Insights into the Decomposition and Polymerization of Cage Energetic Crystal Octanitrocubane under High Pressure: a DFT-D Study

Dispersion-corrected DFT calculations have been performed to study the crystal structure, initial decomposition mechanism, polymerization mechanism, electronic structure and absorption properties of the most powerful CHNO energetic compound octanitrocubane(ONC) under hydrostatic pressure of 0~200 GPa. Our results show that the lattice parameter c is sensitive to van der Waals interactions and the structure is the stiffest in the a direction. ONC decomposes by the breaking of N–O bond in nitro group at 195 GPa. At 200 GPa, ONC decomposes through the breaking of N–O bond in nitro group and polymerizes through the forming of a new C–O covalent bond between a carbon atom in the cage skeleton and one oxygen atom of nitro group in another ONC molecule. ONC becomes more and more sensitive under high pressure and transforms into a metallic phase in the pressure range of 175~200 GPa. ONC also has higher optical activity and wider absorption range under compression.     

Synthesis of a 1,2,7,8-Tetraoxa-spiro[5.5]undecane

Synthesis of a new spiro organic peroxide is described. The peroxy bonds were incorporated into the substrate framework via an acid-catalyzed ketal exchange reaction using hydrogen peroxide as the source of peroxy linkage. The hydroperoxyl groups were then bonded at the OH ends via Hg（II）-induced electrophilic additions to the C-C double bonds, giving a novel sprio structure with one peroxy bond in each of the two six-membered rings. The ester functionalities in the side chains also make it possible to conduct further structural modifications.     

Synthesis and crystal structure of β-hexanitrohexaazaisowurtzitane

A polycyclic caged compound with high strain——hexanitrohexaazaisowurtzitane (HNIW)——has been synthesized via a three-step reaction: condensation, hydrogenolysis debenzylation and nitrolysis, starting with benzylmine and glyoxal. HNIW is the most powerful high energy density compound (HEDC) ever tested. β-HNIW possesses a caged structure consisting of two five-membered rings and one six-membered ring with a nitro group attached to each of the six bridging nitrogens. The nitro group lies basically within a plane. The lengths of C--C bonds of β-HNIW range from 0.156 nm to 0.159 nm, 0.002--0.005 nm longer than the sp~3 C-C bond. The β-HNIW's crystal belongs to orthorhombic system and space group Pca2_1 with parameters: a=0.9670 (2), b=1.1616 (2), c=1.3032 (3) nm; V=1.4638(5) nm~3, Z=4; D_c=1.989 g/cm~3 and D_m=1.982 g/cm~3.     

Chiroptical properties of artemisinin and artemether investigated using time-dependent density functional theory

Chiroptical properties including electronic circular dichroism(ECD) and optical rotatory dispersion(ORD) of artemisinin and artemether have been fully studied using quantum-chemical calculation based on time-dependent density functional theory.Both theoretical ECD and ORD of these two compounds were in good match with the experimental data.ECD spectrum of artemether could be totally attributed to the peroxide group,and that of artemisinin was an overlay of contribution from δ-lactone and peroxide moieties,which leading to a positive maximum at 260 nm.Our results showed that peroxide group could produce a broad ECD band in the far-UV region originated from electron transitions of HOMO →LUMO,HOMO-1 →LUMO and HOMO-2 →LUMO in the case of artemether.This work provided a theoretical interpretation of the ECD behavior of peroxide bond.     

Preparation of the N,19-seco Norditerpenoid Alkaloids from Norditerpenoid Alkaloid Yunaconitine

The synthesis of a new N,19-Seco norditerpenoid alkaloid 7 bearing nitro group from yunaconitine 1 as the starting material through a series of steps was described.     

Infrared Spectra and Pyrolysis of Selected Molecular Models of Coal: Insight from Density Functional Calculations

Equilibrium structures and infrared spectra of four typical molecular models of coal have been studied by density functional calculations. Combining theoretical calculations on the coal models with experimental FT-IR spectra of selected low rank perhydrous coals, a plausible molecular representation for this kind of coals was proposed, and its predicted IR spectra reasonably match the experimental observation. Calculations indicate that the cleavage of the C-C bridge bond for the coal structures considered here occurs at about 540 ℃ and the C-O ether bridge bond may break under temperature ranging from 500 to 600 ℃ for the aryl-CH2-O-CH2-aryl ether bond or from 200 to 300 ℃ for the aryl-CH2-O-aryl ether bond, showing remarkable effect of the local structural environment. The coal model containing the carboxyl group may release CO2 at about 300 ℃ through the decarboxylation with a barrier of 69 kcal/mol.     

The thiamine-dependent enzyme of the vitamin K biosynthesis catalyzes reductive C-N bond ligation between nitroarenes and α-ketoacids

The thiamine-dependent enzyme(1R,2S,5S,6S)-2-succinyl-5-enolpyruvyl-6-hydroxyl-3-cyclohexene-1-carboxylate(SEPHCHC) synthase,also known as MenD,catalyzes a Stetter-like reaction in the biosynthesis of vitamin K.It is found to catalyze a novel reductive C N bond ligation reaction between nitroarenes and-ketoacids to form N-hydroxamates.This reaction likely proceeds through an enzyme-mediated,slow two-electron reduction of the nitroalkanes to form a nitroso intermediate,which serves as the electrophilic acceptor of the ketoacid-derived acyl anion.The involvement of the nitroso intermediate is supported by the fact that similar N-hydroxamates are readily formed at a much higher rate when nitroso compounds replace the nitro substrates in the chemoenzymatic reactions.These results demonstrate that the thiamine-dependent enzyme is able to catalyze novel,nonnative reactions that may find new chemoenzymatic applications.     

Regioselective B—H/C—H Bond Activation at Azo-Substituted Carboranes Induced by Half-Sandwich Iridium(III)Complex

We report herein a practical approach for regio-selective B—H/C—H bond activation at azo-substituted carboranes. The reaction proceeded through Iridium(III)-induced selective B—H/C—H bond activations based on an azo directing group. Through this strategy, a series of mononuclear, trinuclear and tetranuclear cyclometalated iridium complexes containing Cp*Ir—B or Cp*Ir—C bonds were successfully isolated in a high yield. In this work, efficient routes are developed through one-pot reactions to prepare polynuclear organometallic complexes.     

The Covalent Binding of Photosensitive Dyes to Monocrystalline Silicon Surface and Their Spectral Response

A chemical method is proposed to bond photo-sensitive dyes directly to the surface of polished monocrystalline silicon. A methincyanine dye and a trimethincyanine dye have been bonded covalently onto silicon surface through Si—N bond, which are characterized by XPS technique and laser Raman spectra. Photovoltaic effect has been observed with the In/dye/n-Si sandwich devices composed of the dye-bonded n-Si wafers. Significant spectral response shows the characteristic absorptance maxima of the bonded dyes.     

Transformations of N-arylpropiolamides to indoline-2,3-diones and acids via C≡C triple bond oxidative cleavage and C(sp^2)–H functionalization

A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described,which is promoted by a cooperative action of catalytic CuBr2,2,2,6,6-tetramethyl-1-piperidinyloxy(TEMPO)and O2.The method provides a practical tool for transformations of alkynes by means of a C–H functionalization strategy,which enables the formation of one C–C bond and multiple C–O bonds in a single reaction with high substrates compatibility and excellent functional group tolerance.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。