Ye. N. Guryanova

Bio: Ye. N. Guryanova is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 11 citations.

Frequency shift in the NQR spectra of charge transfer complexes

Abstract: In the framework of Mulliken's theory a frequency shift in NQR spectra has been considered. It has been shown that in MO LCAO approximation the frequency shift is proportional to the degree of the charge transfer. For the picrylchloride complexes the linearity of this dependence has been confirmed. It has been shown experimentally that the shift is appreciably affected by steric interactions.

Degree of Charge Transfer in Donor–Acceptor Systems of the π–π Type

Abstract: The principal methods for the determination of the degree of charge transfer are examined and experimental data on the intermolecular distribution of electron density in charge-transfer complexes and radical-ion salts of the π–π are surveyed. The relation between the degree of charge transfer and the ionisation potential of the donor, the half-wave potential in the anodic oxidation of the donor, and the electron affinity and the polarographic reduction potential of the acceptor, which largely determine the degree of charge transfer in donor–acceptor systems of the π–π type, is discussed. The bibliography includes 104 references.

Spectroscopy of electron donor-acceptor systems

Abstract: The formation of complexes between electron donors and acceptors has long been recognized a s an important phenomenon. Many of themolecular complexes are colored and give rise to new absorption bands in the electronic spectra. These molecular complexes have been investigated by employing a variety of physical methods such as optical spectroscopy, magnetic resonance spectroscopy, calorimetry, dielectric measurements, and X-ray diffraction. Studies of donor-acceptor complexes are of value in understanding various types of reaction mechanisms, including molecular phenomena in biological systems. Some of the relatively recent developments in the study of molecular complexes are: the classification of donors and acceptors by Mulliken [l], vibrational spectroscopy, particularly in the very-low-frequency region [2,3], estimation of the per cent charge transfer by dipole moment measurements [4–6], studies of weak interactions (contact pairs) [7], spectra and thermodynamics of complexes in vapor phase [8,...

Weak Halogen Bonding in Solid Haloanilinium Halides Probed Directly via Chlorine-35, Bromine-81, and Iodine-127 NMR Spectroscopy

Abstract: A series of monohaloanilinium halides exhibiting weak halogen bonding (XB) has been prepared and characterized by 35Cl, 81Br, and 127I solid-state nuclear magnetic resonance (SSNMR) spectroscopy in magnetic fields of up to 21.1 T. The quadrupolar and chemical shift (CS) tensor parameters for halide ions (Cl–, Br–, I–) which act as electron density donors in the halogen bonds of these compounds are measured to provide insight into the possible relationship between halogen bonding and NMR observables. The NMR data for certain series of related compounds are strongly indicative of when such compounds pack in the same space group, thus providing practical structural information. Careful interpretation of the NMR data in the context of novel and previously available X-ray crystallographic data, and new gauge-including projector-augmented-wave density functional theory (GIPAW DFT) calculations has revealed several notable trends. When a series of related compounds pack in the same space group, it has been possi...

Crystal field effects in nuclear quadrupole resonance

Abstract: A quantitative investigation of the crystal field effect is quite difficult. From the large number of NQR measurements available, the following qualitative conclusions can be drawn. a) The crystal field effect is of the order of δv (35Cl) = ±500 kHz in Cl atoms bound to carbon. b) With increasing ionic character of a bond Cl-X, the crystal field effects become more pronounced, because the multipole moments of the molecules in the lattice and the quadrupole polarizability of the core electrons of the 35Cl nucleus increase. This second point is equivalent to an increasing antishielding factor γ∞ for Cl. c) Quantitative calculations of the charge transfer in molecular compounds or of the ionic character induced within a molecule through the formation of the complex are only possible if the crystal structure is known and single-crystal NQR data (including η) are available. From NQR powder data, only qualitative conclusions can be drawn. d) The temperature dependence of NQR frequencies should be investigated carefully to correct for the crystal field effect as accurately as possible. e) For other nuclei besides 35Cl, and 79,81Br, such as 127I, 14N,..., more experimental evidence is needed to clarify the connection between NQR and the specific interactions between molecules in the solid state and in molecular addition compounds.

Nuclear Quadrupole Resonance in Studies on Molecular Compounds

Abstract: The review describes and gives a systematic account of data on the application of the nuclear quadrupole resonance method in studies on donor–acceptor complexes. Particular attention is paid to factors responsible for the changes in the principal parameters of nuclear quadrupole resonance spectra. The bibliography includes 87 references.