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Two packing polymorphs of 5-hydroxy-1-(4-methylbenzyl)-3-chloro-4-[(4-chlorophenyl)sulfanyl]-1,5-dihydro-2H-pyrrol-2-one are studied by single-crystal and powder X-ray diffraction, IR spectroscopy, and differential scanning calorimetry. Classical hydrogen bonds and CL…O interactions have the fundamental importance for the formation of the supramolecular motif that is identical in both modifications. The difference relates to the packing of 2D layers which is “parallel” in the triclinic modification and of the “herringbone” type in the monoclinic modification. It is shown that close similarity between structural organizations of crystal lattices, which is typical of packing polymorphs, can be accompanied by significant differences between their energies as well as by a high potential barrier upon the transition from the metastable polymorph to its stable form.

This paper presents the results of a comparative study of rock samples from depth intervals of 1705–1728 m of Semilukian–Mendymian (domanik) deposits of the Berezovskaya area and 1379–1394 m of carbonate (domanikoid) deposits of the Dankovian–Lebedyanian horizon of the Zelenogorskaya area of the Romashkino oilfield. It has been shown that rocks with different mineral compositions differ in the content and composition of organic matter (OM), including kerogen, and its resistance to thermal impacts. The yield of extracts from the rocks and the differences in their group, structural-group, and hydrocarbon-group compositions have been determined. According to the molecular-mass distribution of normal and isoprenoid alkanes, the extracts from the rocks are oils of types A1 and A2. Peculiarities in the distribution of higher biomarkers have been revealed, indicating that the hydrocarbons of the examined samples of domanik and domanikoid rocks are genetically uniform in nature, but differ in the geochemical environment of the transformation of the original OM and, possibly, in the effect of migration processes.

Using a complex of physical and chemical methods studied features of the elemental, structural-group, and microelement composition of natural bitumen asphaltenes extracted from bituminous r...

The spectral, aggregation, and adsorption properties of amphiphilic metal complexes of alkylated N-methyl-D-glucamines and lanthanum nitrate and their mixture with hexadecyltrimethylammonium bromide were studied using IR, UV, and 1H NMR spectroscopy, tensiometry, potentiometry, and dynamic and electrophoretic light scattering. The parameters of aggregation and adsorption at the interface were determined and compared with the parameters of the ligands, ligand–inorganic salt mixtures, and traditional cationic surfactants.

Study was conducted of rocks composition and its extracted moving hydrocarbons from Domanic deposits of Tatarstan, differing in location and occurrence depth from 1379 to 1891 m. The rocks are repr...

This work deals with polyfunctional biocompatible amphiphilic isatin derivatives. Isatin-3-acylhydrazones containing a quaternary ammonium moiety (Is-Q-n) with varying hydrophobicity (R = CnH2n+1, where n = 10, 12, 14, 16, 18, 20) were synthesized. Tunable self-assembly behavior, morphology of nanostructures, and their biological activity were modulated by hydrophilic-lipophilic balance of π-amphiphiles and solvent polarity. Self-assembly of Is-Q-n was investigated by tensiometry, conductometry, IR and UV–Vis spectroscopy, fluorimetry and dynamic light scattering. The unexpected values of the physicochemical parameters at long alkyl chain length have been interpreted. The CAC of Is-Q-16 is lower than CMC of classical surfactant CTAB. Solvent-induced self-assembly for Is-Q-16 was observed. The hydrophobic dye Orange OT was solubilized in Is-Q-10 solutions twice better than in CTAB solutions. Is-Q-n self-assembled structures with size 50 nm and 100 nm in a concentration range from 0.01 mM (below CAC) to 10 mM were found. Is-Q-10 forms small associates with size 3 nm. Selective antimicrobial activity of low toxic ammonium salts against Gram-positive bacteria (S. aureus 209p and B. cereus 8035) and fungus Candida albiсans 855–653 was shown. Newly synthesized 1-dodecylisatin derivatives containing a quaternary ammonium moiety may be recommended as antimicrobial agents and for drug solubilization, in particular for drugs capable for π-π stacking interactions.

Hydrogen bonds and structure of drug Xymedone in different phase and aggregate states were studied using IR and Raman spectroscopy, IR microscopy, quantum chemical calculations (B3LYP/6-31G*), X-ray powder diffractometry, and DSC and TGA methods. It was found that the synthesized specimen of Xymedone powder is a mixture of two gauche-conformers. First one is bound by intermolecular hydrogen bonds and second one is stabilized by an intramolecular hydrogen bond. Upon the dissolution of Xymedone the conformational equilibrium shifted in favor of conformers of the first or second type depending on the solvent nature.

The IR and Raman spectra of P 0 ′ and P 4 ′ dendrimers built from an octasubstituted metal-free phthalocyanine core with oxybenzaldehyde terminal groups have been recorded. The phthalocyanine core was used as a probe for analyzing the properties of the internal structure. The structural optimization and normal mode analysis were performed for P 0 ′ dendrimer on the basis of the density functional theory (DFT). It was found that the P 0 ′ molecule exists in a stable conformation with planar phthalocyanine core. The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. The experimental IR spectra of P1 dendrimer were interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The difference IR and Raman spectra of molecules built from the thiophosphoryl and phthalocyanine cores with the same repeating units and terminal groups were studied in order to underline the role of the core functionality on the dendrimer architecture.

Peculiar features of the molecular structure, isomeric composition, and hydrogen bonding in new, potentially physiologically active γ-oxime alkylphosphonates were established.

As is known [1, 2] dimephosphon is successfully used for the treatment of various disorders, which suggests that this compound influences the key points common in the main metabolic processes. This conclusion stimulates investigations aimed at elucidation of the universal mechanism of drug action at the molecular level. Based on an analysis of data on the effect of dimephosphon on the aggregation of thrombocytes and the functional-metabolic activity of leukocytes, it was suggested [3] that such a universal mechanism can be related to the drug effect on the relative content of calcium ions in the intraand extracellular medium. In recent years, experiments using direct measurement of the Ca ion dynamics in the intracell medium showed that DMP increases the level of calcium ions in the cell by stimulating their release from intracellular depots [4]. In this context, we have studied the possibility that dimephosphon participates in the molecular biological processes via interaction with calcium ions and their environment.

Crystalline specimens of homochiral and racemic glycidyl p-toluenesulfonate were studied by IR spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis. The melting phase diagram of glycidyl p-toluenesulfonate was constructed. The stacking effect in the crystals of the racemic sulfonate is responsible for a more dense molecular packing, with the result that a heterochiral type of crystallization becomes more favorable.

The reaction of [60]fullerene with diphenylphosphinoyl azide in toluene or ino-dichlorobenzene in the presence of traces of water affords 2-[N-(diphenylphosphoryl)amino]-1-hydroxy[60]fullerene This reaction in THF gives a mixture of (N-diphenylphosphoryl)[60]fullerenol[1,2-b]aziridine and a product of partial hydrolysis of the bisadduct of phosphorylated azide and fullerene.

The reactions of phosphine derivatives of diallyl isocyanurates with palladium(ii) dichloride lead to the formation of complexes, whose structure, composition, and stability depend on the length of the methylene chain between the isocyanurate and diphenylphosphine fragments in the ligand. 1,3-Diallyl-5-[5′-(diphenylphosphino)pentyl and 10′-(diphenyl-phosphino)decyl] isocyanurates with PdCl2 form monomeric L2PdCl2trans-complexes in which P atoms of the ligands participate in coordination with the metal. 1,3-Diallyl-5-[2′-(diphenylphosphino)ethyl] isocyanurate with PdCl2 forms a dimeric (LPdCl2)2 complex, which decomposes in a solution to the monomer including solvent molecule into the coordination sphere of the metal. The reactions of 1,3-diallyl-5-[4′-(diphenylphosphino)butyl] isocyanurate and 1,3-diallyl-5-[6′-(diphenylphosphino)hexyl] isocyanurate with PdCl2 give monomeric chelate LPdCl2 complexes in which one of the allyl groups of the isocyanurate cycle participates in coordination with the central ion along with the phosphorus atom.

New arsenic (III) derivatives of 4-methoxyphenyldithio- and trithiophosphonic acids were obtained in the reactions of LawessoN′s reagent with arsenic (III) alkoxides.

Investigations into the quantitative structure-activity relationship (QSAR) have now became widespread because this analysis allows us to assess the role of various structural factors determining a given type of activity and to perform theoretical screening of chemical compounds and select the most promising structures. In some cases this approach allowed researchers to predict and then synthesize new compounds possessing a higher activity as compared to that of the substances included in the teaching set [I]. Historically, the original approach most widely used until now is that suggested by Hansch [2]. This method is based on regression analysis and is capable of establishing statistically significant dependences for further use in the theoretical screening. In recent years, the significance of descriptors such as hydrophobicity is frequently evaluated by theoretical methods referred to as molecular modeling. For this purpose, a substrate molecule is superimposed onto the target molecule using computer-simulated structures of the Stewart-Brigleb models. This procedure allows the degree of complementarity of the two structures to be determined and the role of various factors in the intermolecular interaction to be assessed [3, 4]. Because the spatial structure of a target molecule is by no means always known, an alternative procedure may be that based on studying the spatial structure of substrate molecules [5]. This approach proceeds from the concept of maximum correspondence of the active functional groups (atoms) of the substrate molecule to important parts of the target molecule ("keylock" fitting principle). One significant problem involved in this investigation is related to the fact that the calculation is performed for free molecules rather than for a substrate target complex. Evidently, the most stable conformation of a free molecule will not necessarily coincide with the configuration providing a satisfactory contact. Indeed, some

Acetaldehyde and butyraldehyde azines and 1,2-bis(tert-butylimino)ethane add only one molecule of dialkyl H-phosphonate at room temperature to form alkyl (α-aminoalkyl)phosphonates. IR spectra of compounds obtained are discussed.

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 reaction of [60]fullerene with diphenylphosphinoyl azide in toluene or ino-dichlorobenzene in the presence of traces of water affords 2-[N-(diphenylphosphoryl)amino]-1-hydroxy[60]fullerene This reaction in THF gives a mixture of (N-diphenylphosphoryl)[60]fullerenol[1,2-b]aziridine and a product of partial hydrolysis of the bisadduct of phosphorylated azide and fullerene.

The drug, dimephosphone, in aqueous media has two most probable conformers. The formation of hydrogen bonds with water and complexes with SnCl4 in acetonitrile involves the phosphoryl oxygen atom. Complexation favors some of the dimephosphone conformers.

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.

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.

The reaction of dialkyl H-phosphonates with pyridine-3-carbaldehyde gives alkyl (3-pyridyl)hydroxymethylphosphonates. In liquid systems, the hydrogen atom is localized at the oxygen atom of the hydroxyl group; in crystals, the existence of a zwitter-ionic form could not be excluded. In CHCl3 solutions, isolated molecules and cyclic dimeric H-complexes exist in an equilibrium.

This paper presents the results of investigations of the manifestations of photostimulated structural changes in thermally deposited layers of As2Se3 from the absorption spectra in the far-IR region, using the methods of Fourier spectroscopy. It is shown that photostructural changes in the layers used for fabricating the holograms show up in an intensity redistribution of the bands of the IR absorption spectrum associated with the valence vibrations in moleculelike pyramidal structures that form part of the unit cells of the crystalline phase of As2Se3. © 2005 Optical Society of America

Acetaldehyde and butyraldehyde azines and 1,2-bis(tert-butylimino)ethane add only one molecule of dialkyl H-phosphonate at room temperature to form alkyl (α-aminoalkyl)phosphonates. IR spectra of compounds obtained are discussed.

Data on the structure of cycloadducts of organophosphorus dipolar reagents and fullerenes arc absent, to our knowledge. We died the reactions and the shucturc of cycloadducts of phosphorylated azidcs and nitrile oxide with [60]fullcrcnc. The cycloaddition of diphcnylphosphinic llzide to fullcrme has bcm determined to lead to the 1 -[(N-diphenylphosphoryl)amino]-2-hydroxy[6O]hllcrme (l), the mixhuc of phosphorylated aziridinofullcrcne (2) and derivative of fullerne (3) with one aziridine fragment and one aminohydmxy-fragment, or to product (4), depending on the conditions of don .

The molecular mechanics method has been used to determine the equilibrium geometric parameters of 39 conformations of the 1,3,2,6-dioxaphosphazocine molecule, among which the preferred form is the boat-boat (BB) conformer with C and O atoms at the vertices. The role of the anomeric effect in stabilizing the axial orientation of the P-S bond has been evaluated quantitatively in various conformers on the 1,3,2,6-dioxaphosphazocine molecule.

1. 2-Chloro-1,3,2-dioxaphosphepane exists as at least two confomers or groups of conformers which are in thermodynamic equilibrium. 2. For 2-chloro-1,3,2-dioxaphosphepane, 11 conformers are possible. The most probable equilibrium forms were chosen from a comparison of the experiment and the calculation. 3. The predominant ring conformation in the case of d,1-2-chloro-4,7-dimethyl-1,3,2-dioxaphosphepane is similar to the ring conformation of 2-chloro-1,3,2-dioxaphosphepane and has 4e,7e orientation of the CH3 groups. The meso form of 2-chloro-4,7-dimethyl-1,3,2-dioxaphosphepane has predominantly a chair form with 4e,7e substitution.

1. The existence of a thermodynamic equilibrium between the trans and gauche conformers in ethyldichlorophosphonate, ethyldichlorothiophosphonate, and ethyldichloroselenophosphonate has been established. 2. The gauche conformer predominates in compounds I–III at 298°K. In the case of ethyldichlorophosphonate the trans isomer remains in the solid phase, in the thio analog the gauche isomer remains, and in the selenium analog the trans and gauche isomers remain. 3. The experimentally observed difference in the frequencies of the conformers is close to that calculated under the assumption that their force fields are constant. Nevertheless, the frequencies of the stretching vibrations of the multiple bonds are higher in the trans isomers than in the gauche. 4. One vibration with predominant participation of the P=X bond (ν P=O,ν P=S, andν P=Se) has been isolated in the spectrum of each conformer. The characteristic nature of the vibrations for the bonds just cited decreases along the series indicated.

1. The IR and Raman spectra of 2-seleno-2-chloro- and 5,5-dimethyl-2-seleno-2-chloro-1,3,2-dioxaphosphorinane in different solvents, phases, and at difference temperatures have been studied. 2. A calculation of the frequencies and modes of the normal vibrations of 2-seleno-2-chloro-1,3,2-dioxaphosphorinane has been made. 3. The studied molecules under the experimental conditions were conformationally uniform.

1. According to a calculation by the methods of molecular mechanics, the realization of only one conformation with an axial P-Cl bond is possible for 2-chloro-1,3,2-dioxaphospholane and 2-chloro-1,3,2-dithiaphospholane in accordance with the experimental data. In 2-chloro-1,3, 2-dioxaphospholane this form is close to an envelope with an 0 atom departing from the plane of the other four atoms in the ring (a-Eo), and in the dithia analog a conformation which is close to an envelope with a C atom departing from the plane (a-Ec) is realized. 2. According to the data from the calculation, 2-chloro-1,3,2-oxathiaphospholane should exist in the form of ana-EC ⇄ e-Ec mixture of conformers (or with the participation of twist forms).

1. An equilibrium of conformers with gauche- and trans-orientation of the P = S and OCH3 groups in the gas and liquid phases follows from the vibrational spectra and dipole moments of methyldichloro-thiophosphate. A trans-conformer is realized in the crystalline state. 2. The IR and Raman spectra of methyldichlorothiophosphate were interpreted on the basis of a calculation of the frequencies and forms of the normal vibrations considering possible rotational isomers.

1. The IR and Raman spectra of the methyl selenophosphonates and methyl selenophosphinates: (CH3O)2P(Se)CH3, CH3OP(Se) (C2H5)2, and CH3OP(Se) (C6H5)2 were studied in various phase states and in solvents, and with a variation in the temperature. The vibration bands of the P=Se group were assigned. 2. A thermodynamic equilibrium of at least two steric forms of the molecule was detected in the first two compounds. The isomers arise as the result of one methoxy group rotating from the gauche position with respect to the P=Se bond to the trans position, with a gauche orientation of the other groupings. 3. The relative amount of the isomers in the mixture and the thermodynamic parameters of the equilibrium were determined. 4. The steric conditions created by the two aryl radicals in the third compound lead to a stabilization of one predominant conformer in all of the states of the compound, with a gauche orientation of the OCH3 with respect to the P=Se bond.

1. The 2-seleno-2-methyl- and 2-seleno-2-methyl-5,5-dimethyl-1,3,2-dioxaphosphorinanes in the liquid state (melt) and in solution exist as a mixture of two conformers with the structure of a distorted chair, which differ in the orientation of the P=Se bond. The energetically more favorable and quantitatively predominant, and also realized in the crystal, is the less polar form with an axial P=Se bond. 2. The vibrational spectra of the indicated compounds were interpreted on the basis of the experimental data and calculation.

1. The molecular dipole moments (DM) of the 26 studied selenophosphoryl compounds vary in the range 2.70–6.65 D. The reasons for the changes in the DM are discussed. 2. The dipole moments of the P=Se bond displays a greater variability than do P=S and P=O. According to the obtained and literature data, the polarizability and coordination character of the P=X bond changes in the order: P=Se> P=Se> P=O.

1. According to their vibrational spectra, 2-X-2-methyl-l,3,2-dioxaphosphorinanes (X=O, S, Se), exist in the liquid phase in the form of a thermodynamic equilibrium between two chair forms with axial (a) and equatorial (e) orientations of the P=X double bond. The equilibrium is strongly shifted in one direction or another, depending on the medium and the structure. 2. Within the framework of the reactive field theory, changes in the enthalpy differences of thea− and e-forms have been calculated for the transition from liquid to solutions; these values are consistent with the experimentally measured values. Also, temperature-corrected values of ΔH have been determined.