[en] The stochastic theory of Moessbauer line shapes is formulated in a fashion which allows the evaluation of the spectral shapes for absorbers of arbitrary thickness, texture, and an anisotropic Lamb-Moessbauer factor. The results are specialized to a two-state-relaxation model of fluctuating electric hyperfine interaction in the case of an absorber of axially symmetric texture. The formalism is applied to the line shape analysis of Moessbauer spectra of a textured sample of the spin-crossover complex [Fe(mtz)₆](PF₆)₂ (mtz = 1-methyltetrazole). It is found that between 185 and 240 K the rate constants for the HS → LS conversion are temperature independent, whereas an Arrhenius behaviour is found for the LS → HS conversion

[en] Specific nonvalent interactions (SNI) with participation chalcogene atoms in structures on the basis of (μ₃-X)(μ₂-X₂)₃M₃⁴⁺ and (μ₃-X)(μ₂-X)₃M₃⁴⁺ (M = Mo, W; X = O, S, Se) were considered. SNI classification was carried out. The determining role of SNI during crystal structure formation was shown

[en] Binuclear molybdenum(0) carbonyl complexes were synthesized based on naphthophosphacyclophanes containing a 1,6-dihydroxynaphthalene fragment and diethylamide linkers. The physicochemical and spectral characteristics of the synthesized coordination systems were studied.

[en] The modern state of the theory of the mutual influence of ligands (MIL) has been analyzed and conclusions from the different MIL models have been compared with experimental data concerning the central atom-ligand bond lengths. It is shown that in complexes of both transition and main group elements the predominant type of the directed influence of ligands is the trans-influence, though in some cases, especially for main group element complexes, the MIL regularities are of a more complicated character. (author)

No abstract available

[en] The method of qualitative comparison of effective charges of metal atoms in transition element complexes on the basis of comparison of metal oxidation degree and electronegativity of metals and ligands is described. Examples of influence of effective charge of metal atom on the structure of a number of complexes of rhenium, technetium, molybdenum and some other transition elements are given

No abstract available

[en] Mixed-valence μ-phenolate-bis(μ-carboxylate) diiron(II, III) complex [Fe₂(bpmp)(ppa)₂](BF₄)₂ (1) is prepared. The temperature dependence of the Moessbauer spectra of the complex 1 is measured. The Moessbauer parameters of the complex 1 show the unusual increase of isomer shift and quadrupole splitting with an increase in temperature. The spectra are explained by the dynamic electronic states in which the valence states of two iron atoms in a molecule are 2.2 and 2.8 on the Moessbauer time scale at 293 K. The single crystal X-ray structure of the complex 1 is determined at 133 K. The complex 1 crystallizes in the triclinic space group P-bar 1. Two iron atoms in the complex 1 are crystallographycally inequivalent. (author)

No abstract available

[en] The rhenium complexes is a radiopharmaceutical in nuclear medicine. The stability of rhenium compounds in crystal is studied based on the reformed packing model. The structural data of 406 rhenium compounds containing no metal-metal bonds are collected. The sums of their solid angle factor (SAF) are calculated and statistically analysed. It turns out that the stability center is 0.951 +- 0.084. The value of 2σ is comparable to the SAF of a common coordinating atom. This result means that the packing of the coordinating atoms around the central atom is restricted by geometrical factors