نتایج جستجو برای: symmetric catalyst

تعداد نتایج: 124781  

Journal: :Organic & biomolecular chemistry 2007
Sandeep K Ginotra Vinod K Singh

A C(2)-symmetric diethyl (i)Pr-bis(oxazoline)-Cu(OAc)(2).H(2)O was found to be an efficient catalyst for catalyzing an enantioselective Henry reaction between nitromethane and various aldehydes to provide beta-hydroxy nitroalkanes with high chemical yields (up to 95%) and enantiomeric excesses (up to 97%).

Journal: :Chemical communications 2013
Bin Li Jean-Baptiste Sortais Christophe Darcel

Selective ruthenium-catalyzed reductive coupling of primary amides under hydrosilylation conditions is achieved using an one pot procedure. Using 3 equiv. of phenylsilane and [RuCl2(mesitylene)]2 (1-2 mol%) as the catalyst at 100 °C under neat conditions, secondary symmetric amines were obtained in good yields and with high chemoselectivities.

Journal: :Organic & biomolecular chemistry 2005
John S Fossey Ryosuke Matsubara Paulo Vital Shū Kobayashi

Butane-2,3-dione was activated towards nucleophilic addition of enecarbamates by a series of metal triflate complexes of a C2-symmetric diamine to give stereogenic, aldol-like, t-alcohols, a novel nickel(II) triflate complex was identified as a good catalyst for this asymmetric transformation, and an aquo nickel(II) complex was identified by XRD techniques.

2008
J. Gärtner F. den Hollander G. Maillard

The present paper provides an overview of results obtained in four recent papers by the authors. These papers address the problem of intermittency for the Parabolic Anderson Model in a time-dependent random medium, describing the evolution of a " reactant " in the presence of a " catalyst ". Three examples of catalysts are considered: (1) independent simple random walks; (2) symmetric exclusion...

Journal: :Dalton transactions 2007
Ranjan Mitra Matthew W Peters Michael J Scott

Inspired by trinuclear Zn(II) sites in enzymatic systems, a ligand system containing three preorganized (2-pyridyl)methyl piperazine moieties anchored onto a rigid C3-symmetric triphenoxymethane platform has been developed for preorganizing three zinc ions into an environment conducive to intramolecular interaction. Zinc(II) binding by this ligand has been analyzed by means of potentiometric me...

Journal: :bulletin of the iranian mathematical society 2011
a. j. frankild s. sather-wagstaff a. taylor

we investigate buchbaum and eisenbud's construction of the second symmetric power $s_r(x)$ of a chain complex $x$ of modules over a commutative ring $r$. we state and prove a number of results from the folklore of the subject for which we know of no good direct references. we also provide several explicit computations and examples. we use this construction to prove the following ...

2005
Mike Klaas

Summarization of electronic discussion fora is a unique challenge; techniques that work startlingly well on monolithic documents tend to fare poorly in this informal setting. Additionally, conventional techniques ignore much of the structures that have the potential to serve as valuable features in the summarization task. We present several novel examples of such features, including the catalys...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1390

abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی صنعتی کرمان - دانشکده علوم پایه 1392

در این پایان نامه بر مقاله ی an iterative method for the symmetric and skew symmetric solutions of a linear matrix equation axb+cyd =e نوشته ی xingping sheng و guoliang chen، مروری داشته ایم. در این مقاله دو روش تکراری برای حل معادله ی ماتریسی خطی axb+cyd=e ارائه شده است. روش اول جواب معادله را به صورت متقارن و روش دوم جواب معادله را به صورت پادمتقارن ارائه می دهد. تعدادی مثال های عددی را با...

Journal: :Dalton transactions 2010
Miriam Mba Leonard J Prins Cristiano Zonta Massimo Cametti Arto Valkonen Kari Rissanen Giulia Licini

C(3)-symmetric Ti(IV) amino triphenolate complexes efficiently catalyze, without previous activation and in excellent yields, the oxidation of sulfides at room temperature, using both CHP and the more environment friendly aqueous hydrogen peroxide as terminal oxidants, with catalyst loadings down to 0.01%. The Ti(IV) catalysts and the intermediate Ti(IV)-peroxo complexes have been characterized...

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