ISSN:0749-1581    

DOI:10.1002/mrc.1260290102

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

Abstract1H and13C NMR studies were carried out on 1‐ethenylnaphthalene, 2‐ethenylnaphthalene, 9‐ethenylanthracene, 9‐ethenylphenanthrene, 1‐ethenylpyrene and 1‐ethenylperylene. Assignments of proton and carbon resonances were made with the aid of 2D COSY, 2D HETCOR, 2D COLOC, 2D COLOCS,3J(H,C) INAPT, and NOE difference spectral

ISSN:0749-1581    

DOI:10.1002/mrc.1260290103

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe1H and13C NMR spectra of several saturated polynitropolycyclic molecules were unambiguously assigned using aromatic solvent‐induced shifts, NOE difference spectra,1H–1H COSY spectra and 2D13C–1H shift correlated spectra, optimized either for one‐bond or long‐range13C–1

ISSN:0749-1581    

DOI:10.1002/mrc.1260290104

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe complete assignment of all1H and13C NMR signals of acrihellin in chloroform solution is presented. The analysis of the1H and13C NMR spectra was performed using the heteronuclear 2D NMR techniques H,C‐COSY and H,C‐COLOC. For an unambiguous assignment of the13C NMR spectrum the elucidation of carbon–carbon connectivities via 2D‐INADEQUATE was most important. The INADEQUATE experiment was also applied to hellebrigenin in DMSO‐d6solution. This experiment confirmed a recently published carbon a

ISSN:0749-1581    

DOI:10.1002/mrc.1260290105

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractOne‐dimensional COSY is shown to be a promising technique for the detection of small, unresolved proton‐proton coupling constants. Under certain circumstances the method can be more effective than two‐dimensional phase‐sensitive COSY. A detailed analysis of the experimental conditions is presented. The possible application of the method in oligosaccharide sequencing is outlined. Another potential use of one‐dimensional COSY is in the evaluation of coupling constants in macromolecules. In this case the efficiency of the polarization transfer is decreased owing to the fast transverse relaxation times of the protons. DISCO analysis was applied for the determination of coupling constants in unresolved m

ISSN:0749-1581    

DOI:10.1002/mrc.1260290106

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe1H NMR spectra of selected heptafulvenes 2a–e were analysed under high‐resolution conditions. The results are in agreement with a symmetrical boat conformation for 2a and with a nearly planar conformation of 2e. Within the series 2a–e, ring planarization and π‐delocalization increase. Substituent effects on NMR parameters are d

ISSN:0749-1581    

DOI:10.1002/mrc.1260290107

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe iron dihydride FeH2(PP3) [PP3= P(CH2CH2CH2PMe2)3] is fluctional, with the terminal co‐ordinated phos‐phine groups undergoing intramolecular exchange in addition to the iron‐bound hydrides. The exchange kinetics of the metal‐bound hydrides was examined using a magnetization inversion–transfer–recovery method, and the activation energy wasca. 64 kJ mol−1at 260 K. The effect of spin–spin coupling on the magnetization transf

ISSN:0749-1581    

DOI:10.1002/mrc.1260290108

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

Abstract1Hand 13C NMR studies ofN‐methyl‐substituted hydroxamic acids, RCON(CH3)OH (R = CH3, C2H5and C6H5), show that the series exhibitscis–transisomerism about the CN bond. TheZ/Eratio increases in the series CH3

ISSN:0749-1581    

DOI:10.1002/mrc.1260290109

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractA one‐dimensional version of the heteronuclear multiple bond correlation experiment (HMBC) is shown to be an excellent alternative to the full two‐dimensional experiment when the carbon resonances are well resolved. The quaternary resonances of lambertellin, a metabolite ofCiboria gordoniiFunk, are correlated to the previously assigned proton resonances by selective transfer of zero and double quantum coherence to observable proton magnetization by a frequency‐selective carbon decoupler

ISSN:0749-1581    

DOI:10.1002/mrc.1260290110

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo‐ and three‐bond deuterium isotope shifts (2Δ and3Δ) of the13C nuclear shielding were measured for a series ofpara‐substituted anilines and acetanilides, in which the amide NH or the amine NH2hydrogens were partially exchanged with deuterium. The results show that when strong electron‐donating groups are present at theparaposition in acetanilides, the2Δ(C‐1) isotope shifts are smaller than the3Δ(C‐2,6) isotope shifts. Empirical correlations that relate2Δ isotope shifts with1H(NH),13C(C‐ipso),15N(NH2or NH),17O(CO) NMR chemical shifts and with3Δ isotope shifts are presented. The results are interpreted in each series as depending on the characteristic nitrogen lon

ISSN:0749-1581    

DOI:10.1002/mrc.1260290111

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY