bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon‐13 n.m.r. studies of purines and 8‐azapurines in basic aqueous medium
Authors: Purnell Linda Goodrich , Hodgson Derek J. 
Published: May 2005

AbstractThe 13C n.m.r. spectra of a variety of purines and 8‐azapurines have been studied in aqueous basic medium; the shifts were measured using dioxane as reference, and corrected to the TMS scale. The compounds studied include adenine, hypoxanthine, 6‐mercaptopurine, guanine, xanthine, 8‐azaadenine, 8‐azahypoxanthine, 8‐azaguanine, 8‐azaxanthine, and 2‐thio‐8‐azaxanthine. Resonances were assigned using noise‐decoupling, selective deuteration at the 8‐position of purines, and coupled spectra. The general effect of changing from a purine to its 8‐aza analog is to produce a downfield shift of C‐2, C‐5, and C‐6 and an upfield shift of C‐4.
Etude dans la Série Bicyclo [2.2.2]octanique: IV—Influence de l'Anisotropie Magnétique d'un Groupement Géminé Chloro‐Nitrile sur les Déplacements Chimiques des Protons des Bicyclo[2.2.2]octènes
Authors: Rouillard M. , Geribaldi S. , Damiano‐Gal J. , Azzaro M. 
Published: May 2005

AbstractL'analyse des spectres RMN 1H d'une série d'acétoxy‐1 ou 3 chloro‐6 cyano‐6 bicyclo[2.2.2]octènes‐2 et de chloro‐6 cyano‐6 bicyclo[2.2.2]octanones‐3 permet de déterminer l'anisotropie magnétique d'un groupment chloro‐nitrile géminé à l'aide de la relation de McConnell. Les résultats obtenus rendent possible l'attribution de la position endo ou exo des substituants CN et Cl par rapport à la double liaison ou au carbonyle pour ces composés et confirment les conclusions de la littérature relatives aux chloro‐5 cyano‐5 bicyclo[2.2.2]octènes‐2.
Dual substituent parameter analysis of the ethyl and ipso13C n.m.r. chemical shifts of some ring‐substituted ethylbenzenes and ethylnaphthalenes
Authors: Adcock William , Kitching William , Alberts Vince , Wickham Geoffrey , Barron Peter , Doddrell David 
Published: May 2005

AbstractThe natural abundance 13C n.m.r. spectra of a series of para‐substituted ethylbenzenes, 4‐substituted‐1‐ethylnaphthalenes and a limited series of 6‐substituted‐2‐ethylnaphthalenes have been examined at low dilution in deuterochloroform solvent. The ethyl carbons and Cipso in the phenyl series (i.e. have been assigned, and substituent chemical shifts for these carbons calculated and analysed by the Dual Substituent Parameter treatment. (Chemical shifts of all ring carbons have been obtained, but not assigned). Generally speaking, electron‐withdrawing substituents lead to positive (i.e. downfield) substituent chemical shifts for CH2 and negative substituent chemical shifts for CH3, i.e. ‘normal’ and ‘inverse’ behaviour respectively. Cipso in the phenyl series exhibits a ‘normal’ dependence. The dependences of the various substituent chemical shifts on inductive and resonance parameters are discussed, and compared with the behaviour of side chain carbons in other substituted benzene systems.
Stable conformations of N,N,N′,N′‐ tetraisopropylthiuram disulphide and monosulphide found in low temperature 1H N.m.r. spectra
Authors: Takeda Yu‐ichi , Matsuda Tsuneo , Tanaka Toshio 
Published: May 2005

Abstract1H N.m.r. spectra of N,N,N′,N′‐tetraisopropylthiuram disulphide and monosulphide in CS2 suggested that internal rotations both around the carbamate CN and isopropyl–nitrogen bonds are restricted at low temperatures. As a result, both compounds exist as two dl pairs of isomers with respect to rotation around the isopropyl–nitrogen bond. The spectra further suggest that one pair of the isomers is subdivided into two sets of dl pairs, possibly owing to the restriction of torsion of the two carbamate planes with respect to each other. Possible conformations of these three dl pairs of isomers are proposed, and the assignments of each proton signal are described.
1H n.m.r. conformational studies of glycyl‐L‐phenylalanine and L‐phenylalanyl‐glycine dipeptides and their complexes with palladium (II)
Authors: Kozlowski Henryk , Formicka‐Kozlowska Grażyna , Jeżowska‐Trzebiatowska Boguslawa 
Published: May 2005

AbstractThe conformations of Gly‐Phe and Phe‐Gly dipeptides and those of their complexes with the Pd(II) ion has been established by means of 1H n.m.r. spectra over various pH ranges. In the most stable rotamer of both dipeptides the bulkiest groups, i.e. carboxylate (or carbonyl) and the aromatic ring, are in trans position to each other. In the 1:1 molar ratio complexes, the dipeptides are the tridentate ligands within the 3–10 pH region. In the predominant conformer the aromatic ring lies over the complex plane, which suggests its interaction with the metal ion. At pH above 13, the carboxyl group becomes non‐coordinated. The dipeptides are then bidentate and the most stable rotamers are the same as those found for the metal‐free ligands, i.e. the carboxyl or carbonyl group is in the trans position to the aromatic ring. The glycine chelate ring in the Pd(II) Gly‐Phe complex is planar up to pH 10 and its distortion from planarity follows when the ligand becomes bidentate.
Some INDO perturbation calculations of nJ(NC) values
Authors: Khin Tun , Webb G. A. 
Published: May 2005

AbstractStandard INDO parameters are used in ‘sum‐over‐states’ perturbation calculations of nJ(NC) in a variety of molecular environments. Good agreement with the experimental data is, in general, obtained when the integral products SN2(o)SC2(o) and 〈r−3〉N〈r−3〉C assume the values of 35.167 a.u.−3 and 4.980 a.u.−3, respectively. For ‘pyridine‐type’ nitrogen atoms the major contribution to nJ(NC) usually arises from the orbital term whereas the contact term dominates the values of nJ(NC) for ‘pyrrole‐type’ and amino nitrogen atoms.
Rotational isomerism in 3‐mono‐oxygenated and 3,7‐di‐oxygenated derivatives of N‐acetyl‐17‐aza‐D‐homoandrost‐5‐ene
Authors: Dawson Philip J. , Crabb Trevor A. , Williams Roger O. 
Published: May 2005

AbstractThe 1H n.m.r. spectra of 3‐mono‐oxygenated and 3,7‐dioxygenated N‐acetyl‐17‐aza‐D‐homoandrost‐5‐enes show unequal populations of the amide rotational isomers in chloroform‐d1 solution. The populations are dependent upon the orientation of the C‐7 oxygen substituent but are independent of concentration. In pyridine‐d5 solution the two rotameric states for each compound are almost equally populated.
Stereochemical aspects of proton chemical shifts. VI—increments due to geminal hydroxyl, methyl substitution
Authors: Tavernier Dirk , Antunis Marc 
Published: May 2005

AbstractIn geminal methyl, hydroxyl substitution an axial hydroxyl, equatorial methyl arrangement has a downfield effect on a syn axial hydrogen atom which is larger by 0.3 ppm than an axial methyl, equatorial hydroxyl arrangement. It is proposed that these observations may constitute a basis for configurational assignment.
Déplacements Chimiques du Carbone 13, Constantes de Couplage 1J(CH) et 3J(CH) dans une série de dérivés trisubstitués du benzène
Authors: Nery H. , Canet D. , Azoui B. , Lalloz L. , Caubère P. 
Published: May 2005

AbstractLes déplacements chimiques du 13C, les couplages 13CH à une liaison, les couplages 13CH à trois liaisons (méta) ont été déterminés pour une série de dérivés trisubstitués du benzène, les substituants étant: Cl, NH2, N(C2H5)2, N(iC3H7)2, N(C2H4)2O. Les déplacements chimiques n'obéissent que médiocrement aux lois d'additivité habituelles. Des lois d'additivité relatives aux couplages mentionnés plus haut sont proposées. A de rares exceptions près, l'écart entre valeurs prévues et valeurs observées est inférieur à 10%.
Substituent effect of the nitro group on alkanes in carbon‐13 n.m.r. spectroscopy
Authors: Ejchart Andrezej 
Published: May 2005

AbstractLinear correlation coefficients were obtained for the substituent effect of the nitro group in primary nitroalkanes. The solvent effect of chloroform is also discussed, as well as the influence of the scalar relaxation on the half‐width of α‐carbons in13C n.m.r. spectroscopy.
Applications de la Résonance Dynamique du Proton et du Carbone‐13 à l'Etude d'Azines Hétérocycliques. Mécanismes de Formation et d'Isomérisation
Authors: Naulet M. , Leymarie‐Beljean M. , Martin G. J. 
Published: May 2005

AbstractCe travail présente une étude structurale par RMN 1H et 13C d'azines hétérocycliques, l'influence de l'isomerie Z/E sur les déplacements chimiques 13C est examinée. L'étude cinétique de la formation et de l'isomérisation Z/E de ces composés a été effectuée et les mécanismes de ces réactions sont discutés.
A theoretical interpretation of 13C screening data in unsaturated molecules
Authors: Jallali‐Heravi M. , Webb G. A. 
Published: May 2005

AbstractCarbon‐13 screening constants are calculated within the INDO/S level of approximation to Pople's model. Satisfactory agreement is obtained in most cases between the calculated and observed screening results. An analysis of the contributions of the π → σ*, σ → π* and σ → σ* transitions to the paramagnetic term shows that a linear relationship between 13C chemical shifts and the lowest energy transition is not present. The average excitation energies are found to vary appreciably among the molecules studied.
Carbon‐13 isotope effect on proton decoupled 13C and 31P n.m.r. spectra of bis(diphenylphosphino)acetylene
Authors: Paasonen R. , Enqvist J. , Karhu M. , Rahkamaa E. , Sundberg M. , Uggla R. 
Published: May 2005

AbstractHigh resolution proton decoupled 13C and 31P n.m.r. spectra of bis(diphenylphosphino)acetylene in (CD3)2SO and CDCl3 are analysed as ABX spectra to give the relative chemical shifts of the 13C and 31P nuclei as well as the spin–spin coupling constants 3J(PP) and nJ(PC). The differences in 31P shieldings are due to secondary 13C isotope effects which have been observed to be negligible over more than two bonds.
Assignment of the carbon‐13 chemical shifts of quinacrine, chloroquine and related compounds in D2O solution
Authors: Griggs Billy G. , Wilson W. David , Boykin David W. 
Published: May 2005

AbstractThe carbon resonances of quinacrine, chloroquine, acranil, 4‐aminopyridine and 9‐aminoacridine in D2O solution have been assigned. Resonance assignments were made using empirical shift parameters, partial proton decoupling, selective proton decoupling and by interpretation of the fully coupled spectra. The effect of pD on the carbon chemical shifts for quinacrine and chloroquine over the range of about 4.5 to 8.5 was observed. Characteristic chemical shifts for the aromatic ring carbons for deprotonation of the heteroaromatic nitrogen were observed.
How does the accuracy of NMR conformational analysis depend on the equilibrium constant?
Authors: Sergeyev N. M. 
Published: May 2005

AbstractAnalytical expressions are derived for the analysis of the accuracy of NMR determinations of conformational equilibrium constants, K. The relative error, σK/K, shows a nearly linear increase with K for two commonly used modifications of the NMR approach to conformational analysis (based on measurements of integral intensities and averaged chemical shifts).
Carbon‐13 nuclear magnetic resonance spectra. VIII—18α‐ and 18β‐glycyrrhetic acid derivatives
Authors: Duddeck Helmut , Elgamal M. H. A. , Ricca Guiliana Severini , Danieli Bruno , Palmisano Giovanni 
Published: May 2005

AbstractThe 13C NMR data of six pairs of 18α/18β‐glycyrrhetic acid derivatives are presented. It is shown that the configuration at C‐18 can easily be recognized by inspecting the chemical shifts of several characteristic carbons, e.g. C‐12, C‐13, C‐18 and C‐28. The shifts of these carbons originated by the change of the D/E ring junction proved to be largely independent of the substitution at C‐3 and C‐20.
On the stereochemistry of 1,4‐diheterocyclanes. IV—carbon‐13 NMR spectra and structural properties of 1,4‐dioxane‐2,3‐diols and their methyl‐substituted derivatives
Authors: Äyräs Pertti 
Published: May 2005

AbstractThe 1,4‐dioxane‐2,3‐diols and a number of their methyl‐substituted derivatives were synthesized and their 13C NMR spectra measured. The configurational properties were studied on the basis of the spectral data and chemical equilibration. For the parent compound the trans configuration is slightly more stable. The hydroxyl groups are predominantly axial. Introduction of a methyl group at the 2 position causes the cis configuration of the hydroxyl substituents to become more stable. The substituent effects on the chemical shifts were calculated and used to test the conformational homogeneity of the compounds. The results indicate a biased (chair) conformation for all the methyl‐substituted derivatives which were studied. Methyl groups have strongly predominating equatorial orientation in each case studied.
Effet de Solvant en RMN du Carbone‐13. III—Cas d'un Soluté Polaire: l'Acétone dans Divers Solvants et en Phase Gazeuse
Authors: Tiffon Bernard , Dubois Jacques‐Emile 
Published: May 2005

AbstractLe déplacement chimique des carbones de l'acétone a été déterminé en phase gazeuse et en fonction de la concentration dans dix‐neuf solvants dans le but de séparer les différents termes de constante d'écran dus aux interactions de l'acétone avec elle‐même (autoassociation) et avec les solvants. On montre que le terme de constante d'écran σw dǔ aux interactions de van der Waals (interprété à l'aide de l'expression théorique proposée par Rummens) est prépondérant pour les groupes méthyles par rapport au terme d'interactions spécifiques soluté–solvant σH. Par contre, le terme d'interactions spécifiques σH du carbone du carbonyle est huit fois plus grand que celui des groupes méthyles et il est prédominant lorsque des interactions dipole–dipole ou des liaisons hydrogène interviennent entre le soluté et le solvant. Aucune preuve formelle d'existence d'un terme de champ électrique proportionnel au champ de réaction d'Onsager n'a pu ětre établie, mais dans le cas des interactions dipole‐dipole, le terme σH est proportionnel au champ électrique du dipole d'une molécule de solvant couplé de façon antiparallèle avec le dipole du soluté. La variation du terme σH avec la dilution dans un solvant non associant est interprétée comme résultant du déplacement de l'équilibre d'autoassociation, dont la constante K est déterminée.
Downfield γ‐gauche and γ‐antiperiplanar effects on 13C NMR chemical shifts exerted by thiophene sulphur
Authors: de Haan J. W. , van Dommelen M. E. , van de Ven L. J. M. , Corvers A. 
Published: May 2005

AbstractThe γ‐effects of sulphur on 13C NMR chemical shifts have been measured in a series of steroidal compounds containing the thiophene ring in different configurations with respect to the rest of the molecule. The data constitute the first example of downfield effects exerted by sulphur on both gauche and antiperiplanar γ‐carbons. The γ‐gauche effect of sulphur amounts to 1.6–1.8 ppm, the γ‐antiperiplanar effect from practically zero to almost 1 ppm.
Structure elucidation with lanthanide‐induced shifts. 4—Bound shifts vs relative shifts
Authors: Raber Douglas J. , Johnston Milton D. , Campbell Catherine M. , Janks Christopher M. , Sutton Pamela 
Published: May 2005

AbstractThe use of lanthanide shift reagents (LSR's) to obtain additional structural information from nuclear magnetic resonance studies has gained widespread acceptance. However, there has not been general agreement with regard to the most appropriate methodology for analysis of the shifted NMR spectra. We present arguments that only the bound shifts (Δ1) corresponding to the LS complex should be used for correlation of lanthanide‐induced shifts with molecular structure by means of the pseudocontact equation. Several examples are discussed of compounds for which the relative induced shifts are dependent on the concentration of LSR. For such cases it is not possible for both Δ1 and Δ2 (the bound shift corresponding to the LS2 complex) to correlate successfully with the correct structure. Alternative methods of obtaining bound shifts are critically evaluated.
Spectres RMN des Polysaccharides et de leurs Dérivés: Influence des Substituants sur le Déplacement Chimique 13C
Authors: Gagnaire D. , Mancier D. , Vincendon M. 
Published: May 2005

AbstractL'influence des substituants méthyle et acétate sur le déplacement chimique 13C a été déterminée sur les polysaccharides liés par liaison glycosidique (α1→3), (α1→4), (β1→3) et (β1→4) suivants: pseudonigérane, β‐cyclodextrine, amylose, laminarane et cellulose. Nous avons utilisé les méthyl α et β glucopyranosides comme composés modès. La détermination de l'effet des substituants sur le déplacement chimique 13C nécessite l'attribution non ambiguë des spectres 13C des polysaccharides hydroxylés et substitués. On a utilisé pour cela la technique d'irradiation sélective hétéronucléaire et l'effet isotopique d'hydroxyle deutérié.
Carbon‐13 NMR. The analysis of the relaxation times T1 of benzofuran and of a series of its methyl derivatives. Correlations between molecular motions and structural properties
Authors: Platzer Nicole 
Published: May 2005

AbstractCarbon‐13 relaxation times (T1) and nuclear Overhauser enhancements (η) have been measured for benzofuran and a series of its methyl derivatives. The contributions of dipolar (T1 DD) and spin rotation (T1SR) mechanisms have both been determined. The temperature dependence of T1 has been studied. The relationships between molecular motions and structural properties have been emphasized. The overall motional anisotropy of the benzofuran molecule is increased by substitution in positions 2 and 5. The internal rotation of a methyl group may change depending on its position in the molecule and on the influence of other methyl groups in its close neighbourhood.
Determination of the configuration of substituted 1,4:3,6‐dianhydrohexitols by 13C NMR spectroscopy
Authors: Sohár P. , Medgyes G. , Kuszmann J. 
Published: May 2005

AbstractThe configurations of 1,4:3,6‐dianhydro‐2,5‐di‐O‐mesyl‐D‐mannitol, 1,4:3,6‐dianhydro‐2,5‐di‐O‐mesyl‐D‐glucitol, 1,4:3,6‐dianhydro‐2,5‐di‐O‐mesyl‐L‐iditol, 1,4:3:6‐dianhtydro‐2‐deoxy‐2‐iodo‐5‐O‐mesyl‐D‐mannitol, 1,4:3:6‐dianhtydro‐2‐deoxy‐2‐iodo‐5‐O‐mesyl‐D‐glucitol, 1,4:3,6‐dianhydro‐2‐deoxy‐2‐iodo‐5‐O‐mesyl‐L‐iditol, 1,4:3,6‐dianhydro‐2,5‐dideoxy‐2,5‐diiodo‐D‐glucitol and 1,4:3,6‐dianhydro‐2,5‐dideoxy‐2,5‐diiodo‐L‐iditol were determined by 13C NMR spectroscopy, by invoking the field‐effect.
Nitrogen nuclear magnetic resonance spectroscopy. Nitrogen‐15 and proton chemical shifts of methylanilines and methylanilinium ions
Authors: Psota Linda , Franzen‐Sieveking Marcia , Turnier Jocelyne , Lichter Robert L. 
Published: May 2005

AbstractNitrogen and carbon electron densities of the toluidines and xylidines have been recalculated by the INDO method; previously published errors have been corrected. Although the nitrogen‐15 chemical shifts of these compounds still display the earlier suggested correlation with σ and total electron densities, the calculated inverse correlation with proton electron densities has been shown to be incorrect. Methyl proton chemical shifts of these compounds display no meaningful correlation with the nitrogen shifts. The nitrogen chemical shifts of the toluidinium and xylidinium ions correlate moderately well with the 13C chemical shifts of the analogous di‐ and tri‐methylbenzenes.
Etude par RMN du Proton de la Stéréochimie de Composés Ethyléniques Trisubstitués. Calcul Empirique et Calcul par Incréments de la Constante d'Ecran
Authors: Brémond M. , Martin G. J. , Cariou M. 
Published: May 2005

AbstractNous avons appliqué les approximations de Pascual et de Tobey pour évaluer le déplacement chimique d'un proton éthylénique dans le cas de substituants qui causent souvent des difficultés d'attribution de signaux. Les résultats des calculs empiriques de la différence d'écran entre les protons éthyléniques des deux configurations Z et E sont comparés aux valeurs expérimentales des déplacements chimiques dans une série d'aryl‐2 propène nitriles. La configuration Z s'avère correspondre au proton le moins blindé et les effets de solvants observés concordent avec cette attribution. Lorsque la configuration Z est prépondérante, sa nature est établie sans ambiguïté, car de très faibles quantités de l'autre isomère E ont pu ětre obtenues et étudiées. Les résultats de cette méthode sont satisfaisants et permettent de déterminer de nouveaux paramètres d'incréments additifs (NH2, OH, ONa).
13C‐NMR‐Spektren von Tetracyclo[4.1.0.02,4.03,5]heptanen, Tetracyclo[5.1.0.02,4.03,5]octanen und Tricyclo[4.1.0.02,7]hept‐3‐enen. Ungewöhnliche δ‐ und γ‐Substituenteneffekte
Authors: Christl Manfred , Buchner Wolfgang 
Published: May 2005

Abstract13C‐NMR‐spektroskopische Daten von elf Tetracyclo[4.1.0.02,4.03.5]heptanen, zwei Tetracyclo‐[5.1.0.02,4.03,5]octanen und zwölf Tricyclo[4.1.0.02,7]hept‐3‐enen werden mitgeteilt. In den Tetracycloheptanen üben 7‐ständige Halogene große δ‐Substituenteneffekte aus, die im endo‐Fall das C‐4‐Signal um ca. 6 ppm nach tieferem Feld rücken und im exo‐Fall am C‐3‐Signal von der Natur des Halogens abhängige Hochfeldverschiebungen hervorrufen, wobei Fluor mit 9,1 ppm das Maximum erreicht. Ein Orbitalmodell zur Deutung der Hochfeld‐δ‐Effekte wird vorgeschlagen. Die fluorhaltigen Verbindungen enthüllen einen Zusammenhang zwischen den Substituenteneffekten und den zugehörigen 13C19F‐Kopplungskonstanten. 5‐Substituenten in Tricycloheptenen sind γ‐Substituenten von C‐1, C‐3 und C‐7 und verschieben die Absorptionen dieser Kerne nach tieferem Feld. Die Substituentenabhängigkeit der Effekte folgt etwa jener in 1‐substituierten Adamantanen, ihre Gröβe übersteigt aber im Fall von C‐7 die Adamantanwerte um ein Mehrfaches, wobei sich Brom mit 15,5 ppm als Spitzenreiter profiliert.
A contradistinction in the magnetic (13C NMR spectroscopy) and chemical behaviour of 4‐Oxo‐4,5,6,7‐tetrahydroindole derivatives
Authors: Ramadas S. R. , Padmanabhan S. 
Published: May 2005

AbstractCarbon‐13 NMR data are reported for a series of 1,2‐diaryl‐4‐oxo‐4,5,6,7‐tetrahydroindoles, 6‐methyl‐2‐phenyl‐4‐oxo‐4,5,6,7‐tetrahydrobenzofuran and 1‐,6‐dithiaindan‐4‐one. The chemical shifts δ 193–196, δ 195.5 and δ 184 are identified for the carbonyl carbon (C‐4) in the tetrahydroindoles, tetrahydrobenzofuran and dithiaindan derivatives, respectively. These shifts are located in the same region as that reported for the corresponding carbonyl carbon in aryl conjugated ketones. An excellent correlation between the chemical shift for the carbonyl carbon and the chemical reactivity of the ketonic function is noticed in the case of the latter two series of ketones while such a correlation is typically absent in the case of the 4‐ketotetrahydroindole derivatives.
Carbon‐13 magnetic resonance spectra of aldosterone, 18‐hydroxydeoxycorticosterone and 18‐hydroxyprogesterone
Authors: Genard P. 
Published: May 2005

AbstractThe 13C NMR spectra of aldosterone in various solvents show the presence of only the tautomeric forms with hemi‐acetal (11–18) and hemi‐ketal (18–20) bridges. Solutions of 18‐hydroxy‐11‐deoxycorticosterone (6) and of 18‐hydroxyprogesterone in CDCl3 contain mainly the hemi‐ketal (18–20) tautomer. Solutions of 6 in more polar solvents also contain—although to a lesser extent—a second form which may be a dimer or, more probably, a form representing two retamers with appreciable populations at the 21‐CH2OH group.
Spectroscopie RMN du Carbone‐13 de Thiocétones Aliphatiques: Propanethione et Dérivés, Thiocétones Bicycliques et α Cyclopropaniques
Authors: Andrieu Claude G. , Debruyne Danièle , Paquer Daniel 
Published: May 2005

AbstractLes spectres de RMN du carbone‐13 de diverses cétones et thiocétones aliphatiques ont été déterminés et expliqués. Le groupe thiocarbonyle est plus sensible à l'effet inducteur des groupes alkyles voisins que le groupe carbonyle. II n'existe pas de relation directe avec la transition π*←n. L'effet mésomère est plus grand dans le groupe cyclopropylthiocarbonyle que dans le groupe cyclopropanoyle. L'influence du thiocarbonyle sur les atomes voisins est plus importante que celle du carbonyle.