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71.
Herein we report on the reactions of the stable LSiCl (1) and LGeCl (2) [L = PhC(NtBu)(2)] with L(1)Ge, [L(1) = CH{(C[double bond, length as m-dash]CH(2))(CMe)(2,6-iPr(2)C(6)H(3)N)(2)}] (3) to yield 1-sila-5-germylene (4) and a 1,5-bis(germylene) (5). The reactions proceed through the 1,4 nucleophilic addition of the M-Cl (M = Si or Ge) to 3 without any modification of the oxidation state although the change of the oxidation state is thermodynamically more favorable. Compounds 4 and 5 were investigated by single crystal X-ray structural analyses, multi-nuclear NMR spectroscopy, and micro-analysis. Treatment of L(1)AlMe·thf (6) with 1 resulted in the formation of the 1-sila-5-aluminium complex (7). The complex contains a Si(II) and an Al(III) atom in the molecule. All reported reactions proceed without changing the oxidation states at the metal centers.  相似文献   
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Helical tetrasubstituted alkenes ( 7 ) were obtained in a highly efficient way through a palladium‐catalyzed domino‐carbopalladation/CH‐activation reaction of propargylic alcohols 6 in good to excellent yields. Electron‐withdrawing‐ and electron‐donating substituents can be introduced onto the upper and lower aromatic rings. The substrates ( 6 ) for the domino process were synthesized by addition of the lithiated alkyne ( 20 ) to various aldehydes ( 19 ); moreover, the substrates were accessible enantioselectively (in 95 % ee) by reduction of the corresponding ketone using the Noyori procedure.  相似文献   
74.
The hydration of the binder, consisting of calcium aluminate cement (CAC) with Al2O3 >70% and with or without the additives of the FCC catalyst waste and polycarboxylate deflocculant Castament FS-20, is investigated. The methods of calorimetry, thermal analysis, XRD, electrical conductivity, SEM, as well as ultrasonic wave velocity measuring and bending strength evaluation are used. The results of the investigation show that the FCC catalyst as well as polycarboxylate deflocculant, are active additives, influencing the CAC binder??s hydration process. In the structure of the hardened binders, certain amounts of unhydrated CAC minerals, CA, and CA2, and the hydration products, such as CAH10, C2AH8 and the amorphous AH3, are found. However, in the binder with a deflocculant, there are smaller amounts of CAH10 and the amorphous AH3, though the amount of C2AH8 is higher than that in the binder without a deflocculant additive. It has been found that in the case, when the FCC catalyst and deflocculant are simultaneously used, the FCC catalyst produces a positive effect on the formation of the CAC binder??s structure, increasing its mechanical strength. The results obtained in this article allow to predict that the FCC catalyst and deflocculant simultaneously used as the additives to the CAC binder, will enable to control the hydration process of the binder.  相似文献   
75.
A fluorous organocatalyst promotes direct asymmetric aldol reactions of aromatic aldehydes with ketones in brine to afford the corresponding anti-aldol products in high yield with up to 96% ee. Fluorous organocatalyst can be readily recovered by solid phase extraction using fluorous silica gel and reused without purification.  相似文献   
76.
We present valence-to-core X-ray emission spectroscopy of Ti, TiO, and TiO2 by means of a double crystal von Hamos spectrometer based on full-cylinder highly annealed pyrolytic graphite mosaic crystals. We demonstrate that, using a double crystal configuration, an energy resolution of EE ≈ 2,700 can be achieved in a compact setup using cylindrically curved optics with a radius of curvature of 50 mm. The stated energy resolution proved to be high enough to identify and determine chemical shifts of the Kβ2,5 and Kβ″ emission lines of both oxides. The experimental results are supported by calculations with the ab initio package OCEAN and compared with literature values.  相似文献   
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The use of vinylformamide and 1,3‐divinylimidazolidin‐2‐one, bisvinylethylene‐urea (BVU), as well as of the poly(vinylformamide‐vinylamine) copolymer (PVFA‐co‐PVAm) for silica surface functionalization has been investigated. Various procedures such as grafting from, crosslinking surface polymerization, and post‐functionalization of adsorbed PVAm chains have been experimentally applied. The advantage of the different synthetic methods is discussed with regard to the resulting surface structure of the organic/inorganic hybrid materials.  相似文献   
80.
The title compounds have been prepared as analytical standards for the identification of chlorpromazine metabolites in biological materials. Unequivocal structural proof of key compounds was accomplished by using at least two unrelated syntheses for each one. Resistance of some phenothiazines to preparation via classic Smiles rearrangement is discussed. More examples are offered of halogen-induced Smiles rearrangement. A rare example of phenothiazine polymorphism is presented.  相似文献   
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