Synthese und Konstitution von HIS2O8

Synthesis and Constitution of HIS₂O₈ Novel HIS₂O₈ has been obtained by reacting iodic acid and oleum at 210 °C. According to the results of a X-ray structure determination (monoclinic, P2₁/c, a = 1172.0(2), b = 625.7(2), c = 956.0(2) pm, β = 106.50(2), Z = 4, 1083 reflections, R₁ = 0.037, wR² = 0.103) iodine is connecting a sulfate and a hydrogensulfate group, thus forming IO₂ bridges. This can be regarded as a condensation of hypothetical iodic acid (III), HIO₂, with sulfuric acid.     

Contribution to chemistry of the 6-methyl-8-ergolene-8-carbonic acid

It is shown that several chemical transformations, well known from the chemistry of lysergic acid, can be applied to derivatives of 6-methyl-8-ergolene. Under suitable conditions no appreciable rearrangement to the corresponding 9-ergolene derivatives (lysergic acid derivatives) is observed. These transformations include preparation of amides via the acyl-chloride, alkylation of the free acid and of its amides in position 1, bromination in position 2 and reduction of the aminocarbonyl group by means of LiAlH₄. Some investigations about the stability of 8-ergolene derivatives with regard to rearrangement to 9-ergolenes are reported.     

[Pd8(CH3COO)8(NO)8]: solution from X‐ray powder diffraction data

The water‐insoluble title compound, octakis(μ‐acetato‐κ²O:O)­octakis(μ‐nitro­so‐κ²N:O)­octapalladium(II), [Pd₈(CH₃COO)₈(NO)₈], was precipitated as a yellow powder from a solution of palladium nitrate in nitric acid by adding acetic acid. Ab initio crystal structure determination was carried out using X‐ray powder diffraction techniques. Patterson and Fourier syntheses were used for atom locations, and the Rietveld technique was used for the final structure refinement. The crystal structure is of a molecular type. The skeleton of the [Pd₈(CH₃COO)₈(NO)₈] mol­ecule is con­structed as a tetragonal prism with Pd atoms at the vertices. The eight NO⁻ groups are in bridging positions along the horizontal edges of the prism. The N and O atoms of each nitro­so group coordinate two different Pd atoms. The vertical edges present Pd⋯Pd contacts with a short distance of 2.865 (1) Å. These Pd atoms are bridged by a pair of acetate groups in a cis orientation with respect to each other. The complex has crystallographically imposed 4/m symmetry; all C atoms of the acetate groups are on mirror planes. The unique Pd atom lies in a general position and has square‐planar coordination, consisting of three O and one N atom.     

Monosubstitution von Octa(hydridosilasesquioxan) H8Si8O12 zu R′H7Si8O12 mittels Hydrosilylierung Kurzmitteilung

Monosubstitution of Octa(hydridosilasesquioxane) H₈Si₈O₁₂ to R′H₇Si₈O₁₂ by Hydrosilylation Hydrosilylation of hex-1-ene and of styrene by octa(hydridosilasesquioxanes) catalyzed by hexachloroplatinic acid leads to the first monosubstituted octasilasesquioxane R′H₇Si₈O₁₂ molecules.     

Single step conversion of UO2 and U3U8 into uranyl sulphate solution

A direct and simple method for the conversion of UO₂ and U₃O₈ powder into uranyl sulphate solution is described, eliminating many tedious chemical steps. UO₂ and U₃O₈ are not soluble in concentrated or dilute sulphuric acid, as uranium in lower oxidation state does not react with sulphuric acid. However, nitric acid oxidizes uranium from lower valency to higher valency state, i.e., tetravalent to the hexavalent uranyl ion in solution. Sufficient amount of sulphuric acid present in the reaction mixture makes it possible for uranyl ions, formed by oxidation of nitric acid, to react with sulphuric acid forming uranyl sulphate.     

Aspects of tautomerism. 8. Solvolysis of some pseudo and normal acid chlorides

Pseudo acid chlorides derived from levulinic acid ando-benzoyl-benzoic acid, solvolyse in aqueous acetone, aqueous dioxane and aqueous dimethylformamide by aS _Nl process. Their reaction pattern is distinct from that of typical normal acid chlorides, viz.,p-benzoylbenzoyl chloride and fluorene-9-one-1-carboxylic acid chloride, which solvolyse by aS _N2 pathway. No evidence for tautomerism could be obtained either between the normal and pseudo forms of the acid chlorides or the derived ion pairs.     

Spectroscopically tracing the reactions of octahydridosilsesquioxane (H8Si8O12) with organic molecules

This article studies the reactions and mechanisms of H₈Si₈O₁₂ (T₈H₈) molecules with n-propanol, acetone, allyl alcohol, n-butylamine, allylamine, acetic acid, and 1-octene in air, at room temperature, and without catalysts. The reaction between T₈H₈ and n-propanol involves both the highly polarized Si O and Si H bonds and results in cage breakage and forming Q⁴ and Q³ structures with  OC₃H₇ in the reaction product. T₈H₈ also reacts with acetone, and the resultant product possesses Si OCH(CH₃)₂. Allyl alcohol is less reactive to cause T₈H₈ decomposition, and the resultant product contains Si OCH₂CHCH₂ and Si OCH₂(CH₂)₃CHCH₂. However, it is found that basically T₈H₈ does not react with acetic acid and 1-octene. In the reactions of T₈H₈ with n-butylamine and allylamine, the resultant products contain Si NH(CH₂)₃CH₃ and Si NHCH₂CHCH₂, respectively. For the reaction with T₈H₈, allylamine is less active than n-butylamine. Possible mechanisms for the T₈H₈ reactions are discussed.     

均苯四甲酸与八羟基喹啉的氢键层状结构

8-Hydroxyquinoline （8-q） salt of pyromellitic acid （benzene-1,2,4,5-tetracarboxylic acid, H4bta） forms robust lamellar structure where [H2bta]^2- anions build up sheets through strong hydrogen bonds in two dimensions and [H-8-q]^＋ cations act as pillars to afford an extended three dimensional network.     

Synthesis of 7-oxo-8-aza-10a-homoprost-13-enoic acid

The synthesis of a prostaglandin E₁ analog, 7-oxo-8-aza-10a-homoprost-13-enoic acid, is reported.     

Intramolecular Aminocyanation of Alkenes by NCN Bond Cleavage

A metal‐free, Lewis acid promoted intramolecular aminocyanation of alkenes was developed. B(C₆F₅)₃ activates N‐sulfonyl cyanamides, thus leading to a formal cleavage of the N? CN bonds in conjunction with vicinal addition of sulfonamide and nitrile groups across an alkene. This method enables atom‐economical access to indolines and tetrahydroquinolines in excellent yields, and provides a complementary strategy for regioselective alkene difunctionalizations with sulfonamide and nitrile groups. Labeling experiments with ¹³C suggest a fully intramolecular cyclization pattern due to the lack of label scrambling in double crossover experiments. Catalysis with Lewis acid is realized and the reaction can be conducted under air.     

Brønsted Acid Mediated Novel Rearrangements of Diarylvinylidenecyclopropanes and Mechanistic Investigations Based on DFT Calculations

Diarylvinylidenecyclopropanes undergo a novel rearrangement in the presence of the Brønsted acid Tf₂NH (Tf: trifluoromethanesulfonyl) to give the corresponding naphthalene derivatives in good to high yields upon heating, whereas in the presence of the Brønsted acid toluene‐4‐sulfonic acid (p‐TSA), the corresponding triene derivatives are afforded in moderate to good yields under mild conditions. Corresponding mechanistic studies on the basis of density functional theory (DFT) with the Gaussian03 program by using the B3LYP method have revealed that the pK_a value of the Brønsted acid, as well as the entropy and solvent effects, plays a significant role in this reaction; these factors can discriminate the differences in the reactivity and regioselectivity among the Brønsted acids used in this reaction. In the presence of Lewis acid Sn(OTf)₂, a butatrienecyclopane can produce the corresponding ring‐opened products in moderate yields.     

A quantum chemical study of silsesquioxanes: H8Si8O12, Me8Si8O12, H@Me8Si8O12, He@Me8Si8O 12 + , and He@Me8Si8O12

Quantum chemical PBE0 and B3LYP/cc-pVTZ, PBE0, B3LYP, RHF and MP2/6-31G(d,p) methods are employed to calculate the structural parameters of octa(silsesquioxane) H₈Si₈O₁₂ and octa(methylsilsesquioxane) Me₈Si₈O₁₂. These molecules and complexes H@Me₈Si₈O₁₂, He@Me₈Si₈O ₁₂ ⁺ , and He@Me₈Si₈O₁₂ have highly symmetric (O _h ) equilibrium configurations. With the use of the PBE0 method and a cc-pVTZ multicenter basis set common for the complex and its components coincidence is achieved between the calculated polarizability of a free He atom and the experimental value of 0.21 ų and the polarizability depression of 0.17 ų was found for He@Me₈Si₈O₁₂. In order to avoid the false conclusion about molecular symmetry the calculations of the structure of silsesquioxanes must be performed with sufficiently high accuracy (Int = ultrafine and Opt = tight in the use of the GAUSSIAN program).     

不同方法合成的沸石咪唑酯骨架结构材料(ZIF-8)的表征和催化性能

以二甲基咪唑为有机连接体和以Zn(OH)2或Zn(NO3)2·6H2O为Zn源,在甲醇与氨水的混合溶液、甲醇和DMF 3种不同的合成体系中合成了沸石咪唑酯骨架结构材料ZIF-8(分别记为ZIF-8(NH4OH)、ZIF-8(MeOH)和ZIF-8(DMF),并采用XRD、FTIR、N2吸附、SEM、TPD及Knoevenagel缩合反应等手段对所合成材料进行了表征。结果表明,采用这3种不同的合成方法均可成功制备出ZIF-8,所合成的ZIF-8的形貌基本一致,但其晶粒大小和酸碱性能有较大区别,同ZIF-8(NH4OH)和ZIF-8(DMF)相比,ZIF-8(MeOH)晶粒分布集中、平均粒径较小且具有较大的外比表面积和较多的酸碱位。不同方法合成的ZIF-8在苯甲醛和丙二腈的Knoevenagel缩合反应中的催化性能有很大差异,ZIF-8(MeOH)催化活性明显高于ZIF-8(DMF)和ZIF-8(NH4OH),其较高的催化活性,同其较大的外比表面积和酸碱性能密切相关。     

不同方法合成的沸石咪唑酯骨架结构材料(ZIF-8)的表征和催化性能

以二甲基咪唑为有机连接体和以Zn(OH)₂或Zn(NO₃)₂·6H₂O为Zn源,在甲醇与氨水的混合溶液、甲醇和DMF₃种不同的合成体系中合成了沸石咪唑酯骨架结构材料ZIF-8(分别记为ZIF-8(NH₄OH)、ZIF-8(MeOH)和ZIF-8(DMF),并采用XRD、FTIR、N₂吸附、SEM、TPD及Knoevenagel缩合反应等手段对所合成材料进行了表征。结果表明,采用这3种不同的合成方法均可成功制备出ZIF-8,所合成的ZIF-8的形貌基本一致,但其晶粒大小和酸碱性能有较大区别,同ZIF-8(NH₄OH)和ZIF-8(DMF)相比,ZIF-8(MeOH)晶粒分布集中、平均粒径较小且具有较大的外比表面积和较多的酸碱位。不同方法合成的ZIF-8在苯甲醛和丙二腈的Knoevenagel缩合反应中的催化性能有很大差异,ZIF-8(MeOH)催化活性明显高于ZIF-8(DMF)和ZIF-8(NH₄OH),其较高的催化活性,同其较大的外比表面积和酸碱性能密切相关。     

Hematoside with 8-O-methyl-N-glycolylneuraminic acid from the starfishLinckia laevigata

A ganglioside was isolated from the starfishLinckia laevigata, and its structure was elucidated by chemical methods, mass spectrometry, and enzymatic hydrolysis with neuraminidase. The ganglioside is a hematoside containing 8-O-methyl-N-glycolylneuraminic acid, 8-O-Me-Neu5Gc-α2→3-Gal-β1→4-Glc-β1→1-Cer. The lipid part of the ganglioside consists of unsubstituted fatty acids (the major component is palmitic acid) and C_18∶1-iso-sphingenine.     

Action du chlorure de nitrosyle sur le trichloréthylène et sur le tétrachloréthylène

Nitrosyl chloride is only chlorinating in darkness and above 100°. In the sun light and at room temperature it reacts as a chlorinating, nitrosating, nitrating and oxidizing agent. With trichlorethylene in fact pentachlorethane 1,1,1,2-tetrachloro-2-nitrosoethane, 1,1,1,2-tetrachloro-2-nitroethane, dichloracetic acid and a compound of empirical formula C₄H₂Cl₅NO₂ are obtained. Tetrachloroethylene carried to hexachlorethane, pentachloronitrosoethane and tetrachloro-2-(pentachlorethyl)-1,2-oxazetidine. Introduced nitrosyl chloride provided nitrogen monoxide prouved by gaz chromatography. This monoxide reacted afterwards to give nitrogen which is the single nitrogenous gazeous compound. Carbondioxide is a minor component of the gaz.     

The Strongest Brønsted Acid: Protonation of Alkanes by H(CHB11F11) at Room Temperature

What is the strongest acid? Can a simple Brønsted acid be prepared that can protonate an alkane at room temperature? Can that acid be free of the complicating effects of added Lewis acids that are typical of common, difficult‐to‐handle superacid mixtures? The carborane superacid H(CHB₁₁F₁₁) is that acid. It is an extremely moisture‐sensitive solid, prepared by treatment of anhydrous HCl with [Et₃Si? H? SiEt₃][CHB₁₁F₁₁]. It adds H₂O to form [H₃O][CHB₁₁F₁₁] and benzene to form the benzenium ion salt [C₆H₇][CHB₁₁F₁₁]. It reacts with butane to form a crystalline tBu⁺ salt and with n‐hexane to form an isolable hexyl carbocation salt. Carbocations, which are thus no longer transient intermediates, react with NaH either by hydride addition to re‐form an alkane or by deprotonation to form an alkene and H₂. By protonating alkanes at room temperature, the reactivity of H(CHB₁₁F₁₁) opens up new opportunities for the easier study of acid‐catalyzed hydrocarbon reforming.     

Straightforward Synthesis of the Brønsted Acid hfipOSO3H and its Application for the Synthesis of Protic Ionic Liquids

The easily accessible hexafluoroisopropoxysulfuric acid ( 1 , hfipOSO₃H ; hfip=C(H)(CF₃)₂) was synthesized by the reaction of hexafluoroisopropanol and chlorosulfonic acid on the kilogram scale and isolated in 98 % yield. The calculated gas‐phase acidity (GA) value of 1 is 58 kJ mol^?1 lower in ΔG° than that of sulfuric acid (GA value determined by a CCSD(T)‐MP2 compound method). Considering the gas‐phase dissociation constant as a measure for the intrinsic molecular acid strength, a hfipOSO₃H molecule is more than ten orders of magnitude more acidic than a H₂SO₄ molecule. The acid is a liquid at room temperature, distillable at reduced pressure, stable for more than one year in a closed vessel, reactive towards common solvents, and decomposes above 180 °C. It is a versatile compound for further applications, such as the synthesis of ammonium‐ and imidazolium‐based air‐ and moisture‐stable protic ionic liquids (pILs). Among the six synthesized ionic compounds, five are pILs with melting points below 100 °C and three of them are liquids at nearly room temperature. The conductivities and viscosities of two representative ILs were investigated in terms of Walden plots, and the pILs were found to be little associated ILs, comparable to conventional aprotic ILs.     

Zur theorie der α-ketosa¨uren: Mechanismus der enolisierung einiger brenztraubensa¨ureamide

The mechanism of enolisation of pyruvamide is discussed by the influence of substituents on the kinetic CH₃-acidity, by general base-catalysis of enolisation, by the enthalpy and entropy of activation and primary kinetic and kinetic solvent deuterium isotope effects respectively. A Bro¨nsted coefficient β = 0·71 has been obtained in the general base catalysis of pyruvdiethylamide enolisation. The effect of car☐ylsubstituents on the kinetic CH₃-acidity is produced not only by an inductive mechanism. The importance of solvent structure is demonstrated by a strong negative entropy of activation for the H₂O-catalysed reaction. In the H₂O-catalysed enolisation of pyruvdiethylamide a large kinetic deuterium solvent isotope effect k_o^H₂O/k_o^D₂O = 2·39) was obtained at 25°C. In contrast, when hydroxid is the catalyst, the primary kinetic deuterium isotope effect is unusually low (k_H/k_D = 3·5). Thus, in comparison to other keto compounds, a different mechanism of enolisation for the pyruvic acid derivatives must be postulated. Some aspects of this mechanism are discussed in the paper.     

Synthesis of 8-aza-15-hydroxy-7-oxo-12S-13E-prostenoic acids

The synthesis of a prostaglandin E₁ analog, 8-aza-15-hydroxy-7-oxo-12S-13E-prostenoic acid, is reported.