ISSN:0030-4921    

DOI:10.1002/mrc.1270070812

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractData derived from the carbon‐13 NMR spectra of 37 organic polychloro compounds allow one to identify readily the CHCl2, CCl2 and CH2Cl groups, the13C signals of which are registered in the shift ranges of 67 to 78 (80), 85 to 96 and 38 to 55 (59) ppm (from TMS), respectively, and have the distinctive one bond spin‐spin coupling constants1J(CH) 170 to 184 Hz (for the CHCl2groups) and 147 to 158 Hz (for the CH2Cl groups). The CCl2CH2CH2Cl fragment features characteristic diamagnetic shieldings of the CCl2 and CH2Cl that may be related to increased electron densit

ISSN:0030-4921    

DOI:10.1002/mrc.1270070802

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractUne analyse complète des spectres RMN de désoxy‐6 L‐hexopyrannoses de configuration α et des anomères β correspondants est réalisée. L'ensemble des paramètres obtenus confirme l'existence d'une structure chaise 1C (L) présentant une disposition axiale du substituant anomère dans le cas des α‐fuco‐, α‐rhamno‐ et α‐chinovopyrannosides de méthyle et des chlorures de α‐fuco‐ et α‐rhamnopyrannosyle. La structure reste de type chaise 1C (L) dans le cas des β‐fuco‐ et β‐chinovopyrannosides de méthyle. Il en est de même en dépit de I'effect anomère dû à I'atome de chlore, pour les chlorures de β‐fuco‐et β‐rhamnopyrannosyle. Par contre les paramètres RMN du chlorure de β‐chinovopyrannosyle ne semblent interprétables ni sur la base d'une g

ISSN:0030-4921    

DOI:10.1002/mrc.1270070803

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractThe carbon‐13 spectra of someparaandmetasubstituted phenylferrocenes have been analysed. The substituent‐caused shifts are discussed and compared with similarly substituted biphenyls. Correlations with Hammett parameters and with the reactivity parameters of Swain and Lupton have been attemp

ISSN:0030-4921    

DOI:10.1002/mrc.1270070804

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractL'analyse des spectres RMN à 250 MHz de tribromo‐2,3,6 méthyl‐4 cyclohexanones a permis de déterminer avec précision les constantes de couplageJ(HH) de ces composés. La validité des attributions a été contrôlé en reconstituant les spectres par calcul électronique. Les résultats observés ont été interprétés en terme de d

ISSN:0030-4921    

DOI:10.1002/mrc.1270070805

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

Abstract29Si,14N13C and1H NMR data are presented for a series of homologous (methylethoxysilyl)alkylamines of the type (CH3)3−n(C2H5O)nSi(CH2)mNH2(n=o to 3;m= 1 to 4). The measured13C and1H chemical shifts correlate with the total net chargesQAon the corressponding atoms, estimated by the Del Re method.14N and29Si chemical shifts which do not show simple linear relationships to the charges are found to correlate with the relative basicities of the compounds. The influence of the remote substituent (NH2and others) on the29Si chemical shifts is shown to depend on the number and nature of substituents directly on the silicon atom. Argyments for d‐orbital participation in the SiO bounds are given. The chemical shifts of29Si,14N and13C nuclei are not consistent with the fromation of intramolecular ‘long bonds’ between the solicon and nitrogen atoms in aliphatic silym

ISSN:0030-4921    

DOI:10.1002/mrc.1270070806

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractLa résonance magnétique nucléaire du proton à basse température s'est révélée peu fructueuse dans l'étude conformationnelle des benzophénones substituées. Cependant, l'analyse des déplacements induits par les lanthanides nous a permis de recouper de façon très satisfaisante les résultats obtenus par diffusion Rayleigh dépolarisée et dipolemétrie pour les benzophénonesmetaetorthosubstituées. L'existence en solution d'un équilibre conformationnel pour ces co

ISSN:0030-4921    

DOI:10.1002/mrc.1270070807

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractAllJ(PH) andJ(PC) values, including signs, have been obtained in acetylenic and propynylic phosphorus derivatives, R2P(X)CCH and R2P(X)CCCH3(X  oxygen, lone pair and R  C6H5, N(CH3)2, OC2H5, N(C6H5)2, Cl) from1H and13C NMR spectra. In PIVderivatives the following signs are obtained:1J(PC)+,2J(PC)+,3J(PC)+,3J(PH)+,4J(PH). Linear relations are observed between1J(PC),2J(PC) and3J(PC) versus3J(PH), indicating that these coupling constants are mainly dependent on the Fermi contact term, though the other terms of the Ramsey theory do not seem to be negligible for1J(PC) and2J(PC).In PIIIderivatives these signs are:1J(PC)‐ and +,2J(PC)+,3J(PC)‐,3J(PH)‐,4J(PH)+. Only3J(PC) and3J(PH) reflect a small contribution of the Fermi contact term while in1J(PC) and2J(PC) this contribution seems to be negligi

ISSN:0030-4921    

DOI:10.1002/mrc.1270070808

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractThe preparation, characterisation and1H NMR spectra of someN‐arylaminopropenylylidenearylammonium salts are reported. The NMR data show that in DMSO the cations exist as conjugated amino–imines, generally as the ‘all‐trans’ geometrical isomer. An exception is found in the case of the 4‐nitrophenyl derivative which produces a mixture of the ‘all‐trans’ and ‘cis‐trans’ isomers with slow exchange between them at room temperature. The relative stability of the ‘all‐trans’ isomer increases as the salt becomes more ionic. By varying the temperature, pH and nature of the anion it is found that exchange of the NH protons on the cation controls the appearance of spin‐spin coupling betwee

ISSN:0030-4921    

DOI:10.1002/mrc.1270070809

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractAnalysis of the noise decoupled13C spectra of doubly13C labelled compounds where the two labelled carbons are identical, makes the determination of reltive signs of13C13C coupling constants possible in a very simple way. The involved carbon form AA'X or AA'B spin system

ISSN:0030-4921    

DOI:10.1002/mrc.1270070810

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY