Predicting discotic mesomorphism from molecular parameters for discogenic structures

Molecular parameters (M_m, M_r, K_p, K, K_c, and K_s) are calculated for polysubstituted cycloveratrilenes and cyclophanes as a continuation of our series of papers on prediction of discotic mesomorphism (DM). Histograms showing the distribution of 57 mesogenic and 28 nonmesogenic structures according to the first three parameters are constructed. Prediction probabilities are estimated at more than 50% for M_m and M_r. This approach is used to analyze 150 hypothetical structures of polysubstituted cycloveratrilenes and cyclophanes to examine the occurrence of a discophase. Several structures with predictable DM are selected for further research. Ivanovo State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 473–477, May–June, 1998.     

On the existence of phases with a structure of NaZr2(PO4)3 in series of binary orthophosphates with different alkaline element to zirconium ratios

Complex phosphates M_xZr_2.25–0.25x(PO₄)₃, where M=Li, Na,K, Rb or Cs and x may be an integer or fraction from 0 to 9, have been synthesized, and their structure has been investigated. The concentration and temperature ranges of stability of the phosphate phases NaZr₂(PO₄)₃ have been found. The influence of the method for the synthesis of these phases and of the annealing temperature on their crystal properties is studied. It was found that the structure of NaZr₂(PO₄)₃ [NZP] exists in the above phosphate series when 0≤x≤5 for Na and K, 0≤x≤3 for Rb, and 0≤x≤1 for Cs. N. I. Lobachevskii Nizhnii Novgorod State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1104–1113, November–December, 1996. Translated by L. Smolina     

Synthesis of 19-substituted steroids of the 16α,17α-cyclohexanopregnane series and study of their interactions with rat uterine cytosol and blood serum proteins

New 16α,17α-cyclohexanopregnanes (pregna-D′₆-pentaranes) containing alkyl or heteroatomic substituents in position 19, namely, 19-methylidene-, 19-methyl-, 19-methoxyimino-, and 19-(3-methoxycarbonylpropoxyimino)-16α,17α-cyclohexanopregn-4-ene-3,20-diones were synthesized, and their interactions with the progesterone receptor and pentarane-binding proteins of rat uterus cytosol and rat blood serum was studied. The same substituent in position 19 of the steroid molecule can affect in opposite direction its affinity to these proteins. These results suggest differences in the structures of the ligand-binding pockets of the three proteins in the region surrounding the C(10) atom of the steroid nucleus. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2579–2584, November, 2005.     

Influence of a water vapor admixture in the carrier gas on capacity coefficients of polar organic compounds

The influence of a water vapor admixture in helium, nitrogen, and carbon dioxide on capacity coefficients of C₃−C₅ alcohols and pyridine during chromatography process in capillary columns with polar (PEG-20M) and nonpolar (SE-30) stationary phases was studied. The introduction of a water admixture into the carrier gas, increases the capacity coefficient of polar organic compounds on the capillary column with PEG-20M and has almost no effect on this value in the case of SE-30. The change in retention of polar organic compounds on the capillary column with the PEG-20M polar phase occurs due to a change in the properties of the stationary phase when it adsorbs water from the mobile phase. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2258–2261, November, 1998.     

Synthesis of unsymmetric triphenylene discotic liquid crystals with a semi-fluorinated chain and the influence of fluorophobic effect on mesogenic behavior

The fluorophobic effect of the semi-fluorinated chain of discotic molecules efficiently improves the stability of columnar mesophase.Low symmetric discogens exhibit decreased melting points and wide mesophase ranges.A series of triphenylene derivatives 1,C18H6(OCnH2n+1)4(OMe)(O2CC2H4C6F13),and their hydrocarbon analogues 2,C18H6(OCnH2n+1)4(OMe)(O2CC8H17),n = 4―8,were synthesized for the investigation of the influence of semi-fluorinated peripheral chain and molecular symmetry on mesomorphism.The structures ...     

Nucleophilic substitution in the series of (1,2,3-triazol-1-yl)-1,2,5-oxadiazoles. Reactions with N-, O-, and S-nucleophiles

Methods for the synthesis of amino(1,2,3-triazol-1-yl)-1,2,5-oxadiazoles (amino-triazolylfurazans) with CH₂Cl and COCH₂Br substituents in the triazole ring were developed and nucleophilic substitution for their halogen atom in reactions with N-, O-, and S-nucleophiles were studied. The possibility of displacing the NO₂ group from the furazan and triazole rings in triazolylfurazans by an azido group was investigated. Novel compounds of this series were synthesized; the reaction rate and pathway were found to depend on the nature of the substrate and the reagent and the position of the substituent in isomers. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1866–1876, August, 2005.     

Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes

Previously unknown 2,3,6,7,10,11-hexakis(dodecyloxy)triphenylene and -(tetradecyloxy)triphenylene were synthesized. The structures of the synthesized compounds were proved by elemental analysis and spectral methods. Polymesomorphism was found for the first time and studied for substances of the hexaalkoxytriphenylene homologic series, as well as liotropic mesomorphism in a series of organic solvents.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1676–1681, August, 2004.     

Spectral and fluorescent properties of cross-conjugated polyene ketones with terminalN-methylpyrrole residues

The spectral and fluorescent properties of a number of cross-conjugated ketones with one or two terminalN-methylpyrrole residues and those of polyene bis-ω, ω′-dimethylamino ketones with methyl substituents in the polyene chain and of some related compounds were studied. The photophysical properties of cross-conjugated ketones with terminalN-methylpyrrole residues are similar to those of the corresponding polyene bis-ω, ω′-dimethylamino ketones studied in detail previously. In both series of compounds, the absorption and fluorescence spectra undergo a bathochromic shift following an increase in the length of the polyene chains or introduction of α,α′-trimethylene or α,α′-dimethylene bridges into these chains; the same trend is observed on passing from less polar solvents to more polar solvents (positive solvatochromism). Thermochromism (long-wavelength shift of the absorption spectra upon cooling the solutions) is observed in both series of compounds. The introduction of methyl substituents into the polyene chains of bis-ω,ω′-dimethylamino ketones results in a decrease in the fluorescence quantum yield. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1293–1298, July, 1999.     

Integral intensities of the absorption bands of the skeletal vibrations of the heteroaromatic ring in the IR spectra of the furanoquinoline alkaloids

1. The integral intensities of the bands of the skeletal vibrations of the heteroaromatic ring in the 1480–1630-cm⁻¹ region of eight furanoquinoline alkaloids have been measured. 2. A connection has been found between the values of ΣA and the structures of the furanoquinoline alkaloids and their derivatives which enables such a series of heteroaromatic compounds to be identified: It has been shown that the introduction of an -OCH₃ group into the γ position of the pyridine nucleus leads to a marked rise (almost twofold) in the value of ΣA;     

Analysis of Solvent–Solvent Interactions in Mixed Isosteric Solvents by Inverse Gas Chromatography

The Flory–Huggins interaction parameter, χ ₂₃, characterizing the interaction between solvents in a mixed stationary phase has been calculated using inverse gas chromatography (IGC). The χ ₂₃ parameters for four mixed solvent systems formed by mixing a non-polar branched alkane, 19, 24-dioctadecyldotetracontane (C78), with four different polar solvents are analysed as a function of temperature. Two of the polar solvents are formed by replacing one of the –CH₃ groups of C78 by –OH (POH) group and –CN (PCN) group and the other two polar solvents are formed by replacing all the four –CH₃ groups of C78 by four –CF₃ (TTF) groups and four –OCH₃ (TMO) groups. The five solvents have similar structures and nearly the same molar volume and in mixtures, they form regular solutions. For the mixture, C78 + POH, χ ₂₃ was calculated at two compositions and for the remaining three mixtures χ ₂₃ was calculated at equimolar composition. Eight solute probes representing all possible chemical structures and polarity were used under conditions approaching infinite dilution. The effects of temperature, concentration of the mixed solvent and probe solute on χ ₂₃ are presented and discussed. The probe-independent χ ₂₃ values were also calculated by linear regression analysis using the retention data of all the solute probes. In all the mixed solvents considered here the χ ₂₃ values are probe-dependent and decrease with increase of temperature.     

Synthesis and characterization of trichlorogermyl dioic acids: crystal structures and complementary hydrogen bonding motifs in 3-(trichlorogermyl) pentanedioic acid and 2-[(trichlorogermyl)methyl]butanedioic acid

A series of trichlorogermyl-substituted dicarboxylic acids of general formula HOOC–R′–COOH where R′=–CH₂CH(GeCl₃)CH₂– 1, –CH(CH₂GeCl₃)CH₂– 2, –CH(GeCl₃)CH₂– 3 and –CH(CH₃)CH(GeCl₃)– 4 were synthesized by the hydrogermylation reaction of unsaturated acids, such as trans-glutaconic (2-pentenedioic acid), itaconic (methylenebutanedioic acid), fumaric (2-butenedioic acid), and citraconic (2-methyl-2-butenedioic acid) acids with HGeCl₃, which was produced in situ by the reaction of GeO₂ with 37% HCl in presence of NaH₂PO₂ · H₂O. All these compounds were characterized by melting point, CHN analysis, FTIR, and multinuclear NMR (¹H; ¹³C; H,H-COSY). X-Ray crystal structures of 1 and 2 were analyzed to show supramolecular structures in which central Ge atom in each of these structures is four-coordinated with a slightly distorted tetrahedral geometry. Structurally, both compounds adopt supramolecular forms via strong intermolecular O–H–O interactions through 8-membered and 22-membered hydrogen bonded rings. Supplementary material to this paper is available in electronic form at Correspondence: Muhammad Mazhar, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.     

Synthesis and electrochemistry of (5Z,5′Z)-2,2′-(alkane-α,ω-diyldisulfanyldiyl)-bis(5-(2-pyridylmethylene)-3,5-dihydro-4H-imidazol-4-one) complexes with cobalt(II ) chloride

A series of S-alkylated 2-thiohydantoin derivatives containing two 5-(2-pyridylmethylene)-2-sulfanyl-3,5-dihydro-4H-imidazol-4-one moieties linked through a polymethylene bridge with different numbers of carbon atoms was synthesized for the first time. These compounds were obtained by the alkylation of 3-phenyl-5-(2-pyridylmethylene)-2-thiohydantoin or 3-methyl-5-(2-pyridylmethylene)-2-thiohydantoin with different α,ω-dibromoalkanes in acetone or DMF in the presence of potassium carbonate. Complexes of these compounds (L) with CoCl₂ were synthesized. In all cases, the complexes L(CoCl₂)₂ were formed regardless of the ratio of L and inorganic salt introduced into the reaction. According to electronic spectroscopic data, the cobalt atom in the complexes has a tetrahedral coordination environment. The synthesized ligands and complexes were electrochemically studied by cyclic voltammetry. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Deceased. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2099–2104, September, 2005.     

A quantitative structure-activity relationship study of antifungal analogues of 3,4-substituted 5-((1H-1, 2, 4-triazol-1-yl)methyl)-4H-1,2,4-triazole

A series of 5-((1H-1, 2, 4-triazol-1-yl)methyl)-4H-1,2,4-triazole derivatives were prepared and evaluated for their antifungal activities. Quantitative structure–activity relationship studies were performed on these compounds using physicochemical parameters as independent parameters and antifungal activity as a dependent parameter, where antifungal activity correlated best (correlation coefficient r > 0.8) with physicochemical parameters (Hammett’s constants σ _p , F) and van der Waals volume V ₁. Results are interpreted on the basis of multiple regression and cross-validation methodology. Furthermore, the domain of applicability which indicates the area of reliable predictions is defined. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Chemical structures of A1–26 and A39; synthetic procedures; synthesis schemes; mps, yields, ¹H NMR; elemental analyses of compounds and single crystal X-ray diffraction of compounds.     

Synthesis and properties of crystalline fullerene hydrides

The interaction of crystalline fullerence C₆₀ with highly pure hydrogen, which was evolved from hydrides of intermetallic compounds of rear-earth metals and nickel, was studied. Crystalline fullerene hydrides containing from 10 to 30 hydrogen atoms per fullerene molecule were synthesized (1.0–2.5 MPa and 300–673 K). Crystalline hydrides release hydrogen at 800 K with retention of the structure of the fullerene molecule. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2093–2096, October, 1998.     

Synthesis and mesomorphism of mixed ether-ester tail triphenylene discotic liquid crystals with long alkyloxy peripheral chains

Symmetrical and asymmetrical triphenylene discotic liquid crystals with two kinds of different peripheral chains, sym-TP(OC₁₁H₂₃)₃(O₂CR)₃ and asym-TP(OC₁₁H₂₃)₃(O₂CR)₃, (R=CH₂OC₂H₅, CH₂OC₃H₇, CH₂OC₄H₉, CH₂OC₅H₁₁, C₃H₇, C₄H₉, C₅H₁₁, C₆H₁₃, C₇H₁₅) were synthesized. Their thermotropic liquid crystalline properties were studied by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The results showed that the asymmetrical compounds had higher melting and clearing points than that of their corresponding symmetrical compounds. For the same series of compounds, TP(OC₁₁H₂₃)₃(O₂CR)₃, their melting points decrease and clearing points increase gradually with the lengthening of ester chains. Most of the β-oxygen containing esters of triphenylene derivatives, TP (OC₁₁H₂₃)₃(O₂CR)₃, (R=CH₂OC₂H₅, CH₂OC₃H₇, CH₂OC₄H₉, CH₂OC₅H₁₁), symmetrically or asymmetrically attached on triphenylene cores, have higher melting and clearing points than those of triphenylene derivatives, TP(OC₁₁H₂₃)₃(O₂CR)₃, (R=C₄H₉, C₅H₁₁, C₆H₁₃, C₇H₁₅), with the same length of peripheral chains. The triphenylene derivatives with longer peripheral chains have shown mesophase at room temperature. __________ Translated from Chemical Research and Application, 2007, 19(10) (in Chinese)     

Synthesis and properties ofN-[1-hydroxyimino-2-methyl-1-(2-pyridyl)prop-2-yl]hydroxylamine and heterocyclic derivatives based on it

N-[1-Hydroxyimino-2-methyl-1-(2-pyridyl)prop-2-yl]hydroxylamine, a new representative of the series of α-hydroxylamino oximes, was synthesized. Based on this compounds, 3-imidazoline 3-oxide and 2-imidazoline 3-oxide derivatives, were obtained, and some of their chemical properties were investigated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 131–136, January, 1997.     

X-ray emission and X-ray photoelectron studies of the electronic structure of the polymeric cubane cluster compounds Mo4S4Cl4, GaMo4S8, and GaMo4S4Te4

X-ray emission and X-ray photoelectron spectroscopy was used to study the electronic structures of the polymeric cubane cluster compounds Mo₄S₄Cl₄, GaMo₄S₈, and GaMo₄S₄Te₄. It is revealed that the ligand orbitals make significant contributions to the highest occupied molecular orbitals (M−M bonds). Substitution in the series Cl−S−Te increases the covalence of the metal—bridging ligand bonds. The experimental spectra allowed the construction of a qualitative scheme of the electronic structure of Mo₄S₄Cl₄. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 6, pp. 1038–1045, November–December, 1995. Translated by I. Izvekova     

The first ionization potentials and conjugation in benzene derivatives containing organosilicon, organogermanium, organotin, and organolead substituents

The inductive and resonance effects of silicon-, germanium-, tin-, and lead-containing and some organic substituents on the HOMO energies (E _HOMO) for 43 monosubstituted andp-disubstituted benzene derivatives were analyzed in the Koopmans approximation. A linear dependence between the perturbation energy δE and the resonanceσ _R ⁺ parameters of the substituents was established. The Koopmans approximation is a rough approximation for the compounds studied, since to provide for its rigorous fulfilment, the δE values must depend on the σ _R ⁰ parameters of the substituents. The principal regularities of increasing the σ,π-conjugation between the organoelement substituents and the π-system caused by a positive charge on the benzene ring were established. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 70–75, January 1997.     

Synthesis of derivatives of the new heterocyclic system pyrimido[5′,4′:5,6]pyrido[3,2-b]indole

Derivatives of the new heterocyclic system 1,11-dihydro-4H-pyrimido[5′,4′: 5,6]pyrido[3,2-b]indol-4-one were synthesized by the reactions of 2-(2-cyanoprop-2-enylidene)indolin-3-ones, bearing the primary and secondary amino groups in position 3 of the side chain, with DMF diethyl acetal. A scheme of formation of the synthesized compounds was proposed and confirmed. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1529–1535, August, 2007.