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We utilized the OPBE/TZVP (GAUSSIAN-09) hybrid density functional method to compute thermodynamic (full energy; standard enthalpy, entropy, and Gibbs energy of formation) and geometry (bond lengths, bond angles, and torsion angles) parameters of (555)macrotricyclic complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with (NSSN) coordination of the ligand donor centers. Such complexes can be formed upon interaction of hexacyanoferrate(II) of the listed metals, ethanedithioamide, hydrazinomethanethioamide, and ethanedial in gelatin-immobilized matrix implants. Complexes of Cu(II) and Zn(II) are slightly nonplanar, the other complexes are almost flat. In all cases the additionally formed five-membered cycle is practically flat.

The polarity and conformations of 2-aminophenyl-, 2-aminobenzyl-, and 2-nitrobenzyl(diphenyl)-phosphine oxides were studied by the dipole moment method, IR spectroscopy, and quantum chemical calculations. 2-Aminophenyl- and 2-aminobenzyl(diphenyl)phosphine oxides were found to exist preferentially as conformers with intramolecular hydrogen bond. 2-Nitrobenzyl(diphenyl)phosphine oxide is likely to be represented by equilibrium mixture of three conformers in which the phosphoryl and nitro groups are oriented syn or anti with respect to the $PC_{sp^3 } C_{sp^2 } $ fragment.

The geometric parameters of (5656)macrotetracyclic complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with the NNNN-coordination of donor sites of the chelant formed by the template reactions in the M(II)-ethanedithioamide-formaldehyde-ammonia systems have been calculated by the OPBE/TZVP hybrid density functional theory (DFT) method with the use of the Gaussian09 program package. In all complexes, five-membered chelate rings (almost identical to each other in each complex) are nonplanar. For all M(II) ions under consideration, two additional six-membered nonplanar chelate rings formed as a result of template “cross-link” are turned at considerable angles with respect to the five-membered rings. The six-membered rings are located on different sides of the NNNN plane of the nitrogen donor atoms.

Based on the results of a quantum chemical calculation using the DFT method, the possibility of the existence of a zinc complex with phthalocyanine and fluoride ion where oxidation state of zinc is III that is unusual for the given chemical element, have been shown. The data on the key structural parameters and multiplicity of the ground state of this complex have been presented, too.

The polarities of 2-chloro-N-(2-((diphenylphosphoryl)methyl)phenyl)acetamide and 2-chloro-N-(2-((diphenylthiophosphoryl)methyl)phenyl)acetamide were determined, and conformational analysis of these...

Using density functional theory (DFT) at the OPBE/TZP level, the calculations of geometric parameters of the molecular structures of M(II) metalmacrotetracyclic complexes with tetradentate chelate ligand with (NNNN)-coordination of donor centers and with four five-membered metal-containing rings formed as the result of “self-assembly” processes in the M(II)–dithiooxamide–2-hydroxysubstituted acetaldehyde systems were carried out. The calculations for a “template” ligand from the inner coordination sphere of these metal complexes were also performed. Bond lengths, bond and torsion angles in the formed coordination compounds, as well as values of standard enthalpy, entropy, and Gibbs’s energy for each of them are presented.

The geometric parameters of the molecular structures of M(II) (5555)macrotetracyclic complexes with a tetradentate (NNNN) macrocyclic ligand, formed by template reactions in the systems M(II)-ethanedithioamide-ethanedial-1,2-ethenediol systems, as well as of the molecular structure of the template ligand forming the coordination sphere of these complexes, have been calculated by the OPBE/TZVP density functional theory method. The bond lengths and bond and torsion angles in the complexes, as well as the standard enthalpies, entropies, and Gibbs energies for each of them, are reported.

Using density functional hybrid DFT method in its OPBE/TZVP option, calculation of the geometric parameters of molecular structures of M(II) (5456)macrocyclic chelates with tetradentate macrocyclic ligand – 7-imino-1-oxa-3,6,8,11-tetraazacyclododecanetetrathione-4,5,9,10 with (NNNN)-coordination of donor centers arising as a result of template synthesis. The values of the bond lengths, bond and torsion angles in the resulting complexes are presented. The values of the standard enthalpy, entropy and Gibbs energy of formation of these compounds were also calculated.

Conformational analysis of N-arylmaleimides and bis-maleimides was performed by the dipole moment method and quantum chemical calculations. The aromatic ring and heterocycle in N-arylmaleimides are turned with respect to each other through an angle of 42–44°, which excludes conjugation between these fragments. No conjugation exists between the dioxopyrrole rings in bridged bis-maleimides. The structure of the examined compounds is controlled by steric factors. Pronounced inductive effect of chlorine atoms in chloro-substituted bis-maleimides is responsible for their reduced dipole moments.

The geometric parameters of the molecular structures of M(II) (5456)macrotetracyclic complexes with a tetradentate (NNNN) macrocyclic ligand, formed by template reactions in the quaternary systems M(II)-2-amino-2-thioxoacetamide (H2N-C(=S)-C(=O)-NH2)-aminomethanamidine (H2N-C(=NH)-NH2)-methanal (formaldehyde, CH2O) (M = Mn, Fe, Co, Ni, Cu, and Zn), as well as of the molecular structure of the template ligand per se, have been calculated by the OPBE/TZVP density functional theory method. The bond lengths and bond and torsion angles in these complexes have been reported. The standard enthalpies, entropies, and Gibbs energies of formation of these compounds have been calculated.

The thermodynamic and geometric parameters of M(II) macrotetracyclic chelates (M = Mn, Fe, Co, Ni, Cu, and Zn) with the (NNNN) coordination of the donor ligand sites, formed by the complexation reactions of corresponding M(II) compounds, ethanedithioamide H2N-C(=S)-C(=S)-NH2, and acetone H3C-C(=O)-CH3 in gelatin-immobilized matrix implants have been calculated by the OPBE/TZVP density functional theory method with the use of the Gaussian 09 program package. The bond lengths and bond and torsion angles in these complexes have been reported. It has been shown that despite the fact that the MN4 chelate core in them is almost planar, the five- and six-membered chelate rings are pronouncedly non-coplanar. In the Mn(II), Fe(II), Co(II), and Ni(II) complexes, these chelate rings are pairwise identical, whereas in the Cu(II) and Zn(II) complexes, they are noticeably different.

Diphosphorus-substituted isoxazole and 1,2,3-triazole were synthesized by a click chemistry method. Their polarity and structure were determined by the dipole moment method and quantum chemical calculations.

Polarity and structure of ethyl α-nitrocinnamates have been studied by means of dipole moments method and quantum-chemical calculations. These compounds exist in the form of Z-isomers in solution, that is, nitro group and benzene ring are cis-positioned.

Using density functional theory (DFT) at the OPBE/TZP level, the calculation of the geometric parameters of the molecular structures of M(II) (5456)macrotetracyclic complexes with a tetradentate macrocyclic ligand with (NNNN)-coordination of donor centers, resulting from template reactions in M(II)- thiooxamide- guanidine-formaldehyde quaternary systems, where M= Mn, Fe, Co, Ni, Cu, Zn was performed. The calculation of the molecular structure of this “template” ligand itself was also carried out. The values of the bond lengths, bond and torsion angles in the resulting complexes are presented. The values of the standard enthalpy, entropy and Gibbs free energy of formation of these compounds were also calculated.

Enthalpies of the C−N bond dissociation of nitrobenzene and twenty-seven mono substituted nitrobenzenes along with their formation enthalpies were calculated using different multilevel (G2, G3, G3B3, CBS-QB3) and density functional theory-based B3LYP and wB97XD techniques. The gas phase enthalpies of formation of mono substituted phenyl radicals were also calculated using these methods. The calculated values of reaction enthalpies were compared with available experimental data. We have concluded based on results of present and recent article, that B3LYP level of theory with 6-31G(d′f,p′) basis sets should proposed as the accurate method for calculating formation enthalpies of mono substituted nitrobenzenes as well as enthalpies of C–NO2 bond scission. Based on satisfactory correlation between experimental and calculated data we proposed revision of experimental activation energy of C–NO2 bond rupture in o-chloronitrobenzene, o- and m-nitrotoluene as wells as p-nitroaniline. Enthalpies of formation of some substituted phenyl radicals were estimated using experimental enthalpies of C–NO2 bond cleavage together with formation enthalpies of mono substituted nitrobenzenes and NO2 moiety.

Comparative stability of three types of (565)macrotricyclic chelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with chelate nodes MN2S2 and MN4 have been analyzed by means of hybrid density functional method B3LYP with the 6-31G(d) basis set using GAUSSIAN-09 software. These chelates may potentially be formed in template interaction between gelatin-immobilized hexacyanoferrate(II) of respective metal ions M(II), thiosemicarbazide H2N-HN-C(=S)-NH2, and formaldehyde H2C=O. It has been demonstrated that for all M(II) considered, the complex with chelate nodes MN2S2 is more stable. Key structural parameters of the complexes (bond lengths, bond and torsion angles) are presented. It is noted that pseudotetrahedral coordination of ligand donor centers around M(II) is typical for Mn(II), Co(II), Cu(II), and Zn(II), whereas for Fe(II) and Ni(II) it is almost planar. Values of standard enthalpy ΔHf,2980 and standard Gibbs energy ΔGf,2980 are positive for nearly all the complexes studied.

Enthalpies of formation of twenty seven mono substituted nitrobenzenes were calculated employing various DFT and composite methods using atomization approach and two types of isodesmic reactions. The overall best agreement with experiment was achieved by using Gn multilevel techniques. It was found that the best performance among DFT methods within atomization approach demonstrates long range corrected wB97XD level theory. The average absolute deviation value calculated for B3P86/6-311G(d,p) which have been recently reported as an very accurate method for calculating formation enthalpies of poly and mono substituted nitrobenzenes exceeds 50 kcal/mol. Employing of isodesmic reactions tends to it improve estimations of DFT levels, though agreement between theoretical data obtained using this methodology with experiment depends strongly on the type of reaction and the quality of experimental Δ f H 0 ,298 values available for compounds involved in these bond balanced reactions.

The geometric parameters of the molecular structures and thermodynamic parameters of formation of macrotricyclic M(II) complexes (M = Mn, Fe, Co, Ni, Cu, and Zn) with the MN2S2 coordination core formed by the reactions of corresponding hexacyanoferrates(II) with hydrazinecarbothioamide H2N-HN-C(=S)-NH2 and 2,4-pentanedione H3C-C(=O)-CH2-C(=O)-CH3 in gelatin-immobilized matrix implants have been calculated by the B3LYP hybrid density functional theory method with the use of the 6-31G(d) basis set and the Gaussian 09 program package. The bond lengths and bond and torsion angles in these chelates have been reported. It has been shown that the Fe(II) and Ni(II) complexes are strictly planar, whereas the Mn(II), Co(II), and Cu(II) complexes are quasi-planar with a rather small deviation of the MN2S2 chelate core from coplanarity, and only the Zn(II) complex is pseudotetrahedral. The additional sixmembered chelate rings resulting from the above processes are almost planar in all chelates.

The article represents the results of research in self-organization of new lanthanide systems in water-decanol medium. The systems are based on N,N-dimethyldodecylamine oxide, a zwitterionic surfactant. The study covers the complex formation of lanthanide ions with C12DMAO molecules and the influence of Ln(III) ions and medium composition on surfactant association in diluted solutions. The analysis of adsorption isotherms was carried out on the basis of the combination of Gibbs and Langmuir adsorption equations. The results were used to determine physicochemical properties and parameters of a monomolecular adsorption layer. The research objects were various lanthanide ions with identical coordination centers. A number of spectroscopic methods (UV, NMR self-diffusion, EPR, dynamic light scattering (DLS), and fluorescent analysis) were involved in the research for comparative estimations of molecular dynamics, critical micellization concentration, geometry, sizes, and aggregation numbers of micellar aggregates. Micelle structure simulation revealed good agreement between experimental data and quantum chemical calculations.

Synthesis of new calix[4]resorcinol molecules with acetal groups on the upper rim associated with calixarene skeleton through γ-aminoalkyl spacers was performed. The condensation of the compounds studied with 2-methylresorcinol was studied.

The thermodynamic and geometric parameters of the macrocyclic chelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with the (NNNN) coordination of the ligand donor centers formed upon complexation between the above metal ions, hydrazinomethanethiohydrazide (H2N-HN-C(=S)-NH-NH2), and 2,3-butanedione (H3C-C(=O)-C(=O)-CH3) in gelatin-immobilized matrix implants were calculated by the B3LYP 6–31G(d) density functional theory method with the use of the Gaussian 09 program package. The bond lengths, valence angles, and torsion angles were reported, and it was noted that the complexes of Fe(II), Co(II), Ni(II), and Cu(II) are almost planar, whereas the complexes of Mn(II) and Zn(II) have a quasi-pyramidal structure of the chelate unit. The additional six-membered metallocycles resulting from template cross-linking, as well as five-membered rings, are almost planar.

A novel one-pot synthetic approach to N1-(2-carboxyaryl)-N2-(aryl or H)oxalamides from 3-(2-nitroaryl)oxirane-2-carboxamides via the classical Meinwald rearrangement and a new rearrangement sequence has been developed. The methodology is applicable to the synthesis of N-(2-carboxyphenyl)aryloxalmonoamides from (3-(2-nitrophenyl)oxiran-2-yl)(aryl)methanones. The method is operationally simple and high yielding, thus providing a new useful formula for both anthranilic acid derivatives and oxalamides.

Thermodynamic and geometric parameters have been calculated using the hybrid density functional theory method B3LYP with the 6-31G(d) basis set and the Gaussian03 program for the macrotricyclic complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with an (NSSN)-coordinated ligand that can result from the complexation of metal hexacyanoferrates(II) with hydrazinomethanethioamide H2N-HN-C(=S)-NH2 and ethanedial HC(=O)-CH(=O) in gelatin-immobilized matrix implants. Bond lengths and valence and torsion angles in these complexes are reported. The Ni(II) and Cu(II) complexes are practically planar. The Mn(II), Fe(II), and Co(II) complexes are characterized by a small deviation from coplanarity, and the Zn(II) complex is noticeably noncoplanar. The additional five-membered metallacycle resulting from template “joining” is nearly planar in all complexes.

Conformational analysis of 1,3,2-dioxaphospholan-2-yl 2,2,2-trifluoroacetate and 4,5-benzo-1,3,2-dioxaphosphol-2-yl 2,2,2-trifluoroacetate was carried out using the method of dipole moments and quantumchemical calculations (DFT B3LYP/6-31G*). Both compounds are found to exist as an axial conformer with preferably syn arrangement of the carbonyl group and the lone electron pair.

The geometric parameters of the macrotricyclic CoII, NiII, CuII, and ZnII chelates with (NSSN) coordination of the donor centers of the ligand, which are formed by complex formation between the metal ions, hydrazinomethane thioamide H2N-HN-C(=S)-NH2, and butane-2,3-dione Me-C(=O)-C(=O)-Me in aqueous solutions and gelatin-immobilized matrix implants, were calculated using the DFT B3LYP hybrid method in the 6-31G(d) standard basis set and the Gaussian03 program. The bond lengths, bond and torsion angles in the coordination compounds are presented. All the complexes are nearly planar.

The geometric parameters of M(II) complexes (M = Mn, Fe, Co, Ni, Cu, and Zn) with chelating ligands 1-hydrazino-4,6,6,12-tetramethyl-2,3,7,8,10,11-hexaazatridecatetraene-1,3,8,11-dithiol-1,9 and 2,8,8,10,16-pentamethyl-3,4,6,7,11,12,14,15-octaazaheptadecapentaene-2,5,10,12,15-dithiol-5,13 with the NNSS coordination self-assembled in the M(II)-hydrazinomethane thiohydrazide-acetone systems have been calculated by the hybrid B3LYP density functional theory method with the use of the 6-31G(d) basis set and the Gaussian 03 program package. The bond lengths and bond and torsion angles in these complexes have been reported. It has been stated that, in the complexes formed by the same M(II) ion, these characteristics are close to each other. For all M(II) ions under consideration, an additional six-membered chelate ring resulting from template cross-linking is turned to the two five-membered rings and is nonplanar as distinct from the latter.

Polarity of 2-(1-methylbenzimidazol-2-yl)-1-phenyl- and -1,2-diphenyl-1-nitroethenes was determined and their structure was studied using electronic and 1H, 13C NMR spectroscopy, dipole moments measuring, XRD analysis, and quantum-chemical calculations. It was shown that the 2-(1-methylbenzimidazol-2-yl)-1-nitro-1-phenylethene has Z-configuration both in crystal and solution. The nitro group and benzimidazole substituent in its molecule are removed from the plane of the double bond. For 1,2-diphenyl-1-nitroethene E-structure is typical.

Present theoretical study has been carried out with objective to reveal effect of chlorine and fluorine substituents on C–N bond strength in nitromethane. Gn, W1 and CBS-QB3 composite techniques were employed to compute accurate values of formation enthalpies of halogenated nitromethanes, corresponding radicals and ΔrH0(C–N) values. Calculations on DFT and ab initio levels were performed using B3LYP and QCISD methods. It was found that substitution of hydrogen by fluorine atoms causes only slightly decreasing of ΔrH0(C–N), whereas accumulation of chlorine atoms tends to decrease C–N bond strength significantly. Formation enthalpies of halogenated nitromethanes and corresponding radicals were calculated using both atomization approach and involving isodesmic reactions.

The thermodynamic and geometric parameters of isomeric macrotricyclic Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes with the (NSSN) coordination of the ligand donor centers formed in the reaction of corresponding hexacyanoferrates(II) with ethanedithioamide H2N-C(=S)-C(=S)-NH2 and ethanedial HC(=O)-CH(=O) in gelatin-immobilized matrix implants have been calculated by the hybrid B3LYP density functional theory method with the use of the 6–31G(d) basis set and the Gaussian 03 program package. The bond lengths and bond and torsion angles in these complexes have been reported, and it has been stated that the Mn(II), Co(II), and Cu(II) complexes are nearly planar, the Fe(II) and Ni(II) complexes are slightly nonplanar, while the Zn(II) complex exhibits a rather considerable deviation from coplanarity. The additional five-membered chelate ring resulting from template cross-linking is almost planar in all cases.

Geometric parameters and formation enthalpy and the enthalpy of the radicals formed during the homolytic breakage of C-NO2 bond in 37 aromatic nitro compounds were calculated using different bases of the hybrid density functional method B3LYP, as well as the composite CBS-QB3 methods. On the basis of thermochemical data, were calculated the C-NO2 bond dissociation energy and the activation energy of the radical gas-phase decomposition. Donor substituents were shown to cause an increase in the C-NO2 bond dissociation energy, while the acceptors decrease it. The values of activation energies of gas-phase decomposition of aromatic nitro compounds calculated basing on the C-NO2 bond dissociation energy are in good agreement with experiment.

In recent paper we reported results concerning the gas phase enthalpies of formation of C1–C4 mononitroalkanes calculated using different multilevel and density functional theory (DFT)-based B3LYP techniques. The enthalpies of the C−N bond dissociation of these nitroalkanes had been also calculated. In present paper calculated activation enthalpies and enthalpies of reaction for HONO elimination from C2–C4 mononitroalkanes are represented. DFT/B3LYP, ab initio QCISD levels of theory together with G3, G3B3 G4 and CBS-QB3 were employed in this study. G4 calculated enthalpies of formation and reaction enthalpies of C–N bond rupture are performed in addition to activation and reaction enthalpies for HONO elimination. Comparison with available experimental activation energies showed that G3 and G3B3 estimations are of higher accuracy. The agreement of the CBS-QB3 calculations with experiment is also satisfactory. G4 calculated data demonstrated the worse agreement and did not produce correct trends for reaction enthalpies of C–N bond rupture.

The structure of some six- and eight-membered phosphorus and silicon heterocycles was established by the method of dipole moments and density functional theory calculations. There are two necessary conditions for the feasibility of the transannular interaction in these heterocycles: (1) the favorable disposition of the donor and acceptor centers in a molecule and (2) the presence of the substituents with the considerable polarizing effect at the heteroatom.

Experimental and theoretical conformational analysis of polyfunctional 2-substituted nitroethenes was carried out by the method of dipole moments and density functional theory calculations. It was established that the nitro and ester (or trichloromethyl) groups are trans-arranged in the molecules of 2-trichloromethyl-(ethoxycarbonyl)-1-nitro- and 1-bromo-1-nitroethenes, i.e., nitroalkenes have E-configuration, their bromo-containing analogues have Z-configuration, and s-cis-orientation of the C=C and C=O double bonds is preferred for nitroacrylates. 2,3-Dibromo-3-nitroacrylates have untrivial Z-configuration in solution.

The gas-phase enthalpies of formation of 1,1- and 1,2-dinitroethane and corresponding radical products were calculated using G3B3, CBS-QB3 composite methods and DFT B3LYP level of theory with various basis sets. The enthalpies of the C–N, C–C bonds dissociation and activation enthalpies for HONO elimination were also calculated and compared with available experimental data. It was found that G3B3 calculations do provide a reasonable way to tackle the problem of the decomposition channels of 1,1- and 1,2-dinitroethane. Four main mechanisms for gas-phase decomposition of 1,1- and 1,2-dinitroethane were studied using G3B3 model chemistry. HONO elimination seems to be the most favorable mechanism for the decomposition of 1,2-dinitroethane. However, the difference in energies of the HONO elimination and C–N homolytic bond cleavage in 1,1-dinitroethane does not allow to favor any of these channels, especially at the working temperature. Gauche conformation of 1,2-dinitroethane is calculated to be the lowest-ene...

The gas phase enthalpies of formation of C 1 –C 4 mononitroalkanes were calculated using different multilevel (G1, G2, G3, G3B3, CBS-QB3) and density functional theory (DFT)-based B3LYP techniques. The enthalpies of the C–N bond dissociation of these nitroalkanes were also calculated. The calculated values of the formation and reaction enthalpies were compared with available experimental data. It was found that the G3 and G3B3 procedures gave accurate results for the formation enthalpy of nitroalkanes and radical products. The agreement of the CBS-QB3 calculations with experiment is also satisfactory, whereas less accurate than G3 and G3B3 estimations. The G3 and G3B3 multilevel techniques showed good results for the reaction enthalpies of the C–N bond dissociation.

The structure of the new representatives of polyfunctional bromonitroalkenes, alkyl 2,3-dibromo-3-nitroacrylates, was examined by means of dipole moments, [B3LYP/6-31G(d)] quantum-chemical methods, and IR spectroscopy. They were found to have nontrivial Z-configuration in a solution.

The dipole moments of 6-thia-4,5: 6,7-dibenzo-1,3,2-dioxasilocines were determined experimentally and calculated at the DFT B3LYP/6-31G* level of theory and by the additivity scheme. The experimental and theoretical (DFT B3LYP/6-31G*) conformation analysis of eight-membered 1,3,2-dioxasilocines having planar fragments showed that these compounds in solution exist as boat-chair, boat-boat, or twist-boat conformers, depending on the presence of unsaturated planar fragment, nature of the heteroatom in position 6 of the eight-membered ring, and substituents on the silicon atom.

The complexes of alpha helical polypeptides and individual molecules of water, acetonitrile, and 1,4-dioxane have been investigated. We used 16-mer of polyalanine (PA), polyglutamic acid (PGA) and poly-γ-benzyl-L-glutamate (PBG). Full geometry optimization was performed for polypeptides and their complexes with ligands, each structure has been characterized by the vibrational analysis and the interaction energy including the correction for zero point vibrational energy. Polyalanine creates by single complex with water molecule, acetonitrile, and dioxane. Polyglutamic acid forms five different complexes with water molecule, and three complexes with acetonitrile and two complexes with dioxane. Two complexes of poly-γ-benzyl-L-glutamate with each ligand were found. Carbonyl oxygen of PGA and PBG confirms its strong acceptor character by participation in formation of all obtained complexes with water and acetonitrile. The long side chains of PGA and PBG aid the formation of complexes with two hydrogen bonds where ligand molecule bridges two polar sites of polypeptide. Most of complexes of dioxane with polypeptides are produced due to weak hydrogen bonds of type CH···O. Strong shifts for the stretching vibrations of the interacting group of polypeptides and ligands under the complex formation are detected. Obtained frequencies are in a good agreement with known experimental data. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

Data on the mechanisms of gas-phase monomolecular decomposition of nitroalkanes, nitroalkenes and nitroarenes obtained using modern quantum chemical methods are described systematically. The attention is focused on the discussion of multistage decomposition of nitro compounds to elementary experimentally observed products. Characteristic features of competition of different mechanisms and the effect of molecular structure on the change in the Arrhenius parameters of the primary reaction step are considered.

With the use of a complex of calculation methods the basic thermochemical characteristics of ten standard L-α-amino acids of diaminomonocarboxylic, hydroxyaminomonocarboxylic, and thioaminomonocarboxylic series as well as of a series of heterocyclic amino(imino)carboxylic acids were calculated.

The structure of silatranes N[CH 2 (RMeC 6 H 2 )O] 3 SiR 1 with planar fragments in six-membered semi-rings was established by the methods of dipole moments and density functional theory calculations. They are endo-structures with transannular interaction N → Si in which the oxygen atoms located adjacent to the silicon participate besides the nitrogen and silicon atoms.

For the first time is determined the polarity of eight-membered silocyns with planar fragments. By the methods of dipole moments and theoretical calculations (DFT B3LYP/6-31G*) of 1,3,2-dioxasilocyns is established that in these compounds occurs the conformational equilibrium of the forms bath-chair and distorted bath with the predominance of the first, in this case the bonds C(sp3)-S and C(sp3)-H of the exocyclic MeSCH2 group are in the not eclipsed gauche orientation relative to each other.

Complexation of FeIII, in the form of K[Fe2(CN)6] gelatin-immobilized matrix, in contact with aqueous-alkaline solutions (pH ∼ 12) containing ethanedithioamide-1,2 and formaldehyde, has been studied. Template synthesis leading to a chelate FeIII coordination compound with a tetradentate N,N,S,S-donor ligand identified as 4,4,6-trimethyl-1,9-diamino-1,9-dimercapto-3,7-diazanon-3-en-2,8-dithione and hydroxy co-ligand occurs under these specific conditions. Ethanedithioamide-1,2 and formaldehyde are the ligand synthons in the process studied.

By means of nonempirical and the density functional methods the geometrical parameters, the enthalpies of formation of the compounds and radicals, and the dissociation energies of the N-NO2 bond in primary and secondary N-nitramines were evaluated. The tendencies to the variation of spatial arrangement, of the formation enthalpies, and of the dissociation energies in the series of simplest N-nitramines were analyzed. Alternative mechanisms of the initial stage of the gas phase unimolecular decomposition were considered. It is noted that among all the processes of unimolecular decomposition the formation and destruction of aci-form according to the complex multy-stage mechanism was the most energetically favored.

Using different computation methods main thermochemical characteristics of ten standard L-α-amino acids of monoamino carbonic and monoamino dicarbonic series were obtained.

Geometric parameters of MnII, CoII, NiII and CuII complexes with 1,8-dioxa-3,6,10,13-tetraazacyclotetradecanetetrathione-4,5,11,12 macrohetrocyclic ligand with N,N,N,N-coordination mode, which can be formed as a result of template processes in MII – ethanedithioamide-1,2 – methanal triple systems, were calculated using DFT B3LYP method with 6-31G(d) basic set. Additional 6-membered metal chelate cycles formed as a result of template “stitching” are not planar and considerably tilted in respect to two 5-membered cycles. In addition, in VIV complex, both these cycles are on one side from the mean N,N,N,N-plane formed by coordinating nitrogen atoms, in all other complexes – on different sides of this plane.

By means of hybrid method of the density functional B3LYP with 6-31G(d) basis set we carried out calculation of geometric parameters of Co(II), Co(III), Ni(II) and Cu(II) complexes with macrocyclic ligand formed at the template processes in the systems M(II)-dithiooxamide-acetone with NNSS-coordination of donor centers. Atomic coordinates, bond lengths, bond angles and dihedral angles in the complexes with metallochelate node MN2S2 are listed. In the cases of Ni(II) and Cu(II) this chelate node is practically planar while in the case of Co(II) is tetrahedral. An additional six-membered metallocycle formed as a result of template “stitching” is screwed and turned by enough significant angle relative to five-membered rings.

The method of dipole moments and theoretical calculations (DFT B3LYP/6-31G*) were used for structural assessment of silatranes N[CH2(RMeC6H2)O]3SiR1 containing planar fragments in the six-membered semirings. They are endo structures with transannular N→Si interaction which involves, along with nitrogen and silicon, oxygen atoms adjacent to silicon.