Attenuation of the Substituent Effects Along the Aliphatic Chain

2004 ◽  
Vol 69 (5) ◽  
pp. 984-995 ◽  
Author(s):  
Stanislav Böhm ◽  
Otto Exner
Keyword(s):  
Functional Group ◽  
Inductive Effect ◽  
Substituent Effects ◽  
Transmission Factor ◽  
Isodesmic Reaction ◽  
Aliphatic Chain ◽  
Model Compounds ◽  
Derivatives Of ◽  
Methylene Group ◽  
Isolated Molecules

Two series of model compounds were devised to follow the attenuation of substituent effects with an interposed methylene group: short-chain aliphatic compounds 1 and derivatives of bicyclo[2.2.2]octane 5. In all compounds, chlorine atom acts as substituent and charged oxygen atom as the functional group; the interaction of both is measured by the reaction energy of the isodesmic reaction calculated at the B3LYP/AUG-cc-pVTZ//B3LYP/6-311+G(d,p) and/or B3LYP/6-311+G(d,p) levels. Attenuation of the substituent inductive effect with the distance is less steep than observed previously in solution. It depends also markedly on the conformation but cannot be reproduced, not even approximately, by the electrostatic formula. Only for simple regular conformations, it can be described approximately by an exponential function with the transmission factor for one methylene group equal to 0.74. The behavior of isolated molecules differs in this case distinctly from the reactivity in solution. Nevertheless, the significance of the two formulas, electrostatic and exponential, is similar in the isolated molecules and in solution. These formulas represent only two different, rather crude mathematical approximations and cannot be given any physical meaning.

Functional group and substituent effects, both steric and electronic, upon the ultraviolet absorption spectra of some N-alkyl- and N,N-dialkyl-derivatives of some cinnamamides and benzalcyanoacetamides

1969 ◽  
Vol 47 (17) ◽  
pp. 3278-3280 ◽  
Author(s):  
A. D. Delaney ◽  
D. J. Currie ◽  
H. L. Holmes
Keyword(s):  
Hydrogen Atom ◽  
Absorption Spectra ◽  
Functional Group ◽  
Substituent Effects ◽  
Ultraviolet Absorption ◽  
Long Wavelength ◽  
Wavelength Absorption ◽  
Derivatives Of

Conjugative and steric constants for N-substituted carboxyamide groups have been derived which allow the calculation of the long wavelength absorption maxima of N-alkyl- and N,N-dialkyl-derivatives of cinnamamide and benzalcyanoacetamide. Deviations between calculated and observed values indicate that there may be steric interference between bulky N,N-dialkylcarboxyamide groups and the benzylic hydrogen atom.

The Carbon-13 Nuclear Magnetic Resonance Spectra of 2-Acetamido-2-deoxy-D-hexoses and some Specifically Deuteriated, O-Acetylated, and Phosphorylated Derivatives

1973 ◽  
Vol 51 (22) ◽  
pp. 3812-3819 ◽  
Author(s):  
D. R. Bundle ◽  
H. J. Jennings ◽  
Ian C. P. Smith
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Substituent Effects ◽  
Model Compounds ◽  
Initial Assignment ◽  
Nuclear Magnetic Resonance Spectra ◽  
Polysaccharide Antigens ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13C n.m.r. spectra of the 2-acetamido-2-deoxy-D-hexoses and some 3-O-acetyl and 1-phosphate derivatives are assigned and discussed. To facilitate the interpretation of the spectra, an initial assignment of the resonances in the spectrum of 2-acetamido-2-deoxy-D-glucose was required. For this purpose, both the 3-2H and 4-2H derivatives of this acetamido-hexose were synthesized. These syntheses are reported together with those of 2-acetamido-3-O-acetyl-2-deoxy-D-glucose and 2-acetamido-2-deoxy α- and β-D-glucose-1-phosphate. These model compounds were used to study substituent effects related to the 2-acetamido-2-deoxy-D-hexose-containing polysaccharide antigens of N. meningitides.

Substituent effects on the electronic structure of the flat Blatter radical: Correlation analysis of experimental and computational data

2021 ◽  
Author(s):  
Piotr Kaszynski ◽  
Paulina Bartos ◽  
Aniket A. Hande ◽  
Anna Pietrzak ◽  
Anna CHROSTOWSKA
Keyword(s):  
Electronic Structure ◽  
Correlation Analysis ◽  
Functional Group ◽  
Substituent Effects ◽  
Cyclization Reactions ◽  
Computational Data ◽  
Derivatives Of

A series of C(10)–substituted derivatives of the 2-Ph-3H-[1,2,4]triazino[5,6,1-kl]phenoxazin-3-yl was obtained using the aza-Pschorr, photochemical and radical–induced cyclization reactions, and through functional group transformations of the C(10)–amino and C(10)–iodo derivatives. The...

Functional-group and substituent effects, both steric and electronic, upon the ultraviolet absorption spectra of some conjugated heteroenoid compounds

1967 ◽  
Vol 45 (13) ◽  
pp. 1567-1580 ◽  
Author(s):  
D. J. Currie ◽  
C. E. Lough ◽  
R. F. Silver ◽  
H. L. Holmes
Keyword(s):  
Functional Group ◽  
Inductive Effect ◽  
Substituent Effects ◽  
Wavelength Region ◽  
Steric Effects ◽  
Electronic Effects ◽  
Amino Groups ◽  
Empirical Parameter ◽  
Long Wavelength ◽  
Constant E

The positions of the long-wavelength maxima in the spectra of some 300 compounds of generalized formula I may be accommodated by assuming that the observed maximum is equal to that of styrene + Δλ (the conjugative effect of A) + Δλ′ (the inductive effect of B) + ΣΔλ″ (the sum of the steric effects of the A, B, and phenyl groups) + D (an empirical parameter related to X and Y). These arguments have been extended to the spectra of II. Δλ′ is related to the σ value for meta-substituted benzene derivatives or to σ*. D for meta- and [Formula: see text]para-substituted derivatives roughly correlates with the appropriate σ+ values, whereas D for ortho-substituted derivatives is related to a simple function involving the D value for para substitution and the steric substituent constant, ES. For compounds of generalized formula III, the electronic effects of the A and B groups cancel but the steric effects are additive.Multiple bands occur in the long-wavelength region of the spectra for compounds containing halogen, alkoxy, or amino groups. These groups are highly polarizable and are considered to function both as electron donors and electron sinks.

Revision of the Dual-Substituent-Parameter Treatment; Reaction Series with a Donor Reaction Centre

2007 ◽  
Vol 72 (8) ◽  
pp. 1158-1176 ◽  
Author(s):  
Stanislav Böhm ◽  
Otto Exner
Keyword(s):  
Substituent Effects ◽  
Protonated Form ◽  
Isodesmic Reaction ◽  
Reaction Centre ◽  
Reaction Series ◽  
Substituted Phenols ◽  
Substituted Anilines ◽  
The Common ◽  
Substituted Benzoic Acids ◽  
Isolated Molecules

The dual-substituent-parameter (DSP) treatment was challenged previously as not generally valid. Just in the fundamental reaction, dissociation of 4-substituted benzoic acids and in similar reactions, DPS does not hold for acceptor substituents because the constant reaction centre is itself an acceptor. In this communication, the reverse case was examined, i.e., a reaction series with a donor reaction centre: basicity and acidity of 4-substituted anilines, and acidity of 4-substituted phenols. The reaction energies were calculated for 19 common substituents at the level B3LYP/6-311+G(d,p)//B3LYP/6-311+G(d,p); the substituents effects were also estimated separately in uncharged molecules and in the ions in terms of isodesmic reaction. DSP is valid and its resonance term is highly significant for molecules with acceptor substituents; donor substituents behave differently and cannot be described by simple resonance constants. Basicity of substituted anilines is more complex since the substituent effects are quite different in the free base and in the protonated form: basicity is controlled by a combination of various effects. It is recommended to use DSP only for acceptor substituents with a donor reaction centre or vice versa; otherwise the accuracy is decreased. All results were obtained with isolated molecules and with resonance constants derived on isolated molecules; however, they retain their validity even with the common constants σR determined from the reactions in solution.

Toxicity of Para-Chloro Substituted Benzene Derivatives in the Microtox™ Test

1985 ◽  
Vol 20 (2) ◽  
pp. 36-43 ◽  
Author(s):  
Klaus L.E. Kaiser ◽  
Juan M. Ribo ◽  
Brian M. Zaruk
Keyword(s):  
General Formula ◽  
Functional Group ◽  
Structural Parameters ◽  
Systematic Investigation ◽  
Photobacterium Phosphoreum ◽  
Benzene Derivatives ◽  
Quantitative Structure ◽  
Chlorinated Benzenes ◽  
Chloro Derivatives ◽  
Derivatives Of

Abstract This paper gives the results of part of a systematic investigation into contaminant toxicity to Photobacterium phosphoreum in the Microtox™ test. Reported are the toxicity values for 39 para-chloro substituted benzene derivatives of the general formula l-Cl-C6h4-4-X=CH2CH(NH2)COOH, F, SO2NH2, OCH2COOH, CH2COOH, CONHNH2, NHCOCH3, CONH2, CH=CHCOOH, SeOOH, CH2NH2, CH2CH2NH2, NO2, H, CF3, CHO, CH2OH, OH, CH3, CCl3, COCH3, COOH, NH2, SO2C6H5, Cl, CH2COCH3, COCl, CN, OCH3, NCO, NHCH3, I, COC6H5, CH2Cl, SH, CH2SH, NCS, CH2CN and SO2C6H4Cl. Except for the last compound, whose solubility is below the required concentration, the toxicities increase in the presented order with a total range of more than three orders of magnitude. The data are discussed in terms of quantitative structure-toxicity correlations with compound-specific structural parameters. In combination with a previously developed submodel on chlorinated benzenes, phenols, nitrobenzenes and anilines, the observed relationships allow the prediction of the toxicity of some 780 possible chloro derivatives of the general formula C6H5-nClnX, where n=<5 and X is a functional group as listed above.

Inductive effect in EI-mass spectra of some 5,6-dihalogenides and 5,6-halohydrins of 5α-cholestan-3β-ol and 3β-acetoxy-5α-cholestane

1982 ◽  
Vol 47 (11) ◽  
pp. 2946-2960 ◽  
Author(s):  
Antonín Trka ◽  
Alexander Kasal
Keyword(s):  
Mass Spectra ◽  
Inductive Effect ◽  
Molecular Ions ◽  
Hydroxyl Group ◽  
Halogen Atoms ◽  
Derivatives Of

Partial EI-mass spectra of 3β-hydroxy- and 3β-acetoxy-5α-cholestanes substituted in positions 5α-, 6β- or 5α,6β- with a hydroxyl group or halogen atoms (fluorine, chlorine, bromine) are presented. The molecular ions of 5α,6β-disubstituted derivatives of 3β-hydroxy-5α-cholestane (or of its 3-acetate) are considerably more stable than the corresponding monosubstituted derivatives if at least one of the pair of the vicinal substituents is chlorine or fluorine. This increase in stability, most striking in 5α- and 6β-fluoro compounds, is explained by the inductive effect.

Infrared spectra and substituent effects in 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones

1983 ◽  
Vol 48 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Alexander Perjéssy ◽  
Pavol Hrnčiar ◽  
Ján Šraga
Keyword(s):  
Substituent Effects ◽  
Phenyl Group ◽  
Wave Number ◽  
Vibrational Coupling ◽  
Wave Numbers ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The Relationship ◽  
Derivatives Of ◽  
Effect Of Structure

The wave numbers of the fundamental C=O and C=C stretching vibrations, as well as that of the first overtone of C=O stretching vibration of 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones and 1,3-cycloheptanedione were measured in tetrachloromethane and chloroform. The spectral data were correlated with σ+ constants of substituents attached to phenyl group and with wave number shifts of the C=O stretching vibration of substituted acetophenones. The slope of the linear dependence ν vs ν+ of the C=C stretching vibration of the ethylenic group was found to be more than two times higher than that of the analogous correlation of the C=O stretching vibration. Positive values of anharmonicity for asymmetric C=O stretching vibration can be considered as an evidence of the vibrational coupling in a cyclic 1,3-dicarbonyl system similarly, as with derivatives of 1,3-indanedione. The relationship between the wave numbers of the symmetric and asymmetric C=O stretching vibrations indicates that the effect of structure upon both vibrations is symmetric. The vibrational coupling in 1,3-cycloheptanediones and the application of Seth-Paul-Van-Duyse equation is discussed in relation to analogous results obtained for other cyclic 1,3-dicarbonyl compounds.

Chemometric Analysis of Substituent Effects. VII. Inductive Effect as a Basic Substituent Effect. Isoeffect Substituent Constant

1995 ◽  
Vol 60 (8) ◽  
pp. 1316-1332 ◽  
Author(s):  
Oldřich Pytela ◽  
Aleš Halama
Keyword(s):  
Inductive Effect ◽  
Chemical Shifts ◽  
Quantitative Description ◽  
Substituent Effects ◽  
Intersection Point ◽  
Chemometric Analysis ◽  
Reaction Centre ◽  
Substituent Constant ◽  
Modified Method ◽  
Substituted Benzoic Acids

The paper deals with chemometric analysis of the inductive effect. The notion of inductive effect is discussed, and unambiguous definitions are given for the notions of triad: reaction centre-basic skeleton-substituent, and the therewith connected definitions of inductive effect. For a quantitative description of inductive effect 7 types of chemical models were selected including noncyclic compounds, cyclic, and bicyclic compounds, derivatives of quinuclidine, 3-substituted benzoic acids, sulfonamides and pyridines. Altogether 139 sets of experimental data from literature have been used including altogether 1 294 points (9.3 points per set, 5 points at least) reflecting substituent effects of 34 substituents. It has been found that for a standard model the dissociation of substituted bicycloalkanecarboxylic acids only is satisfactory, all the other models reflecting also the mesomeric effects to variable extent (up to 10%). A distinctly different substitution behaviour was observed with 19F and 13C NMR chemical shifts of 4-substituted 1-fluoro- or 1-methylbicyclo[2.2.2]octanes. The earlier suggested model of substituent effects based on different way of transmission of substituent effects (3 classes) has been used for separating the inductive and mesomeric effects: it is mathematically presented as a set of straight lines with the intersection point at the so-called isoeffect substituent constant. Using the modified method of conjugated deviations a chemometric scale has been created for the inductive effect which agrees very well with the conventional scales given in literature; the only differences were observed for F and CH=O substituents (which are overestimated and underestimated, respectively, in literature). In the context given the inductive effect appears as a fundamental quantity forming a basis for quantitative description of other effects transferred by electrons.

Sign in / Sign up

Export Citation Format

Share Document