Co/Rhheterobimetallic nanoparticles were prepared from cobalt-rhodium carbonyl clusters [Co2Rh2(CO)12 and Co3Rh(CO)12] and immobilized on charcoal. HR-TEM revealed that the size of the heterobimetallic nanoparticles was ca. 2 nm and ICP-AES analysis showed a 2 : 2 and a 3 : 1 cobalt-rhodium stoichiometry (Co2Rh2 and Co3Rh1) in the heterobimetallic nanoparticles. The Co/Rhheterobimetallic nanoparticles
Studies on the Pauson–Khand reaction of alkynyl sulfoxides. Unexpectedly easy racemization of their dicobalt hexacarbonyl complexes
作者:Elvira Montenegro、Albert Moyano、Miquel A Pericàs、Antoni Riera、Angel Alvarez-Larena、Joan-F Piniella
DOI:10.1016/s0957-4166(99)00032-4
日期:1999.2
afford 1,3-rearranged enantiomerically enriched α-butyl and α-phenyl enones. The absolute configuration of the Pauson–Khand adducts was determined by X-ray diffraction. The decreased enantiomeric excess of the final products uncovered an unprecedented low temperature racemization of the hexacarbonyldicobalt complexes of alkynyl sulfoxides.
The cobalt cluster compound Co4(CO)12 has been used as a catalyst precursor in the inter- and intramolecular Pauson-Khand reaction at 150 °C under 10 atmospheres of CO.
钴簇化合物 Co4(CO)12 已被用作催化剂前体,在 10 个大气压的 CO 条件下于 150 °C 进行分子间和分子内保森-汉德反应。
Bis(cyclopentadienyl)tetracarbonyldimolybdenum-alkyne complexes mediated [2 + 2 + 1] cycloaddition: the formation of 3-substituted cyclopentenone derivatives
作者:Chisato Mukai、Masahiko Uchiyama、Miyoji Hanaoka
DOI:10.1039/c39920001014
日期:——
On heating, bis(cyclopentadienyl)tetracarbonyldimolybdenum-alkyne complexes undergo a [2 + 2 + 1] cycloaddition with norbornadiene or norbornene to afford the corresponding-3 substituted cyclopentenone derivatives, which could heardly be obtained in the cobalt-complexed alkyne-mediated Pauson-Khand reaction.
[RuCl2(CO)3]2/Et3N and (eta 3-C3H5)RuBr(CO)3/Et3N are highly effective catalyst systems for carbonylative cyclization of allylic carbonates with alkenes to give the corresponding cyclopentenones in high yields. For example, treatment of allyl methyl carbonate (1a) with 2-norbornene (2a) in the presence of a catalytic amount of [RuCl2(CO)3]2 (2.5 mol %) and Et3N (10 mol %) at 120 degrees C for 5 h under