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Cyclopentadienyl Ligand (cyclopentadienyl + ligand)

Distribution by Scientific Domains
Chemistry100%
Distribution within Chemistry
Organic Chemistry60%
General & Introductory Chemistry40%

Selected Abstracts

ChemInform Abstract: 1,2-Azaborolyls, Isoelectronic Analogues of the Ubiquitous Cyclopentadienyl Ligand: Synthesis of B-Heteroatom-Substituted 1,2-Azaborolyl Complexes and an Assessment of Their Electronic Features.

CHEMINFORM, Issue 25 2002
Shih-Yuan Liu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Chiral Ruthenium,Allenylidene Complexes That Bear a Fullerene Cyclopentadienyl Ligand: Synthesis, Characterization, and Remote Chirality Transfer

CHEMISTRY - AN ASIAN JOURNAL, Issue 3 2007
Yu-Wu Zhong Dr.
Abstract Ruthenium complexes that bear both a fullerene and an allenylidene ligand, [Ru(C60Me5)((R)-prophos)=CCCR1R2]PF6 (prophos=1,2-bis(diphenylphosphanyl)propane), were prepared by the reaction of [Ru(C60Me5)Cl((R)-prophos)] and a propargyl alcohol in better than 90,% yields, and characterized by 1H, 13C, and 31P,NMR, IR, and UV/Vis/NIR spectroscopy and MS. Cyclic voltammograms of these complexes showed one reversible or irreversible reduction wave due to the allenylidene part, and two reversible reduction waves due to the fullerene core. Nucleophilic addition of RMgBr or RLi proceeded regioselectively at the distal carbon atom of the allenylidene array. The reaction took place with a 60:40,95:5 level of diastereoselectivity with respect to the original chirality in the (R)-prophos ligand, which is located six atoms away from the electrophilic carbon center. [source]

The First Anionic Thia-Fries Rearrangements at Ferrocene: Ready Access to Trifluoromethylsulfonyl-Substituted Hydroxyferrocenes and an Extremely High Interannular Stereoinduction between Cyclopentadienyl Ligands

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 8 2010
Georg Werner
Abstract Attempts originally directed towards the generation of ferrocyne (1,2-dehydroferrocene, 4) and ferrocenediyne (1,2,1,,2,-tetradehydroferrocene, 5) by triflate elimination from the respective ferrocenyl triflates led to the discovery of the first anionic thia-Fries rearrangements at a five-membered ring. These reactions take place with remarkable efficiency under very mild reaction conditions and yield the respective trifluoromethylsulfonyl-substituted ferrocenols. Most remarkably, the reaction starting from 1,1,-ferrocenediyl ditriflate (9) adopts an extremely high interannular stereoinduction in that exclusively the meso rearrangement product, meso -2,2,-bis(trifluoromethylsulfonyl)-1,1,-ferrocenediol (16), is formed, the corresponding racemic product 17 is not observed. It is shown that the second anionic thia-Fries rearrangement proceeds at a much larger rate than the first one. The stereochemistry and the high rate of this reaction are explained on the basis of electronic as well as steric considerations. The redox behavior of some of the unprecedented ferrocene derivatives has been characterized by cyclovoltammetry. [source]

Iron-Catalyzed Oppenauer-Type Oxidation of Alcohols

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2010
Michael
Abstract A (hydroxycyclopentadienyl)iron dicarbonyl hydride catalyzes the Oppenauer-type oxidation of alcohols with acetone as the hydrogen acceptor. Many functional groups are tolerant to the oxidation conditions. The same complex also catalyzes the dehydrogenation of diols to lactones. A mechanism involving the formation of iron-alcohol complexes and their rapid ligand exchange with free alcohols is proposed. The trimethylsilyl groups on the cyclopentadienyl ligand of the catalyst play a critical role in stabilizing the iron hydride and increasing the catalyst lifetime. [source]

Ytterbocenes as One- and Two-Electron Reductants in their Reactions with Diazadienes: YbIII Mixed-Ligand Bent-Sandwich Complexes Containing a Dianion of Diazabutadiene

CHEMISTRY - A EUROPEAN JOURNAL, Issue 17 2007
Alexander
Abstract Ytterbocene [Yb(C5MeH4)2(thf)2] reacts with diazabutadiene 2,6- iPr2C6H3NCHCHNC6H3iPr2 -2,6 (DAD) as a one-electron reductant to afford a bis(cyclopentadienyl) YbIII derivative containing a DAD radical anion [Yb(C5MeH4)2(dad,.)]. However, ytterbocenes [YbCp*2(thf)2] (Cp*=C5Me5, C5Me4H) coordinated by sterically demanding cyclopentadienyl ligands act as two-electron reductants in their reactions with DAD. These reactions occur by abstraction of one Cp* ring and result in the formation of novel YbIII mixed-ligand bent-sandwich complexes, [YbCp*(dad)(thf)], in which the dianion of DAD has an uncommon terminal ,4 -coordination to the ytterbium atom. The variable-temperature magnetic measurements of complex [Yb(C5Me5)(dad)(thf)] suggest the existence of redox tautomerism for this compound. [source]