نتایج جستجو برای: rhodium
تعداد نتایج: 4139 فیلتر نتایج به سال:
The rhodium-catalyzed regio- and enantioselective amination of racemic tertiary allylic trichloroacetimidates with a variety of aniline nucleophiles is a direct and efficient route to chiral α,α-disubstituted allylic N-arylamines. We describe the first dynamic kinetic asymmetric transformations of racemic tertiary allylic electrophiles with anilines utilizing a chiral diene-ligated rhodium cata...
Chiral cyclopentadienyl rhodium complexes promote highly enantioselective enol-directed C(sp(2))-H functionalization and oxidative annulation with alkynes to give spiroindenes containing all-carbon quaternary stereocenters. High selectivity between two possible directing groups, as well as control of the direction of rotation in the isomerization of an O-bound rhodium enolate into the C-bound i...
Previous studies on hydroformylation of methyl oleate with rhodium and triphenylphosphine or triphenylphosphite have led to a laboratory process for recycling the precious metal catalyst. Another catalyst recycling process has now been studied as the basis for converting commercially available oleic acid into the enol ether of methyl formylstearate. The process involves one-step esterification-...
The effect of the calcination conditions on the catalytic activity for N2O decomposition of 2.5% RhOx/CeO2 catalysts has been investigated. Ramp and flash calcinations have been studied (starting calcinations at 25 or 250/350 °C, respectively) both for cerium nitrate and ceria-impregnated rhodium nitrate decomposition. The cerium nitrate calcination ramp has neither an effect on the physico-che...
Direct metalation of C2-protected diimidozolium salts with RhCl3 or [RhCl(cod)]2 and KI afforded a series of new rhodium(III) complexes with abnormally C4-bound, cis-chelating NHC ligands. The complexes were isolated as dimetallic species containing two (μ-I)3-bridged rhodium(III) centers. In the presence of coordinating ligands such as CH3CN, PPh3, or dppe, the dimeric structure is readily cle...
A new class of tridentate phosphine ligands with the general formula [MePACHTUNGTRENNUNG{(CH2)xPPh2}3] I (x=4, 7, 11) and [MePACHTUNGTRENNUNG(CH2PPh2)3] OTf , has been synthesized and fully characterized. The linkers have been immobilized on silica with their phosphonium moieties via electrostatic interactions, and their mobility and leaching has been studied by solid-state HR-MAS (high-resolut...
Work on the synthesis of ethanol from carbon dioxide over a rhodiumselenium catalyst i s reported, and related reactions and characterisation studies are briefly reviewed. I n order to inhibit the formation of methane (complete reduction of carbon dioxide) and simultaneously activate carbon-carbon bond formation by the reaction of CH, with carbonyl derivatives, it is necessary to control the ac...
Kinetically inert metal complexes have arisen as promising alternatives to existing platinum and ruthenium chemotherapeutics. Reported herein, to our knowledge, is the first example of a substitutionally inert, Group 9 organometallic compound as a direct inhibitor of signal transducer and activator of transcription 3 (STAT3) dimerization. From a series of cyclometalated rhodium(III) and iridium...
(103)Rhodium(III) complexes derived from seven acyclic tetradentate N(2)S(2) ligands (one diaminedithiol and six diaminedithioether ligands) have been synthesized and characterized. Structural variations in the ligand include the length of carbon backbone between the coordinating atoms (222; 232; 323; 333), the presence or absence of gem-dimethyl groups α to sulfur, and the nature of the organi...
A rhodium(i) and a ruthenium(ii) complex with a caffeine derived N-heterocyclic carbene (NHC) ligand were biologically investigated as organometallic conjugates consisting of a metal center and a naturally occurring moiety. While the ruthenium(ii) complex was largely inactive, the rhodium(i) NHC complex displayed selective cytotoxicity and significant anti-metastatic and in vivo anti-vascular a...
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