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Using a combination of physicochemical methods (dynamic and electrophoretic light scattering (DLS and ELS, respectively), nanoparticle tracking analysis, atomic force and transmission electron microscopy (AFM and TEM, respectively), UV spectroscopy, conductometry, pH-metry, dielcometry), it was found that dilute solutions of a multicomponent drug immunomodulator polyoxidonium (PO) are nanoheterogeneous disperse systems, with their disperse phase undergoing considerable restructurings when diluting the solution in the range of calculated concentrations from 1∙10–1 to 1∙10–16 mg mL–1, which is reflected in the non-monotonous concentration dependencies of specific electroconductivity, dielectric permittivity, and pH of the solutions. Using ELS, AFM, TEM, and UV spectroscopy methods, it was found that the disperse phase with a size of hundreds of nanometers which forms at concentrations of ≤1∙10–5 mg mL–1, contains organized water structures substantiating the negative values of ζ-potential, which vary non-monotonously from–5 to–16 mV. Radioprotective properties of dilute solutions of PO (1∙10–1 and 1∙10–9 mg mL–1) were demonstrated for the first time when exposing the test mutant bacterial strain Salmonella typhimurium TA 100 (Ames test) to X-ray radiation in a dose of 7.50 mGy used for medical diagnostics.

A number of 2-methylthio-6-methyl-4-alkyl- and alkylaminopyrimidines, as well as their salts produced by the reaction with methyl p-toluenesulfonate and trifluoroacetic acid, were investigated. The quantum chemical and experimental IR and Raman spectral methods were used to determine the preferential isomeric forms of the molecules of studied compounds, whose convenient spectral markers were revealed. The starting pyrimidines and their salts were found to exist predominantly as an amino form. The salt formation proceeds via the methylation (protonation) of the N1 atom of pyrimidine ring.

Replacement of terminal atoms of Br in 1,3-bis(bromopentyl)-5(6)-substituted uracils with 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptoimidazole, and 2-mercaptobenzimidazoles resulted in a series of acyclic compounds and isomeric heterocyclophanes. Structures of macrocyclic regioisomers were unambiguously determined by NMR data. One of the regioisomers exhibits a hypochromic effect with respect to model compounds. The acyclic uracils obtained bridged with five-membered heterocycles are alkylated with methyliodide and methyl tosylate, and oxidated with m-CPBA, H2O2, and I2.

It is demonstrated that dissolution of aminothiacalix[4]arene in chloroform results in transformation of 1,3-alternate conformation, adopted in single-crystal and bulk polycrystalline solids, to the pinched-cone form. This conformer is stabilised by the intramolecular hydrogen bonds of two distal amino-groups acting as H-donors with another two amino moieties that appear as H-acceptors. The H-bonds cause quite small (ca. 10-20 cm(-1)) red shift of the IR bands of the NH(2) stretching vibrations, which suggests rather weak NHcdots, three dots, centeredN hydrogen bonding. This latter is sufficient to stabilize the pinched-cone conformation in the chloroform solution, but the energy gap between the pinched-cone and other conformations is small, and solid-state intermolecular forces easily overcome it, leading to realisation of the 1,3-alternate conformer. The comparison of the DFT computed and experimental vibrational and NMR spectra demonstrates good quality of present quantum-chemical computations, allows complete interpretation of the spectra and reveals simple IR and NMR spectroscopic markers of the conformers of aminothiacalix[4]arenes.

Bis(hydroxymethyl)phosphinic acid and melamine were shown by FTIR and UV spectroscopy to form the salt (melafen), whose cations and anions involving water molecules can be joined into supramolecular structures due to electrostatic interactions and hydrogen bonds. The conductometry, dielcometric titration, and dynamic light scattering methods showed that melafen in water and chloroform in a concentration range of 10−10–10−4 mol L−1 involving the solvent structures exist as supramolecular polymeric nanostructures, whose size and properties change nonlinearly depending on the melafen concentration.

Reaction of α,ω-bis(3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)alkanes with paraformaldehyde leads to pyrimidinophanes, which contain four 3,6-dimethyluracil fragments, connected to each other by the methylene chains. A comparative study of intra- and intermolecular interactions of “open” and macrocyclic uracil derivatives in the crystal state and in solution was performed. According to the NMR spectroscopy data, there is no self-association of “open” and macrocyclic compounds in chloroform solutions, whereas the X-ray data revealed the intermolecular π-π contacts between the 3,6-dimethyluracil fragments in the crystals of these compounds. Conclusions on the presence of intramolecular interactions in chloroform solutions of α,ω-bis(3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)alkanes and pyrimidinophanes were made based on the UV spectra, which were interpreted in terms of hypo- and hyperchromic effects relatively to the model uracil derivative. These conclusions correlate with the X-ray data: there are no intramolecular π-π contacts between the 3,6-dimethyluracil fragments both in the crystals and in solutions of “open” compounds, positions of these fragments relatively to each other in the molecules of pyrimidinophanes are defined by the lengths of the polymethylene bridges. The intramolecular stacking effect between the opposite uracil rings is observed for the macrocycles with trimethylene and hexamethylene chains, whereas there is no such interactions in pyrimidinophanes with tetramethylene chains.

Molecular structure and vibrational spectra of 2-trichloromethyl(ethoxycarbonyl)-1-nitroethenes and 2-trichloromethyl(ethoxycarbonyl)-1-bromo-1-nitroethenes were calculated in terms of the density functional theory (B3LYP/6-31G*). The experimental FTIR spectra of these compounds in the range from 4000 to 400 cm−1 were interpreted in detail on the basis of the calculation data. 2-Substituted 1-nitro- and 1-bromo-1-nitroethenes were assigned the structure with trans orientation of the nitro and trichloromethyl (or ethoxycarbonyl) groups, and the ethoxycarbonyl derivatives were assumed to exist in equilibrium between s-cis and s-trans conformers.

New amphiphilic pyrimidinic macrocycles (APMs) with two (APM-1) and three (APM-2) decyl tails have been synthesized by quaternization of the bridged N. Complex examination of the APM-based systems with the help of tensiometry, conductometry, dynamic light scattering, and UV and NMR spectroscopy provides evidence for their aggregation. Calculations based on surface tension isotherms and on packing parameter considerations make it possible to assume a lamellar packing of macrocycles when aggregating. Marked differences in the aggregation behavior of APM-1 and APM-2 have been found. The additives of polyethylenimine (PEI) exert little influence on the critical micelle concentration (cmc) of APM-1, while in the APM-2/PEI systems there occurs a pronounced decrease in the cmc and also a ca. 2-fold decrease in the surface area per molecule. The APM-based assemblies are explored as nanoreactors for the hydrolysis of O-alkyl O-p-nitrophenyl (chloromethyl)phosphonates (alkyl = ethyl, hexyl). The kinetic study reveals a minor rate effect of the APM-1-based systems. In the APM-2-based systems an acceleration of the hydrolysis of both phosphonates occurs as compared to the uncatalyzed process. Within the APM-2 --APM-2/PEI --APM-2/PEI/La(III) series, due to the cooperative contributions of the supramolecular, polymer, and homogeneous catalysis, an increase in the catalytic effect is observed from 30 times to 3 orders of magnitude as compared to that of the basic hydrolysis of the substrates.

The oxidative dehydrocyclization of the 3-(indolizin-2′-yl)-2-oxoquinoxaline monopodand performed either electrochemically or under the action of molecular iodine affords new redox-active heterocyclophane consisting of the redox-switchable biindolizine fragment combined with the polyether-bridged π-deficient quinoxaline systems. The single-crystal X-ray diffraction study showed that the trioxaundecane chain of heterocyclophane adopts an extended conformation, and one of the phenyl substituents of the molecule closes the pseudocavity formed by the spacer from one of the sides. The cyclic voltammetric study of heterocyclophane in MeCN and DMF showed the three-step oxidation of the indolizine fragments accompanied by the single-electron transfer in each step. The first and third steps are reversible, and the second step is irreversible. The oxidation at potentials of the first peak gives rise to stable radical cations detected by the ESR method (g = 2.0024, a 2N = 0.26 mT).

A series of acyclic compounds with two 3,6-dimethyluracil or 3-methyluracil units attached to a a thymine or isocyanurate fragment by polymethylene or xylylene spacers are investigated. Ring-closure reactions with paraformaldehyde in aqueous HCl in the presence of copper(I) chloride afforded pyrimidinophanes which can be considered macrocyclic counterparts of the acyclic triuracils. By X-ray diffraction data the structures of the macrocycles in the solid state are characterised by a close arrangement of the uracil units, but there are no π-π contacts between them. On the contrary, significant hypochromism of the macrocyclic triuracils compared with their acyclic counterparts indicates stacking between the thymine and 3,6-dimethyluracil units in chloroform and H2O solutions. The conformational behaviour of the acyclic and macrocyclic compounds in solution has been determined by NMR, UV and computational methods. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Complexes of copper(II) bromide with cyclic and isostructural acyclic phane ligands containing derivatives of pyrimidine nucleobases (cytosine and uracil) were synthesized and characterized. In two cyclic pyrimidinophanes used, the macrocycles included two 6-methylthiocytosine and one 6-methyluracil units linked by polymethylene chains (L3) and two 6-methyluracil units linked by N-containing bridges (L5). Ligand L3 and its isostructural acyclic analogs are coordinated by the Cu2+ ion through the same donor sites (the ring N atoms of the thiocytosine units). The coordination polyhedra of the Cu atom in complexes with cyclic and acyclic ligands are different. Ligand L5 and its isostructural acyclic analog also form copper(II) complexes with different coordination polyhedra involving different donor sites. The acyclic ligand is coordinated by the Cu2+ ion via the bridging N atom, while cyclic ligand L5, via the uracil CO groups (the bridging N atoms become protonated). The resulting complexes are dielectrics.

Intra-and intermolecular interactions in acyclic compounds containing nucleotide base (uracil and thymine) derivatives and their macrocyclic analogs (pyrimidinophanes) were studied by IR, UV, luminescence, and NMR spectroscopy. Molecules of these compounds include one or two N3-methylsubstituted or N3-unsubstituted uracil fragment or two adenine fragments linked through a hexamethylene spacer to an uracil, 5,5′-methylenediuracil or diphenylmethane fragment. The examined compounds almost all are characterized by π-π interactions and intramolecular hydrogen bonding between the terminal uracil or adenine fragments. Intramolecular association constants were determined and factors affecting them were discussed. Complex formation of acyclic and macrocyclic ligands with adenine and thymine derivatives was studied. The low values of the association constants were interpreted in terms of a competition between intra-and intermolecular bonding and very labile ligand structure.

Aggregation of amphiphilic calix[4]resorcinarenes (CRA) modified by carboxymethyl (1), 2-hydroxyethyl (2), methylamino acetal (3), and aminomethyl (4) fragments and their interaction with some synthetic (5, 6) and natural (7, 8) surfactants in the low-polarity solvent (chloroform) were studied by permittivity measurements and FT-IR spectroscopy. Compounds 1–4 and surfactants form aggregates at critical micelle concentrations (CMC) of 2.0·10−5–7.5·10−5 and 1.7·10−5–2.0·10−3 mol L−1, respectively. The CMC values of CRA—surfactant mixed aggregates depend on the surfactant structure and the structure and concentration of CRA. Analysis of the IR spectra of solutions of a series of amphiphilic CRA (2–4, 9, 10) and their mixtures with the cationic surfactant N-cetyl-N,N-dimethyl-N-(2-hydroxyethyl)ammonium bromide (5) showed that an increase in the concentration of the solutions in individual and mixed systems is accompanied by a decrease in the molar integral intensities and intensities in the maxima of the absorption bands of the O—H and C—H bonds down to the CMC point, after which these values change slightly. The discovered effect, which is differently pronounced for all systems studied, indicates that both the polar “head” groups and nonpolar fragments of CRA and surfactant are involved in the formation of supramolecules of the reverse micelle type in all cases.

A method for the synthesis of new calix[4]resorcinols tetra-3,5-di-tert-butyl-4-hydroxybenzyl derivatives is developed. Their interaction with methyldichlorophosphonate, dimethyldichlorosilane in the presence of a base leads to formation of organophosphorus-organosilicon cavitands. Acetylation of hydroxybenzylated calix[4]resorcinols with acetic anhydride leads to products of either incomplete or full acetylation depending on experimental conditions.

Isomeric pyrimidinophanes containing uracil moieties and nitrogen atoms in bridges have been synthesized and characterized by a variety of methods both in solid and in solution. Unambiguous assignment of mutual arrangement of C(4)pyrO groups at different pyrimidine rings in isomers is made by X-ray diffraction. In solutions the arrangement of C(4)pyrO groups of the isomeric pyrimidinophanes results in different dipole moments. Based on dipole moments simulations mutual orientation of uracil units in isomers is analysed. UV-data are discussed in terms of hypo- or hyperchromic effect.

The molecular and crystal structure of N,N′-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)urea has been established by single crystal X-ray diffraction and IR spectroscopy. There were also investigated intermolecular hydrogen bonds in its crystal and solutions.

The reactions of 1,3-bis(5-bromopentyl)-5-methyl-or 1,3-bis(5-bromopentyl)-6-methyl-uracil with benzylamine afforded pyrimidinophanes containing the nitrogen atom in the polymethylene bridge. Single-crystal X-ray diffraction study and NMR and UV spectroscopic study in solution demonstrated that the phenyl and uracil fragments in the macrocycles are in spatial proximity. Unlike the known macrocycles containing the pyrimidine ring, the pyrimidinophanes under study are conformationally rigid.

Acyclic and macrocyclic compounds having different numbers of pyrimidine fragments and nitrogen atoms in the polymethylene bridges or in substituents at the pyrimidine rings reacted with 2,3,5,6-tetrachloro-1,4-benzoquinone and 1,4-benzoquinone according to the charge transfer scheme to give products with an ionic structure. The reaction was accompanied by protonation of nitrogen atoms in the polymethylene bridges or in substiuents at the pyrimidine rings and reduction of 2,3,5,6-tetrachloro-1,4-benzoquinone or 1,4-benzoquinone to 2,3,5,6-tetrachlorobenzene-1,4-diol or benzene-1,4-diol, respectively. The isolated products are dielectrics.

A new type of macrocycle containing 2-thio-4-aminopyrimidine and 6-methyluracil moieties has been studied by IR and UV spectroscopy. The vibrational spectra, conformations and amine–imine tautomerism of the aminopyrimidine fragments have been analysed within the framework of ab initio MO theory (HF/6-31G**, MP2/6-31G**) and density functional theory (B3LYP/6-31G**). According to experimental and theoretical results, the amino form is preferred in these compounds. Both intra- and intermolecular hydrogen bonds of the type NH⋯N are present in crystals, whereas in solutions, conformational equilibria with free NH groups are also obtained.

The molecular and crystal structure and the hydrogen bonding in crystal and in solutions of N-phenyl-N-(3,5-di-tert-butyl-4-hydroxybenzyl)thiourea and N-(3,5-di-tert-butyl-4- hydroxybenzyl)thiourea were studied by single crystal X-ray diffraction and IR spectroscopy. The intermolecular interactions of these compounds are essentially different.

The IR and Raman spectra and conformations of the ionic liquid 1-ethyl-3-methyl-1H-imidazolium tetrafluoroborate, [EMIM][BF4] (6), were analyzed within the framework of scaled quantum mechanics (SQM). It was shown that SQM successfully reproduced the spectra of the ionic liquid. The computations revealed that normal modes of the EMIM+ (.) BF4- ion pair closely resemble those of the isolated ions EMIM+ and BF4-, except for the antisymmetric BF stretching vibrations of the anion, and the out-of-plane and stretching vibrations of the H-C(2) moiety of the cation. The most plausible explanation for the pronounced changes of the latter vibrations upon ion-pair formation is the H-bonding between H-C(2) and BF4-. However, these weak H-bonds are of minor importance compared with the Coulomb interactions between the ions that keep them closely associated even in dilute CD2Cl2 Solutions. According to the 'gas-phase' computations, in these associates, the BF4- anion is positioned over the imidazolium ring of the EMIM+ cation and has short contacts not only with the H-C(2) of the latter, but also with a proton of the Me-N(3) group.

The reactions of 3-benzoylquinoxalin-2-one and its N(1)-alkyl derivatives with 1,2-phenylenediamines were accompanied by ring contraction as a result of the quinoxaline-benzoimidazole rearrangement giving rise to 2-benzoimidazolyl-substituted quinoxalines. The possible pathways of these reaction are discussed.

A series of conformationally heterogeneous and energetically multilevel ω-diphenylphosphoryl- and ω-diphenylthiophosphoryl-substituted aliphatic alcohols, whose molecules are capable of five-, six-, and seven-membered ring closure due to the OH...O=P or OH...S=P intramolecular hydrogen bond (IHB), was studied by IR spectroscopy and molecular mechanics. The data obtained confirm the previous assumption that the energy of IHB (E IHB) differs substantially from the difference of enthalpies of conformers with and without IHB (–ΔH ), which is experimentally determined by the temperature dependence of the intensity of IR ν(OH) absorption bands. The measured –ΔH values can be positive, zero, or negative at significant IHB effects, i.e., at high Δν(OH) and E IHB values.

The conformations and vibrational spectra of 2-benzylphenol have been analysed within the framework of scaled quantum mechanics. It is shown that the solid-state conformation of the 2-benzylphenol molecule corresponds to one of four potential energy minima predicted by non-empirical quantum chemical calculations for the isolated molecule. In the molten state and in diluted CCl4 solutions of the title compound this conformer coexists with another two spectroscopically detected conformations. The presence of several conformers gives rise to the observation of the corresponding number of vsCH2 and vasCH2 bands in the IR spectra, thus providing experimental evidence of the conformational sensitivity of the vCH2 frequencies. It is shown that vCH2 wavenumbers of different kinds of molecules, containing diphenylmethane fragments, are determined by the dihedral angles between the planes of the aromatic rings and the plane of the connecting methylene bridges, except for the case of short intramolecular contacts with the participation of the methylene protons.

3-Benzoyl-1,2-dihydroquinoxalin-2-one reacts with hydrazine and thiosemicarbazide to give the corresponding hydrazone and thiosemicarbazone. The reaction with arylhydrazines yields 3-(α-arylazobenzylidene)-1,2,3,4-tetrahydroquinoxalin-2-ones which are tautomeric to the respective arylhydrazones. On heating in boiling acetic acid, the products of both types undergo intramolecular cyclocondensation with formation of 3-phenylpyrazolo[3,4-b]quinoxalines (3-phenylflavazoles). 3-Benzoyl-1,2-dihydroquinoxalin-2-one thiosemicarbazone gives rise to flavazole structure only in the presence of methyl 3-chloro-2-oxo-3-phenylpropionate as a trap of thiocarbamoyl moiety. The cyclization of 3-(α-hydrazonobenzyl)-1,2-dihydroquinoxalin-2-one is accompanied by formation of quinoxalyl ketone azine.

The reactions of 1,3-bis(ω-bromobutyl- or -pentyl)-6-methyluracil with 1,3-bis(ω-ethylaminobutyl- or -pentyl)-6-methyluracil afforded pyrimidinophanes containing N atoms in bridging polymethylene chains. Individual geometric isomers of pyrimidinophanes were isolated. The structure of one of these isomers was established by X-ray diffraction analysis. Quaternization of the bridging N atoms with o-nitrobenzyl bromide gave rise to water-soluble pyrimidinophanes.

Acyclic and cyclic counterparts containing thymine and two 3,6-dimethyluracil fragments bridged by methylene chains have been prepared and studied by UV and NMR spectroscopy; in water the uracil units of the acyclic counterpart form an intramolecular stack but arrange in a linear array in chloroform while the fragments of the uracilophane form an intramolecular stack both in chloroform and water; uracil units of bis(3,6-dimethyluracil-1-yl)butane and the macrocyclic counterpart form a stack in chloroform.

A new macrocycle including pyrimidine fragments, 12,23,36-trimethyl-24,40-dioxo-15,33-dithia-2,9,13,22,26,35,38,39-octaazatetracyclo[32.3.1.110,14.122,26]tetraconta-1(38),10(39),11,13,23,34,36-heptaene, was synthesized. According to the data of IR and UV spectroscopy and HF/6-31G** quantum-chemical calculations, macrocyclic compounds of this series in crystal exist in the amino form, one NH group of which is likely to be involved in intramolecular hydrogen bond, and the other, in intermolacular hydrogen bond. The strength of the latter depends on the macroring size. In solution, the above structures are supplemented by conformers containing both intramolecularly H-bonded and free amino groups, predominantly with trans structure of the HANACIN fragment. The imino form of the aminopyrimidine moieties is hardly probable.

The conformations and vibrational spectra of bis(2-hydroxyphenyl)methane have been analysed within the framework of density functional theory. The calculated force fields (B3LYP/6-31G*) of seven possible energy minima were transformed to internal coordinates, and a set of ten different scaling factors was applied. The scaled quantum mechanical (SQM) method reproduces the experimental IR and Raman spectra with high accuracy. The dependence of the CH2 stretching vibrations on the conformation and the possibility of its use as a probe for larger systems, e.g., calixarenes or polyphenols, are discussed.

IR and Raman spectroscopy, normal coordinate analysis, and molecular mechanics were used to study the conformations of Cl(CH 2 ) 2 O–PCl 2 molecules. It is shown that gauche conformations of the Cl–CH 2 –CH 2 –O residue are energetically preferred in liquid. These are the only conformations remaining in the low temperature crystals, anti conformations being “frozen out”. In these crystals the POCC residue most probably adopts an extended conformation, the OC bond being in anti-position relative to the phosphorus lone pair. In the liquid state the extended conformers coexist with the convoluted conformations. Contrary to what might be expected from molecular mechanics considerations the latter conformers are practically as energetically stable as the former. The gap between experimental measurements and the respective molecular mechanics’ estimation is attributed to certain attractive intramolecular 1–5 interactions between the phosphorus and the chlorine atoms. It is used for rough quantitative evaluation of the energy of these interactions, which amount to ∽10–15 kJ mol −1 .

2,4,6-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)resorcinol in the crystal and in solution has a similar steric structure, favorable for its performance as peroxyl radical scavenger.

Esters and amides of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid were prepared by the reaction of furfural with dichloroacetic acid derivatives under the conditions of the Darzens condensation. The structures of the reaction products were confirmed by their1H NMR and IR spectra and chemical transformations.

IR and Raman spectra of 1,4-butanediol (BD) versus variations in the medium (CCl4, CH3CN), concentration, temperature, and phase state were obtained. The observed changes attest to the conformational variety of BD molecules under the experimental conditions. On the basis of the analysis of the v(OH) region it is concluded that both in the gas phase and in CCl4 solution conformers of BD with free OH groups coexist with conformers with O-H...O intramolecular hydrogen bonds. The difference in enthalpies, ΔH, for the groups of conformers with and without intramolecular hydrogen bonds was found from the temperature dependence of the v(OH)free and v(OH)intra band intensities. The structures and energies for 70 possible spectrally and energetically distinguishable conformers of BD that do not take into account intramolecular hydrogen bonds were calculated by molecular mechanics with account of electron lone pairs of oxygen atoms. Using the experimental values of ΔH and the calculated relative conformer energies,E, the intramolecular hydrogen bond energyEintra= 3.7 kcal mol−1 was found.

The methyl ester and N,N-diethylamide of 2-azido-5-phenyl-4-thiazolecarboxylic acid were obtained by the reaction of the corresponding 4-substituted 2-hydrazino-5-phenylthiazole with NaNO2 in acid media. IR and UV spectroscopy were used to show that the compounds synthesized retain azide form in both the crystalline state and in solution. The reaction of azides with dicarbonyl compounds gave derivatives of 2-[5′-methyl-4′-acetyl-or 2-[5′-methyl-4′-ethoxycarbonyl-1′,2′,3′-triazol-1′-yl]-5-phenylthiazole-4-carboxylic acid.

The reaction of (diisopropoxyphosphoryl)nitrile oxide with C60 leads to mono- and diadducts, which are characterized by 1H, 13C, 31P NMR, IR and UV-VIS spectroscopy as isoxazoline derivatives of fullerene; the addition takes place across a 6,6 ring junction.

Electrical and electrooptical characteristics of α-phenoxycyclohexanone, α-phenoxyacetone,p-Me-,p-Cl-,p-Br-,p-NO2-phenoxycyclohexanones, andp-NO2-phenoxyacetone in the solution in CCl4 were determined; these were utilized for the conformational analysis of the general structural fragment Ar-O-C-C=O. The presence of conformers with theac- andsp-structure at the Csp3-Csp2 bond was established in the equilibrium. The content of thesp-form increases with the increase in the polar character of the substituent at thep-position of the benzene ring. Thegauche isomer (sp-G orsp-G′) is realized along the C-O bond in it. In theac-conformers, both thegauche (ac-G) and the trans (ac-T) structures can be realized along the C-O bond.

Electrical and electrooptical characteristics ofα-phenylthioacetone,α-phenylthiocyclohexanone, andα-phenylthio-4-caranone have been determined and used in establishing the structure of the compounds in solution. It has been shown that the preferred conformer with respect to the bond\(C_{sp^3 } - C_{sp^2 } \), is the ac-conformer [ϕ(O=C-C-S)>90°], in which the gauche conformer with respect to the C-S bond is realized, with a 1,3-parallel position of the C=O and S-Ph bonds.

Conformational differences in molecules of 1,3-propanediol with variations of medium, temperature, and phase composition appear in their IR and Raman spectra. In the gas phase and in dilute solutions of 1,3-propanediol in CCl4 forms with intramolecular hydrogen bonding (IHB) and without it exist in comparable amounts. The difference in the weighted mean energies of the corresponding groups of conformers was found from the temperature dependence of the intensities of the bands for free νOH and bounded νOH. By calculating the conformational term of ΔE* and by using the energy values of the 25 conformers of the diol molecules, calculated by molecular mechanics methods, the IHB energy was determined for two of them.

The reaction of (diisopropoxyphosphoryl)nitrile oxide with C60 leads to mono- and diadducts, which are characterized by 1H, 13C, 31P NMR, IR and UV-VIS spectroscopy as isoxazoline derivatives of fullerene; the addition takes place across a 6,6 ring junction.

The IR and Raman spectra and conformations of calix[4]arene, thiacalix[4]arene and their p-tert-butyl derivatives have been analysed within the framework of scaled quantum mechanics (SQM). It is shown that the introduction of four p-tert-Bu groups into the calixarene molecules influences the relative energies of their conformers and the enthalpy of the cooperative intramolecular H-bonding (DeltaH(intra)) almost negligibly. DeltaH(intra), evaluated from Iogansen's rule, amounts to approximately 26-28 kcal mol(-1) for the calixarenes and approximately 20-21 kcal mol(-1) for the thiacalixarenes, which essentially exceeds the enthalpies of non-cooperative H-bonds formed by related phenols. As a result of this strong bonding, bands of stretching, bending and torsion vibrations of an eight-membered cyclic system (OH...)4 arise, e.g., two delta(OH)4 bands are observed in the IR spectra of the most highly symmetric C4 cone conformations of calix[4]arene and thiacalix[4]arene. The "duplication" of the number of OH infrared bands is a good new indicator of cooperativity of intramolecular H-bonding of the calixarenes.

Dialkyl phosphonates bind to the C=N bond of bis(benzylideneimino)toluene, with formation of dialkyl (benzylideneimino)benzylaminobenzyl phosphonates. The complicated character of IR spectra of these compounds is connected with the possibility of formation of dimeric cyclic associates and intramolecular hydrogen bonding. Phosphinic acid reacts with bis(benzylidenimino)toluene in a 2: 1 ratio to affordN,N′-benzylidenebis(α-amino-benzytphosphonic) acid.

Interaction of ethylN,N-(p-methoxybenzal)-p-aminobenzoate with dialkyl phosphonates results in dialkyl (N-p-ethoxycarbonylphenylamino)-p-methoxybenzal phosphonates. In the resulting compounds hydrogen bonds are observed by IR spectroscopy.