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2 | . // Tomsk State Pedagogical University Bulletin. 1999. Issue 7 (16). P. 16-20 . | 855 | ||||
3 | . // Tomsk State Pedagogical University Bulletin. 1999. Issue 7 (16). P. 21-23 . | 900 | ||||
4 | Some problems of a modern state of the theory of the molecule structures surveyed. The concepts about a method of molecular orbitals and most important parameters are given: electronic density, order of bonds, index of free valence. The possibilities of modern quantum-chemical calculations are shown. | 934 | ||||
5 | The calculations clearly show that the calculated by B3LYP/II and B3LYP/3-21G* 35CI frequencies correlate with the experimental values are the same. On the other hand the QCC values calculated with use of the pseudo potential for the central atoms provided much lower than the experimental ones. At the same time the QCC values of the central atoms calculated by B3LYP/3-21G* were well correlated with experimental values. The ZPE corrected complexation energies of the SbCI5L complexes do not upgrade the binding energies towards the experimental Gutmann's donor numbers. The donor-acceptor bonds for all complexes have a high degree of ionic character. The Wiberg bond order values determine of the detection of the metal-ligand bond orbitals with the exception of niobium complexes by NBO approach. The value of Wiberg bond order must be not lesser than 0.3. The donor-acceptor interactions of main-group elements such as Sb and Sn described in terms of the sp hybridization just as these interactions of transition metal elements mean sd hybridization. | 969 | ||||
6 | The semiempirical PM3 method was applied for analysis of such experimental parameters as NQR frequencies, energy levels in X-ray electron and X-ray fluorescence spectra. The subjects of the study were complexes of tin and antimony. The strong correlation established between the differences in the energies in the inner energy levels of tin, antimony, chlorine atoms and the corresponding ClKa shifts. The obtained correlation dependencies can be used for the characterisation of the donor ability of ligands. | 1060 | ||||
7 | The research of electronic absorption spectrums and thermal parameters of dichloride copper complexes with various organic ligands is conducted. Were obtained of correlation dependencies between wave distances, temperatures of one ligand molecule sepa¬ration and calculated ligand donor ability by PM3 method. On the basis of experimental performances the spectrochemical number of the ligands was determined. The reference of the researched complexes to orbital-controlled was conducted. | 904 | ||||
8 | In this paper ab initio HONDO calculations of SnCI4, SbCI5 and TiCI4 with H2S complexes have been per¬formed. All 35CI-NQR frequencies for above-men¬tioned nv-complexes are obtained by ab initio calcula¬tions. It was shown that ab initio calculations might be useful for the appropriate interpretation of experimen¬tal NQR frequencies. The optimized geometry of the complexes has been used to calculate the quadruple coupling constants, the ionization potentials, the MO composition and the orbit¬al energies for each of the compounds investigated. Our calculations have been pointed out that TiCI4, SnCI4 and SbCI5 complexes are somewhat stabilized. The most stable complex is SbCI5 that is in a good agreement with the experimental data. The stability of the complexes depends both on the stabilization of the occupied donor molecular levels and the vacant ac¬ceptor and donor levels. | 875 | ||||
9 | The Becke's hybrid method with the different correlation functionate has been used for the calculation of nuclear quadrupole coupling constants (NQCC) for the large number of molecules containing 9 various quadrupole nuclei. Electric field gradients were calculated at various ievels of DFT approach: B3LYP/ 6-31+G(df,pd), B3LYP/cc-pVTZ, BHandHLYP/aug-cc-pVTZ, B3LYP/3-21G(d). The nuclear quadrupole moments of oxygen, fluorine, chlorine, nitrogen, boron, aluminum, arsenic, niobium and antimony isotopes v/ere calibrated | 940 | ||||
10 | The hybrid Baker’s method together with the cor-relative functional by Lee, Young and Parr was used for constants calculation of the quadric field interaction of the compound sets of cooper, silver and gold. The results were compared with the data of microwave spectroscopy in the gas phase. The authors analyzed the quality of calculation with the use of pseudo-potential and widened basis conditions for cooper compounds. On the base of Messebauer spectroscopy and the aforementioned calculation of the input of the atom orbit of gold and the importance of Messenbauer chemical shift | 953 | ||||
11 | The analysis of an electronic structure of the boron and aluminum halogenide complexes was carried out on the basis of the density functional theory. The parameters of NQR spectra calculated with use all electronic basic set compared with the experimental values. Is found out, that NQCC of the quadrupole atoms calculated on the base of the extended basic set is in an insignificant deviation from the experimental values. The bonding of an element - chlorine and element - ligand in complexes with use natural orbital bond was analyzed | 961 | ||||
12 | The paper presents the optimization of the molecular geometry of metallocenes by two different density functionals. The resulting structural and spectral data are compared with the experimental values. The conclusion is based on the calculation method of the natural valence orbitals of the value of the magnitude of the donor-acceptor and dative interactions in the formation of metallocenes. Following the procedure of decomposion of the energy, the values of the ionic and covalent character of bonds between the metal and carbon atoms were calculated. Keywords: density functional theory, metallocenes, ionic and covalent character of bonds | 1007 | ||||
13 | The use of situational problems in the study of methods of teaching chemistry at a pedagogical university is described, and their significance in training of students for professional activity is characterized. The definition and the structure of the situational task is given, its components are singled out. Specific features of differentiated questions to the texts of situational tasks and their use in the training process is described, the character of the cognitive activity of the students when performing different tasks are singled out, specific examples of tasks are given. The availability of the content of the tasks for students, the features of the choice of differentiated tasks, the conditions for their fulfillment, as well as the students’ interest in creative cognitive activity are revealed on the basis of the questionnaire. The tasks of the first level are aimed at reproduction of theoretical knowledge, in the process of their implementation, the reproductive nature of students’ activity prevails.. These tasks are used to repeat theoretical material in practical exercises, seminars or remotely. They contribute to the formation of practical skills and the skills in drawing up summaries of lessons and didactic materials. Tasks of the second level of complexity allow you to integrate materials from different educational areas, which are necessary to solve certain situations. When performing such tasks, the partial search character of students’ cognitive activity predominates and practical skills and skills in developing and compiling methodological materials are improved. Tasks of the third level of complexity develop the ability to analyze information, generalize and systematize it, draw conclusions based on the initial data and justify them. At the same time, there is a deepening and further development of the skills in developing didactic materials, taking into account modern requirements for school chemical education. When performing such tasks, the search activity, creative and authorial approach dominates and the originality in their solution is manifested. Keywords: competence approach, methods of chemistry teaching, situational task, task structure, questions of the first, second and third levels of complexity to the content of the situational tasks, specific features of differentiated tasks, questioning of students | 1084 |