids which allowed complete1H and13C spectral assignments to be made. Protonproton and proton-carbon coupling constants are also given. Several errors in the literature are corrected.

ISSN:0038-7010    

DOI:10.1080/00387019008054474

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

It is frequently found that when various organic materials are pyrolyzed at temperatures in excess of about 550°C, the infrared spectra of the chars assume a similar, almost identical profile. That would indicate that the chars had become almost or completely spectroscopically and chemically indistinguishable and unrelatable to their precursors. This topic and the possible mechanisms involved are described in detail elsewhere [1].

ISSN:0038-7010    

DOI:10.1080/00387019008054475

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Emission spectra of the (B-X), (C-X) and (D-X) band systems of HgCl-radical and mercury atomic lines from highly excited levels to various lower levels have been observed during collisions of N+and N+2ions and HgCl2/Hg2Cl2molecules at different laboratory kinetic energies of the projectile ions. Emission cross-sections of the most intense mercury atomic lines and the (C-X) band system of the HgCl-radicals, have been measured in the laboratory kinetic energy range of 100–900 eV.

ISSN:0038-7010    

DOI:10.1080/00387019008054476

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Silybin, silydianin and silychristin, the three major constituents of the crude extract ofSilybum marianum, were investigated by means of1H-NMR in [2H6]-acetone. Non selective, single-selective and doubleselective1H-NMR spin-lattice relaxation rates were measured and interpreted in terms of dipolarly interacting proton pairs. The motional correlation time was found in the range 0.50–0.60 ns for all compounds.

ISSN:0038-7010    

DOI:10.1080/00387019008054477

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Band-pass and Variable digital filters as well as Savitzky-Golay derivatization method have been investigated and compared with the method of selfdeconvolution. The combination of the band-pass filtering and least-squares band fit optimization technique has been proposed as an efficient tool of analysis of vibronically structured electronic absorption spectra of inorganic compounds.

ISSN:0038-7010    

DOI:10.1080/00387019008054478

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

An unusual hindered rotation of an unsubstituted phenyl group in the drug, ketazolam, has been found at ambient temperature. Variable temperature lH NMR has been employed to examine the two- fold rotation about the C(sp2)-C(sp3) bond. Chemical shift as- signments of the IH NMR spectra and partial assignments of the13C spectra are supported by off-resonance decoupling, gated decou- pling, and low temperature 2Dl3C-1H heteronuclear chemical shift correlation experiments at 200.1 MHz for IH and 50.3 MHz for13C.

ISSN:0038-7010    

DOI:10.1080/00387019008054479

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Adirect method for determination of phenylepherine hydrochloride in presence of chlorapheneramine maleate, sulphacetamide or prednisolone acetate was achieved by first derivative (dA/dλ), delta absorption (ΔA) and first derivative of the delta absorption. (dΔA/dλ), spectrophotometric techniques applying “Zero-Crossing” technique of measurement.

ISSN:0038-7010    

DOI:10.1080/00387019008054480

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Arrays of Franck-Condon factors q(v′,v″) and r-centroidsr(v′,v″) were computed using Morse potentials for C1Π ‒ X1Σ+gand B O+u‒ X1Σ+gbands of the107Ag109Ag molecule.

ISSN:0038-7010    

DOI:10.1080/00387019008054481

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The simultaneous analysis of nuclear relaxation behaviour of119Sn-1H and117Sn-1H dipolar vectors from the proton spinlattice relaxation rates of the relative satellite peaks may yield a very accurate calculation of correlation times. The dipolar interaction between the proton and the bound tin nucleus is differently observed on the119Sn and117Sn satellite resonances in the1H partially relaxed spectra. Provided that the internuclear proton - tin distance is known, from the difference of the relaxation rate of the lH-118Sn signal with those measured from its satellite peaks, the correlation time can be calculated from the two independent set of data.

ISSN:0038-7010    

DOI:10.1080/00387019008054482

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The Pd(II) and Pt(II) complexes with two dibasic tridentate ligands viz. o-vanillin thiosemicarbazone and o-vanillin-4-phenylthiosemicarbazone, have been synthesized and characterized on the basis of their elemental analysis, magnetic susceptibility, conductance, ir and electronic spectral and thermogravimetric data. The presence of chlorine atom in the coordination sphere imparts a square planar geometry to these complexes having the general formula [M (L) Cl]. The mixed ligand complexes of the type [M (L) py. H2O] have also been prepared employing pyridine as an additional heterocyclic base. The complexes are square pyramidal and the presence of chlorine, water molecules is revealed by the study of their thermograms supported by the presence of relevant bands in their ir spectra. Suitable structures have been assigned to these binary and ternary complexes.

ISSN:0038-7010    

DOI:10.1080/00387019008054483

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor