ISSN:0030-4921    

DOI:10.1002/mrc.1270061016

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

ISSN:0030-4921    

DOI:10.1002/mrc.1270061017

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

AbstractThe CH proton NMR spectra of the twenty conceivable methyl and ethyl substituted hydrazines are presented and analyzed with respect to effects on chemical shifts of the CH protons caused by replacement of hydrogen by methyl and ethyl groups on the CNNC chain. Thirteen different methyl substituent effects and six different ethyl substituent effects are identified and evaluated. Most of the effects are shielding and in accordance with an electron‐releasing inductive effect of alkyl groups. A deshielding effect (the ‘CC bond effect’) is observed when a methyl group replaces the hydrogen on the carbon bearing the hydrogen in focus and primary hydrogen on the carbon bearing the hydrogen in focus and primary hydrogens become secondary, as observed in other systems. On the basis of their effects on the chemical shifts of methyl protons in CH3X, eighteen different hydrazyl groups (× = NR1NR2R3) fall into three classes: I (R1= H; R2, R3= H or alkyl); II (R1= alkyl; R2and/or R3= H); III (R1, R2and R3= alkyl), with slightly different electronegativities: 2·94, 2·83

ISSN:0030-4921    

DOI:10.1002/mrc.1270061002

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

AbstractLa configuration de divers époxydes conformationnellement homogènes en série bicyclo‐(n.3.0) alcaniquetransest établie par compléxation progressive avec avec Eu(dpm)3. Les exemples décrits mettent en évidence l'importance de cette technique qui est très supérieure à tous les autres procédés physico‐chimiques déjà mis en oeuvre pour déterminer la configuration des époxydes en s

ISSN:0030-4921    

DOI:10.1002/mrc.1270061003

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

AbstractThe chemical shifts of the aldehydic proton in furfural, thiophenealdehyde and benzaldehyde have been measured in fourteen solvents. The correlation of the chemical shifts of thiophenealdehyde and benzaldehyde is excellent (r= 0·996) while it is lower for furfural–benzaldehyde (r= 0·956). The long range coupling constantJα5of furiurai has been measured in twelve solvents and the rotameric mole fractions determined. The chemical shifts of individual rotamers are calculated and shown to correlate with benzaldehyde, (r= 0·992; 0·993). Only one rotamer is predominant for thiophenaldehyde in all solvents. The intrinsic solvent effects of the three aldehydes are s

ISSN:0030-4921    

DOI:10.1002/mrc.1270061004

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

AbstractLa combinaison de l'étude directe des spectres de RMN du proton et des déplacements induits par le complexe Eu(fod)3a permis d'étudier les phénomènes d'isomériesyn‐anti(Z‐E) dans un certain nombre d'imines cycliques et acycliques. Un cas d'équilibrationsyn⇌antipar addition d'Eu(fod)3a pu être mi

ISSN:0030-4921    

DOI:10.1002/mrc.1270061005

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

Abstract1H NMR spectra of photodimers of cinnamic acid, chalcone and related compounds were analysed, and the spectral parameters and all the coupling constants were obtained. A clear differentiation among the head‐to‐head and head‐to‐tail stereoisomers can be obtained by considering the values ofK,L,MandNparameters. The different types of hh and ht isomers can be immediately assigned by considering the relative values of the three‐bond couplings. An authentic example of an A2B2spin system is

ISSN:0030-4921    

DOI:10.1002/mrc.1270061006

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

AbstractLe spectre protonique ainsi que les satellites du carbone‐13 du propyne orienté dans un solvant nématique permettent d'accéder à la structure complète de cette molécule. L'accord avec les résultats obtenus par spectroscopie micro‐onde est

ISSN:0030-4921    

DOI:10.1002/mrc.1270061007

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

Abstract13C chemical shifts and13C205Tl spin–spin coupling constants are reported for phenylthallium(III) bis(trifluoroacetate) and some of its mono‐ and dimethyl derivatives. The signs ofnJ(13C,205Tl) relative ton+1J(1H,205Tl) are determined by offresonance decoupling of pr

ISSN:0030-4921    

DOI:10.1002/mrc.1270061008

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY

摘要:

AbstractThe high temperature13C NMR spectra of the methyl esters of deuteroporphyrin‐IX and protoporphyrin‐IX, and octaethylporphyrin show sharp discrete signals for the inner macrocycle carbon resonances. The temperature dependence of these shifts is discus

ISSN:0030-4921    

DOI:10.1002/mrc.1270061009

出版商:John Wiley&Sons Limited    

年代:1974

数据来源: WILEY