Generation of hexahydroazulenes

(Z)-Cyclodec-1-en-6-yne (3) generates three conjugated hexahydroazulenes 3→1k→1c, 1? under FVP conditions, whereas flash vacuum pyrolysis (FVP) of cyclodecyne (2) leads to 1,2,9-decatriene (9). We attribute the different thermal behavior of 2 (ring opening) and 3 (ring closure) to different transannular interactions. Altogether 22 constitutional isomers of hexahydroazulene should exist; three new isomers (1k, 1?, and 1m) are presented here, ten were described earlier, but the reinvestigation of the dehydration route of bicyclic alcohol 11 showed that one of the ten structures has to be revised.     

Generation of carbon-cage polyhedra

The problem of the generation of polyhedra with degree-3 vertices, and faces each of which is pentagonal or hexagonal, is addressed in order to characterize carbon in order to characterize clusters of ca. 30 or more atoms. Following Eulerian type arguments such polyhedra are subcategorized in terms of numbers of different types of local structures. An algorithm to generate such polyhedra is developed, and its computer implementation is described. Results for smaller than 80-vertex cages of subcategories anticipated to be more chemically relevant are reported. The singular position of the truncated-icosahedron (buckminsterfullerene) structure is noted.     

Enzymatische Analyse neuer Generation

Zusammenfassung Die neue Generation der enzymatischen Analyse, beeinflußt durch den Einsatz von Mikroprozessoren, und auf der Basis von Reagentien auf Trägern, erlaubt es heute bereits mit relativ einfachen Mitteln und miniaturisierten Systemen qualitativ hochstehende Analysenergebnisse mit einem Zeitaufwand zu erzielen, der bisher nicht für möglich gehalten wurde. Die Stärke der enzymatischen Analyse, die Spezifität der als Reagentien eingesetzten Enzyme, kombiniert mit modernen Detektoren, ist rein physikalischen/chemischen Verfahren in den meisten Fällen überlegen.

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Enzymatic analysis of the new generation

Summary The new generation of enzymatic analysis (influenced by the application of microprocessors and on the basis of reagents on carriers) provides the possibility to obtain high-quality results within a period of time which has hitherto been regarded as impossible, using relatively simple means and miniaturized systems. The special feature of enzymatic analysis, the specifity of the enzymes used as reagents, combined with modern detectors, is in most cases superior to purely physical/chemical methods.

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Vortrag GDCh-Ortsverband Paderborn, 28. November 1983     

Solar Hydrogen Generation from Lignocellulose

Photocatalytic reforming of lignocellulosic biomass is an emerging approach to produce renewable H₂. This process combines photo‐oxidation of aqueous biomass with photocatalytic hydrogen evolution at ambient temperature and pressure. Biomass conversion is less energy demanding than water splitting and generates high‐purity H₂ without O₂ production. Direct photoreforming of raw, unprocessed biomass has the potential to provide affordable and clean energy from locally sourced materials and waste.     

Generation and capture of alkylchlorosilanones

Alkyltrichlorosilanes react with DMSO (molar ratio 1 : 1 0 °C) to give cyclic oligoalkylchlorosiloxanes of the general formula [R(Cl)SiO] _n (where R=Me or Et;n=3–6). With an excess of alkyltrichlorosilane (2: 1), linear oligoalkylchlorosiloxanes Cl[R(Cl)SiO] _m SiCl₂R (where R=Me or Et;m=1–5) are also formed. In the presence of hexamethyldisiloxane (molar ratio Cl₃SiR : DMSO: (Me₃Si)₂O=1:1:2, 20 °C), the reaction products are both cyclic and linear oligoalkyl(trimethylsilyloxy)siloxanes [R(Me₃SiO)SiO] _n (n=3–5) and Me₃Si[OSi(OSiMe₃)R] _m OSiMe₃ (m=1–3), respectively. The reaction of DMSO with trichloro(vinyl)silane and hexamethyldisiloxane occurs in a similar manner. A plausible scheme of formation of the final products via intermediate alkylchlorosilanones RClSi=O and alkyl(trimethylsilyloxy)silanones is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 361–364, February, 2000.     

Cross-Propagation Sum-Frequency Generation Vibrational Spectroscopy

Here we report the theory formulation and the experiment realization of sum-frequency generation vibrational spectroscopy (SFG-VS) in the cross-propagation (XP) geometry or configuration. In the XP-SFG-VS, the visible and the infrared (IR) beams in the SFG experiment are delivered to the same location on the surface from visible and IR incident planes perpendicular to each other, avoiding the requirement to have windows or optics to be transparent to both the visible and IR frequencies. Therefore, the XP geometry is applicable to study surfaces in the enclosed vacuum or high pressure chambers with far infrared (FIR) frequencies that can directly access the metal oxide and other lower frequency surface modes, with much broader selection of visible and IR transparent window materials. The potential applications include surface science, material science, fundamental catalytic sciences, as well as low temperature molecular sciences, etc.     

Generation and Trapping of Triafulvene

Substituted methylidenecyclopropanes 12a – d , being easily available from 1,1-dibromo-2-(phenylthio)-cyclopropane ( 9a ), are attractive precursors of triafulvene (2-methylidene-1-cyclopropene; 1 ). Both the sulfoxide 12b and the sulfone 12c react with an excess of alkoxides (t-BuOK and NaOMe) to give 12e and 12f , respectively, while the sulfinyl group of 12b may be replaced by the PhCH₂S substituent in the presence of PhCH₂SH/t-BuOK. These reactions (Scheme 4) may be explained by assuming 1 as a reactive intermediate, although an alternative sequence including carbene 20 (Scheme 6) is not completely ruled out. D -labelling experiments (Scheme 5) do not give conclusive evidence due to D scrambling, but deprotonation/methylation sequences show that H? C(2) of 12a – c is the most acidic proton. Final evidence for 1 results from the reaction of 12d with cyclopentadienide (Scheme 7): the reaction of 1 with cyclopentadiene produces the expected [4 + 2]-cycloaddition product 23 , while some mechanistic insight results from the sequence 12d → 24 → 25 .     

光产碱反应及其应用

光产酸剂作为光引发剂具有良好的引发效果，广泛应用于高分子领域，但使用光产酸剂会引起基材的腐蚀，而光产碱剂则无此弊病，故引起许多学者的兴趣。主要综述了光产碱剂和光产碱的类型、光化学反应机理及其应用。     

Coulometric Generation of Molecular Iodine

Coulometric generation of molecular iodine at the Pt anode in acid 0.2 M KI solutions was investigated in a cell without diaphragm. The current efficiency by iodine was studied in a wide range of anode current densities (3-100 mA cm^-2).     

Generation and characterization of phenylsulfanylcarbene

A photosensitive precursor (1) to phenylsulfanylcarbene 2 has been synthesized. Laser flash photolysis (308 nm) of 1 and chemical trapping studies of 2 are reported. [structure: see text]     

Generation and reactions of azaxylylenes

Azaxylylenes produced by flash vacuum pyrolysis of 2-aminobenzyl alcohols, dihydrobenzoxazinones and dihydrobenzoxazines undergo intramolecular cyclisation, H-shifts or Diels-Alder reactions, depending on their substituents.     

Generation of polymerosomes from double-emulsions

Diblock copolymers are known to spontaneously organize into polymer vesicles. Typically, this is achieved through the techniques of film rehydration or electroformation. We present a new method for generating polymer vesicles from double emulsions. We generate precision water-in-oil-in-water double emulsions from the breakup of concentric fluid streams; the hydrophobic fluid is a volatile mixture of organic solvent that contains dissolved diblock copolymers. We collect the double emulsions and slowly evaporate the organic solvent, which ultimately directs the self-assembly of the dissolved diblock copolymers into vesicular structures. Independent control over all three fluid streams enables precision assembly of polymer vesicles and provides for highly efficient encapsulation of active ingredients within the polymerosomes. We also use double emulsions with several internal drops to form new polymerosome structures.     

Singlet Oxygen Generation by Metallotexaphyrins

Abstract. Metallotexaphyrins have clinical applications as photo-sensitizers of photodynamic therapy (PDT). The singlet oxygen quantum yield (φ>_Δ) was determined for a series of metallotexaphyrin derivatives (Lu [III], Y [III], Cd [II], In [III] and Gd [in]) under conditions where the agents are believed to exist in monomeric form. The results show φ_Δ of metallotexaphyrins vary with the medium and the metal cation. Measurements on the Lu (III) texaphyrin led to φ_Δ= 0.38 in unbuffered 5% Tween 20 and φ_Δ= 0.58 in pH 7.4 phosphate buffer plus 1% Triton X-100 (±10%). The in vitro photodynamic efficiency calculated from φ_Δ is compared to in vivo PDT efficacy in an animal tumor model.     

Genomsequenzierer. Die dritte Generation

Although the living cell can read its genetic information from a single molecule of DNA, researchers have used vast numbers of identical copies in traditional sequencing methods. Dramatic improvements in sequencing technology only became available after the first sequencing of the human genome was finished and led to a rapid drop in costs by five orders of magnitude. Instruments of the third generation, now reaching the market, will for the first time read single molecules and reduce costs even further. The implications for medicine and society will be profound.     

Generation of genealogical spin eigenfunctions

A method is given for generating the Yamanouchi-Kotani genealogical spin eigenfunctions which requires neither storage of eigenfunctions for smaller numbers of electrons, nor summations of large order, nor explicit use of results from the theory of representations of the symmetric group. An explicit formula is given for the coefficients of expansion in terms of spin products.     

和频与差频振动光谱实验构型的分析模拟

实验构型分析是定量分析和频振动光谱的基础.变换实验构型,不仅要考虑某一振动模式信号强度的大小,还要考虑不同构型下的信号检测效率.现有的和频振动光谱实验构型分析主要考虑前者.本文探讨实验构型分析中所涉及的信号检测效率问题,模拟在共向式和频(差频)及对射式和频(差频)振动光谱实验中选取何种实验构型对采集信号光更加合理有效.利用相干光学过程能量守恒和动量守恒原理,分析了入射角及入射光频率等因素对信号出射角的影响,并模拟了信号出射角与入射角及入射光频率的关系,得到了可选的入射角组合最多、出射角随入射光频率变化最小的实验构型.结果表明,和频振动光谱采取共向式实验构型,差频振动光谱采取对射式实验构型,有利于信号采集,进而有利于用实验构型分析方法对和频(差频)振动光谱进行定量研究.     

计量合成学的产生与发展

对计量合成学的产生与发展及其研究与应用进行了综论，强调了计量化学在合成中的应用，集中在开发有机合成反应的决策及战术方面，通过试验设计对反应体系深入探索及通过自适应建模对试验条件的系统优化和通过综合评价对合成产物的全面考察，将有机反应开发为合成方法，参考文献３５篇。