Yu. N. Sheinker

Correlation of the chemical shifts with π-electron densities in mono-derivatives of benzene, pyridine, and pyrazine

1. n nIn the series of functional mono-derivatives of benzene, pyridine, and pyrazine, we found an approximate linear correlation between the changes in the chemical shifts of the protons of the ring, situated in the ortho- and para-positions relative to the substituent, and the changes in the π-electronic charges on the adjoining carbon atoms. n n n n n2. n nA substantial influence upon the shielding of the meta-protons is exerted by the effect of the electrical field of π-charges localized on the atoms of the ring next to the meta-carbon atom. n n n n n3. n nThe correlation found for the chemical shifts of the para-protons and the chemical shifts of the meta-protons corrected for the effect of the electric field, within the corresponding series of derivatives of six-membered aromatic rings, is an important experimental substantiation of the correctness of the selection of heteroparameters for performing the calculations according to the Huckel molecular orbital method.

Integral intensities of the carbonyl bands in the IR spectra of heteroannularly substituted esters of ferrocenecarboxylic acid

1. n nThe integral intensities of the carbonyl bands in the IR spectra of 13 heteroannularly substituted esters of ferrocenecarboxylic acid have been measured. n n n n n2. n nThe transannular influence of substituents is approximately half that of the same groups in the para position of a phenyl nucleus. At the same time, the +C effect of electron-donating substituents in the esters investigated is smaller than in the analogous benzene derivatives.

Some tetrazolo-[1,5-b]- and s-Triazolo-[4,3-b]-pyridazines and their IR spectral characteristics

1. n nA series of tetrazolo-[1,5-b]- and s-triazolo-[4,3-b]-pyridazines, containing cycloalkylamine and azide groups in the 6-position, were synthesized. A chemical characterization of them is given. n n n n n2. n n6-N-cycloalkylaminotetrazolo-[1,5-b]-pyridazines possess a tetrazole structure, while the weak absorption bands present in their spectra at 2100–2200 cm−1 are overtones or compound tones of the basic valence vibrations of the rings. n n n n n3. n nThe strong splitting of the azide bands in the spectra of 6-azidotetrazolo-[1,5-b]- and 6-azido-s-triazolo-[4,3-b]-pyridazines confirms the idea that the cause of the splitting of the azide bands in the spectra of a number of organic azides is Fermi resonance.

The infrared spectra of aroylmethylene triphenylphosphoranes and their salts

1. n nWe have measured the integral intensities of carbonyl absorption in aroylmethylene triphenylphosphoranes and their salts. The observed facts are discussed from the point of view of electron donor and electron acceptorproperties of the phosphorus atom and the aromatic nuclei of the aroyl groups. n n n n n2. n nWe have suggested a relationship for the absorption bands in the region 1317–1390 cm−1 for aryl and 1389–1412 cm−1 for aroylmethylene triphenylphosphoranes to oscillation of the P=C bond.

Frequencies and intensities of the infrared absorption bands of the valence and deformed vibrations of the NH2 group in primary amines

1. n nThe question of the characteristic nature of the valence and deformational vibrations of the NH2 group was considered on the basis of the solution of the vibrational problem of the methylamine molecule. n n n n n2. n nThe force and electrooptical parameters of the NH2 group in various compounds were calculated according to the experimental values of the frequencies and intensities of the bands of the valence vibrations of the amino group, considering their characteristic features with respect to frequency and shape. n n n n n3. n nA linear relationship between the values of the electrooptical and force parameters, on the one hand, and the basicity of the amines, on the other, was found in the series of substituted anilines. n n n n n4. n nThe intensities of the bands of the valence vibrations of the NH2 group are more sensitive to the influence of the solvent than the intensities of the deformational vibrations of the amino group.

Integral intensities of the carbonyl bands of a number of pyrones and quinones

1. n nThe integral intensities of the carbonyl bands of a number of pyrones and quinones were measured. n n n n n2. n nThe observed increase in the integral intensities of the carbonyl bands in certain classes of compounds and the decrease in other classes are explained by the tendency to form an aromatic system, producing an increase or decrease in the electron density on the carbonyl oxygen. n n n n n3. n nThe high values of the intensities of pyrones can be used for structural-analytical purposes to distinguish pyrones, especially of natural origin, from the corresponding lactones, esters, and ketones.

Integral intensity of C=O peaks in the IR-spectra of substituted α-pyrones

1. n nThe integral absorption intensity of carbonyl peaks in the IR spectra of 17 substituted α-pyrones was measured. n n n n n2. n nThe effect of substituents in the 3-position was due mainly to electrostatic interactions (polar effects), but in the 5- and 6-positions to conjugative effects, Substituents in the 5-position had a greater influence on the C=O group than those in the 6-position.

Infrared spectra of acylmethylenetriphenylphosphoranes and their salts

1. n nIn the infrared spectra of a number of acylmethylenetriphenylphosphoranes, the bands of the carbonyl groups are displaced in the low-frequency direction, while in the spectra of phosphonium salts, these bands occupy a normal position. n n n n n2. n nThe intensities of the carbonyl bands in the spectra of acylmethylenetriphenylphosphoranes are considerably increased, while in the spectra of the salts they are somewhat reduced in comparison with the normal values. n n n n n3. n nThe data obtained agree with the ylide structure of acylmethylenetriphenylphosphoranes, in which the polarity of the C=O groups is greatly increased, and the negative charge is localized to a considerable degree on the oxygen, rather than on the ylide carbon as in alkylidenephosphoranes.

Integral intensity of the deformation vibration band of the amino group in the IR-spectra of substituted anilines

1. n nThe integral intensities A of theδ NH2 band in the IR spectra of a series of substituted anilines has been studied and it has been shown that the values obtained are in rather satisfactory linear relationship to the Hammet σ-constants. n n n n n2. n nThe deviations from a linear relationship of A to σ, which are observed for some of the compounds investigated, have been considered.

Integral intensities of IR bands characteristic of the vibrations of the functional groups in derivatives of ferrocene

1. n nThe frequencies of the IR bands of the valence vibrations of electron-acceptor functional groups in mono -substituted derivatives of ferrocene are lowered and the integral intensities are noticeably increased in comparison with the corresponding derivatives of benzene. n n n n n2. n nThe integral intensities of the carbonyl bands in the derivatives of ferrocene that are disubstituted in different rings are lowered as a result of transmittal of the mutual influence of the substituents through the ferrocene nucleus.