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Kim, Min,Lee, Jinwoo,Lee, Hee-Yoon,Chang, Sukbok WILEY-VCH Verlag 2009 Advanced synthesis & catalysis Vol.351 No.11
<P>It was found that the catalytic activity of rhodium complexes was highly sensitive to the type of N-heterocyclic carbene (NHC) ligands in the conversion of aldoximes to amides. Among those species examined, the (cyclooctadiene)rhodium chloride-carbene complex Rh(cod)(IMes)Cl exhibited the highest reactivity when it was employed in combination with a Brønsted acid, thus allowing mild reaction conditions. A significant rate acceleration effect resulting from the addition of nitrile additives was also observed. With the new protocol, the substrate scope of aldoximes has been widely expanded to include sterically congested and electronically varied derivatives. On the basis of detailed mechanistic studies, it is proposed that the reaction proceeds mainly via intramolecular electrophilic addition of aldoxime to rhodium-bound nitrile, which is different from the generally postulated two-step route: dehydration of aldoxime to nitrile followed by hydration of the latter intermediate.</P> <B>Graphic Abstract</B> <P> <img src='wiley_img_2010/16154150-2009-351-11-12-ADSC200900251-content.gif' alt='wiley_img_2010/16154150-2009-351-11-12-ADSC200900251-content'> </P>
WILEY-VCH Verlag 2009 EUROPEAN JOURNAL OF ORGANIC CHEMISTRY Vol.2009 No.16
<P>Tandem transformations represent one of the most efficient methods for the synthesis of complex molecules from readily available starting materials, as evidenced by the intense research activity and the plethora of literature published in this area. This review highlights recent developments of rhodium(I)-catalyzed tandem transformations with organoboron compounds involving the formation of multiple carbon–carbon bonds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)</P> <B>Graphic Abstract</B> <P>This review provides an overview of recent developments of rhodium(I)-catalyzed tandem transformations with organoborons involving the formation of multiple carbon–carbon bonds. These processes are powerful and straightforward methods for the synthesis of complex molecules including both acyclic and cyclic compounds. <img src='wiley_img/1434193X-2009-2009-16-EJOC200900001-fig000.gif' alt='wiley_img/1434193X-2009-2009-16-EJOC200900001-fig000'> </P>
Rhodium이 분산된 석탄 지지체 촉매를 이용한 탄화수소 개질
유지호 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
석탄은 구조 내 carboxyl group의 이온교환에 의해 metal complex를 형성할 수 있다. 본 연구에서는 다양한 등급의 석탄을 촉매 지지체로 이용하여 Rh 금속을 이온교환을 통해 석탄에 분산하였다. 석탄 지지체는 기존 alumina 대비 여러 장점을 갖는다. 석탄의 aromatic 성분은 탄화수소의 촉매 접촉 시간을 늘려 활성의 증가를 나타낼 수 있으며, coke의 선택적 흡착에 의해 coking에 의한 비활성화를 줄일 수 있다. 석탄은 담지된 금속에 대해 환원제로 작용하여 반응 전 촉매의 pre-reduction이 필요 없고 사용 후 촉매에서 유가 금속의 회수가 용이하다. 또한 경제성이 뛰어나며 석탄 성분의 다양성에 의해 촉매 품질의 tailoring이 가능하다. Rhodium은 석탄으로 incipient wetness impregnation에 의한 분산 시 담지량에 무관하게 10 nm 이하 크기로 고르게 분산되었다. 5 wt.% 이하의 담지에 의해서도 DME 등의 탄화수소 개질에 매우 우수한 활성을 보이며 기타 금속과는 다른 생성가스 조성을 보였다. 또한 지지체의 친유성 및 강한 금속과의 결합에 의해 coking에 대한 저항력이 강하여 우수한 지속성을 나타냈다.
Lee, Sang Ick,Park, Se Yeoun,Chung, Young Keun WILEY-VCH Verlag 2006 Advanced synthesis & catalysis Vol.348 No.16
<P>A new [Rh(cod)Cl]<SUB>2</SUB>/AgX (cod=1,5-cyclooctadiene)-catalyzed intermolecular [4+2+2] cycloaddition reaction between two enynes with one diene, and between two diynes and one diene has been developed. This is the first example of a rhodium-catalyzed trimolecular and three-component [4+2+2] cycloaddition to form eight-membered ring compounds. The yield of the reaction was highly dependent upon the counteranion and the reaction medium. The best yields were obtained when the reaction was carried out in toluene with OTf<SUP>−</SUP> anions. The regioselectivity was highly dependent upon the substrates. Relatively high regioselectivities were obtained for the cycloaddition of two enynes with one diene. In some cases, only one regioisomer was obtained. However, the regioselectivities for the cycloaddition of two diynes with one diene were rather poor. The use of a syringe pump in the slow addition of reactants slightly enhanced the regioselectivity.</P> <B>Graphic Abstract</B> <P> <img src='wiley_img/16154150-2006-348-16-17-ADSC200600321-content.gif' alt='wiley_img/16154150-2006-348-16-17-ADSC200600321-content'> </P>
Mamoru Tobisu,Ryo Nakamura,Yusuke Kita,Naoto Chatani 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.3
A rhodium-catalyzed reductive cleavage reaction of carbon-cyano bonds is developed using hydrosilane as a mild reducing agent. A wide range of nitriles, including aryl, benzyl, and β-hydrogen containing alkyl cyanides are applicable to this decyanation reaction. The method is also applicable to organic synthesis, in which benzyl cyanide is used as a benzyl anion equivalent and a cyano group functions as a removable ortho-directing group.
Tobisu, Mamoru,Nakamura, Ryo,Kita, Yusuke,Chatani, Naoto Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.3
A rhodium-catalyzed reductive cleavage reaction of carbon-cyano bonds is developed using hydrosilane as a mild reducing agent. A wide range of nitriles, including aryl, benzyl, and $\beta$-hydrogen containing alkyl cyanides are applicable to this decyanation reaction. The method is also applicable to organic synthesis, in which benzyl cyanide is used as a benzyl anion equivalent and a cyano group functions as a removable ortho-directing group.
Surface analysis of metal clips of ceramic selfligating brackets
Kyung Sook Kim,Se Jik Han,Tae-Hee Lee,Tae-Joon Park,Samjin Choi,Yoon-Goo Kang,Ki-Ho Park 대한치과교정학회 2019 대한치과교정학회지 Vol.49 No.1
Objective: The aim of this study was to analyze the surface composition, roughness, and relative friction of metal clips from various ceramic self-ligating brackets. Methods: Six kinds of brackets were examined. The control group (mC) consisted of interactive metal self-ligating brackets while the experimental group (CC, EC, MA, QK, and WA) consisted of interactive ceramic self-ligating brackets. Atomic force microscopy-lateral force microscopy and scanning electron microscopy-energy-dispersive X-ray spectroscopy were used to analyze the surface of each bracket clip. Results: All the clips in the experimental groups were coated with rhodium except for the QK clip. The results showed that the QK clip had the lowest average roughness on the outer surface, followed by the MA, EC, WA, and CC clips. However, the CC clip had the lowest average roughness on the inner surface, followed by the QK, WA, MA, and EC clips. The QK clip also had the lowest relative friction on the outer surface, followed by the MA, EC, CC, and WA clips. Likewise, the CC clip had the lowest relative friction on the inner surface, followed by the QK, WA, MA, and EC clips. Conclusions: The surface roughness and relative friction of the rhodium-coated clips were generally higher than those of the uncoated clips.
Yi Liu,Lin He,Guoqiang Yin,Guojie Wu,Yingde Cui 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.8
A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflates has been reported. This process afforded a range of biaryl compounds in excellent yields and showed high activity and broad scope.
Liu, Yi,He, Lin,Yin, Guoqiang,Wu, Guojie,Cui, Yingde Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.8
A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflates has been reported. This process afforded a range of biaryl compounds in excellent yields and showed high activity and broad scope.