نتایج جستجو برای: rhodium

تعداد نتایج: 4139  

Journal: :Environmental science and pollution research international 2013
Antonio Cobelo-García

The anthropogenic inputs of Rh in the environment-together with other platinum group elements-have increased considerably during the last 20-30 years. However, thermodynamics and kinetics on the interaction of Rh with natural organic and inorganic ligands are still poorly characterized. Here, we report the time-dependent speciation of rhodium chlorides spiked to model freshwater with and withou...

Journal: :Organic & biomolecular chemistry 2015
Takanori Matsuda Shoichi Watanuki

The rhodium(I)-catalysed arylative annulation of 1,4-enynes with arylboronic acids was investigated. The reaction was found to proceed via an addition-1,4-rhodium migration-addition sequence, affording the corresponding 1,1-disubstituted 3-(arylmethylene)indanes.

Journal: :Organic letters 2014
Xueji Ma Shanfei Pan Hangxiang Wang Wanzhi Chen

Rhodium-catalyzed transannulation of 1,2,3-triazoles and ring-opening reactions of epoxides is described. A number of 3,4-dihydro-2H-1,4-oxazines are obtained in moderate yields probably involving generation of α-imino rhodium(II) carbene species.

Journal: :Organic & biomolecular chemistry 2013
Mirim Kim Jihye Park Satyasheel Sharma Sangil Han Sang Hoon Han Jong Hwan Kwak Young Hoon Jung In Su Kim

Tandem rhodium-catalyzed oxidative allylation and annulation of acetanilides with allyl acetate to afford the corresponding indoles are described. In addition, the site-selective C2 allylation, crotylation and prenylation of indoles using allylic acetates under rhodium catalysis are reported.

Journal: :Angewandte Chemie 2021

Elektrooxidative Anellierungen mittels übergangsmetallkatalysierter C-H-Aktivierung haben sich als eine transformative Strategie für den schnellen Aufbau von fünf- und sechsgliedrigen Heterocyclen erwiesen. Im Gegensatz dazu berichten wir hier über die ersten elektrochemischen metallkatalysierten [5+2]-Cycloadditionen Synthese wertvollen Benzoxepinstrukturen durch C-H/O-H-Aktivierung. Die effiz...

Introduction One of the best methods in the diagnosis and control of breast cancer is mammography. The importance of mammography is directly related to its value in the detection of breast cancer in the early stages, which leads to a more effective treatment. The purpose of this article was to calculate the X-ray spectrum in a mammography system with Monte Carlo codes, including MCNPX and MCNP5...

Journal: :Dalton transactions 2016
Xu Liu Zikuan Wang Xuefeng Fu

Catalytic intramolecular hydrofunctionalization of allylphenols to heterocyclic compounds mediated by rhodium(iii) porphyrin complexes was described. The Wacker-type intermediate β-heterocyclic alkyl rhodium complex was independently synthesized and crystallized.

1998
Jianbo Wang Bei Chen Jian Bao

The relative rates of the Rh(II)-mediated carbenoid insertion into the benzylic C-H bonds of a series of para-substituted phenyl substrates have been measured by an indirect intramolecular competition method. Three catalysts, rhodium(II) acetate, rhodium(II) trifluoroacetate, and rhodium(II) acetamide, were investigated. The effect of solvent was also studied on the reactions with rhodium(II) a...

2007
E. J. DUFEK

AND SUMMARY Procedures were developed to extract rhodium from hydroformylated vegetables oils and methyl esters. Among the numerous reagents surveyed, a q u eous hydrogen cyanide with triethanolamine (TEA) was found to be most effective. The effects of time, temperature, and concentration of reagents were stUdied. Over 98% of the solubilized rhodium was removed from crude methyl formylstearate ...

Journal: :Dalton transactions 2013
Joseph D Kistler Pedro Serna Bruce C Gates

A family of supported bimetallic samples was prepared by the reactions of Rh(C2H4)(acac) (acac = acetylacetonate) and Os3(CO)12 with MgO. The samples were characterized by infrared and extended X-ray absorption fine structure spectroscopies, before and after various treatments with hydrogen at temperatures up to 393 K. The spectra identify the following combinations of supported species: (a) [O...

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