E. V. Bryukhova

35CL NQR SPECTRA, STRUCTURE, AND MUTUAL INFLUENCE OF SUBSTITUENTS IN THE SERIES OF CHLORINE-CONTAINING ORGANIC COMPOUNDS OF PENTAVALENT PHOSPHORUS

Regularities of transmission of the effect of equatorial and axial substituents were established for a number of chlorine-containing organic compounds of pentatalent phosphorus using35Cl NQR spectra. The field constants of35Cl NQR frequencies of the chlorine atoms participating in the P−Cl bond were estimated for a series of tetrahedral phosphorus ions. The35Cl NQR frequencies of chlorine atoms in tetracoordinated ions of pentavalent phosphorus and in analogous isoelectronic silicon compounds are related by a linear dependence.

Nuclear quadrupole resonance spectra on55Mn,75as,121Sb, and123Sb atoms of C5H5Mn(CO)2-ligand complexes

1. A study was made of the NQR spectra on the55Mn,121Sb,123Sb, and75As atoms of some C5H5Mn(CO)2-ligand complexes. 2. The replacement of one carbonyl group leads to a sharp increase in the asymmetry parameter and a slight change in the constant of the quadrupole bond on the Mn atom. 3. A decrease in the quadrupole constant on the As and Sb atoms in the complex, with a retention of the value of the asymmetry parameter when compared with the free As(C6H5)3 and Sb(C6H5)3, indicates that the complex formation occurs via the free electron pair of the Sb and As atoms.

On determination of the strength of local electric fields at the bromine atoms in the series of compounds BrCH2R by79Br NQR spectroscopy

The values of changes in the strength of local electric fields at the bromine atoms for a series of compounds BrCH2R were determined from a hyperbolic equation relating the79Br NQR frequencies to their field constants. The totalities of electron-acceptor and electrodonor substituents R are described by equations of the same type differing in their parameters.

127I and79Br NQR spectra of halo-substituted phenols and phenylmercury phenoxides

The full127I NQR spectra of a series of iodo-substituted phenols and phenylmercury phenoxides have been studied. The quadrupole coupling constants and asymmetry parameters have been determined. The character of the OH...Hal hydrogen bond has been found to depend on the nature of substituents in the ring. Correlation dependences of the asymmetry parameters on the sum of the substituents resonance constants have been found for both coordinated as well as for non-coordinated iodine atoms.

Field constants of79Br and127I NQR of halogen derivatives of carbon

ConclusionsA study has been made of the NQR frequency field constants for the chlorine, bromine, and iodine atoms. It has been shown that the degree to which the field constants are characteristic decreases in the series Cl-Br-I.

127I NQR spectra in series of iodo derivatives of aliphatic compounds

ConclusionsWe were the first to study the complete NQR spectra of iodine for a number of haloaliphatic compounds. An additive scheme for calculating the NQR frequencies in the HnCl4−n series was constructed. The values of the asymmetry parameters in the studied compounds were analyzed.

79Br and127I nqr spectra in series of acetylene derivatives

ConclusionsThe complete79Br and127I NQR spectra of a number of bromo and iodo derivatives of acetylene were studied for the first time, and the field constants of the NQR frequencies were determined. It was found that the asymmetry parameters in them are low. Changes in the field constants are determined by the competing conjugation of the iodine atom and the corresponding substituents.

35Cl,79Br, and127I NQR spectra of several polyhalophenols and their phenylmercury derivatives

Conclusions1.The intramolecular contribution to the splitting of the NQR frequencies in the 2,6-dihalo-4-X-derivatives of phenol has been separated out. The strength of the intramolecular hydrogen bond is substantially dependent on the nature of the substituants in position 4. The splittings in the NQR spectra are reduced upon passing from electron-accepting substituents to electron-donating substituents.2.The intramolecular coordination interactions of mercury atoms with halogen atoms leads to a reduction and splitting of the NQR frequencies of the halogen atoms in positions 2 and 6 and they are only slightly dependent on the substituent in position 4.

Determination of the strength of the intramolecular electric field of the NO2 group by the NQR method

ConclusionsComparison of the investigated NQR spectra of the halogen atoms in a series of methane nitro derivatives with the field constants of the halogen atoms makes it possible to estimate the averaged intramolecular electric field created by the NO2 group.

35Cl and79Br NQR spectra of dicyclopentadienyl-tungsten and molybdenum dihalides

ConclusionsThe NQR frequencies of the studied Cp2WHal2 are nearly twice the frequencies of the analogous titanium derivatives, which can be due to a much smaller involvement of the pπ electrons of the halogen atom in forming the W-Hal bond when compared with Ti-Hal.