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91.
Holger Ott Christoph Matthes Dr. Arne Ringe Dr. Jörg Magull Prof. Dr. Dietmar Stalke Prof. Dr. Uwe Klingebiel Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(18):4602-4609
Borenes and boranes : Silylaminoiminoborenes, such as depicted, were isolated after treatment of halogen triels with silylaminofluoroboranes. In addition, novel aryl‐ and silyl‐substituted diaminofluoroboranes were also prepared in order to substantiate this reaction route.
92.
Xie W Herrmann C Kömpe K Haase M Schlücker S 《Journal of the American Chemical Society》2011,133(48):19302-19305
The synthesis of bifunctional Au/Pt/Au nanoraspberries for use in quantitative in situ monitoring of platinum-catalyzed reactions by surface-enhanced Raman scattering (SERS) is presented. Highly convolved SERS spectra of reaction mixtures can be decomposed into the contributions of distinct molecular species by multivariate data analysis. 相似文献
93.
94.
Asymmetric trans-bioreduction of activated alkenes by KYE1 from Kluyveromyces lactis and Yers-ER from Yersinia bercovieri, two ene-reductases from the Old Yellow Enzyme family, showed a broad substrate spectrum with a moderate to excellent degree of stereoselectivity. Both substrate- and enzyme-based stereocontrols were observed to furnish opposite stereoisomeric products. The effects of organic solvents on enzyme activity and stereoselectivity were outlined in this study, where two-phase systems hexane and toluene are shown to sustain bioreduction efficiency even at high organic solvent content. 相似文献
95.
Messner CB Hofer TS Randolf BR Rode BM 《Physical chemistry chemical physics : PCCP》2011,13(1):224-229
The four-times positively charged zirconium ion in aqueous solution was simulated, using an ab initio quantum mechanical charge field molecular dynamics approach. As no hydrolysis reaction occurred during the simulation time of 10 ps, the target of this study was the evaluation of the structure and dynamics of the monomeric hydrated zirconium(iv) ion. The ion forms three hydration shells. In the first hydration shell the ion is 8-fold coordinated with a maximum probability of the Zr-O distance at 2.25 ?. While no exchanges occurred between the first and second shell, the mean residence time of the water molecules in the second shell is 5.5 ps. A geometry of the first hydration shell in-between a bi-capped trigonal prism and a square antiprism was found and a Zr-O force constant of 188 N m(-1) was evaluated. 相似文献
96.
Tobias Schulz Dr. Sebastian Ahrens Dirk Meyer Christoph Allolio Anke Peritz Prof. Dr. Thomas Strassner 《化学:亚洲杂志》2011,6(3):863-867
Owing to numerous new applications, the interest in “task‐specific” ionic liquids increased significantly over the last decade. But, unfortunately, the imidazolium‐based ionic liquids (by far the most frequently used cations) have serious limitations when it comes to modifications of their properties. The new generation of ionic liquids, called tunable aryl–alkyl ionic liquids (TAAILs), replaces one of the two alkyl chains on the imidazolium ring with an aryl ring which allows a large degree of functionalization. Inductive, mesomeric, and steric effects as well as potentially also π π and π π+ interactions provide a wide range of possibilities to tune this new class of ILs. We investigated the influence of electron‐withdrawing and ‐donating substituents at the para‐position of the aryl ring (NO2, Cl, Br, EtO(CO), H, Me, OEt, OMe) by studying the changes in the melting points of the corresponding bromide and bis(trifluoromethanesulfonyl)imide, (N(Tf)2−), salts. In addition, we calculated (B3LYP/6‐311++G(d,p)) the different charge distributions of substituted 1‐aryl‐3‐propyl‐imidazolium cations to understand the experimentally observed effects. The results indicated that the presence of electron‐donating and ‐withdrawing groups leads to strong polarization effects in the cations. 相似文献
97.
Mohammad Aghazadeh Meshgi Alexander Pcheim Judith Baumgartner Viatcheslav V. Jouikov Christoph Marschner 《Molecules (Basel, Switzerland)》2021,26(1)
A number of mono- and dioligosilanylated silocanes were prepared. Compounds included silocanes with 1-methyl-1-tris(trimethylsilyl)silyl, 1,1-bis[tris(trimethylsilyl)silyl], and 1,1-bis[tris(trimethylsilyl)germyl] substitution pattern as well as two examples where the silocane silicon atom is part of a cyclosilane or oxacyclosilane ring. The mono-tris(trimethylsilyl)silylated compound could be converted to the respective silocanylbis(trimethylsilyl)silanides by reaction with KOtBu and in similar reactions the cyclosilanes were transformed to oligosilane-1,3-diides. However, the reaction of the 1,1-bis[tris(trimethylsilyl)silylated] silocane with two equivalents of KOtBu leads to the replacement of one tris(trimethylsilyl)silyl unit with a tert-butoxy substituent followed by silanide formation via KOtBu attack at one of the SiMe3 units of remaining tris(trimethylsilyl)silyl group. For none of the silylated silocanes, signs of hypercoordinative interaction between the nitrogen and silicon silocane atoms were detected either in the solid state. by single crystal XRD analysis, nor in solution by 29Si-NMR spectroscopy. This was further confirmed by cyclic voltammetry and a DFT study, which demonstrated that the N-Si distance in silocanes is not only dependent on the energy of a potential N-Si interaction, but also on steric factors and through-space interactions of the neighboring groups at Si and N, imposing the orientation of the pz(N) orbital relative to the N-Si-X axis. 相似文献
98.
The dinucleoside phosphate ΠdpΠd ( 4 ) was synthesized from the monomers 1-(5′-O-monomethoxytrityl - 2′ - deoxy - β - D - ribofuranosyl) - 2 (1 H) - pyridone ((MeOTr) Πd, 2 ) and 1-(5′-O-phosphoryl-3′-O-acetyl-2′-deoxy-β-D -ribofuranosyl)-(1H)-pyridone (pΠd(Ac), 3 ). Its 6.4% hyperchromicity and an analysis of the 1H-NMR. spectra indicate that the conformation and the base-base interactions in 4 are similar to those in natural pyrimidine dinucleoside phosphates. 相似文献
99.
Sodium [2-13C,2-2H3]acetate was incorporated into cytochalasin B( 1 ) by Phoma exigua and into cytochalasin D ( 2 ) by Zygosporium masonii. The 13C-NMR. and 2H-NMR. of the metabolites showed that most of the deuterium was lost except at carbon atoms which are in polyketide chain-initiating units. 相似文献
100.