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Ferrocene Derivatives (ferrocene + derivative)
Selected AbstractsElectrochemical Study of Anionic Ferrocene Derivatives Intercalated in Layered Double Hydroxides: Application to Glucose Amperometric BiosensorsELECTROANALYSIS, Issue 3-5 2009Christine Mousty Abstract Layered double hydroxides (Zn2Cr(OH)6X,nH2O LDH) containing (3-sulfopropyl)ferrocene-carboxylate (FcPSO3) and 1,1,-bis(3-sulfopropyl)ferrocene-carboxylate (Fc(PSO3)2) as interlayer anions (X) have been prepared by the co-precipitation method and characterized by PXRD, FTIR, SEM and XPS. The electrochemical behavior of these hybrid materials has been evaluated by cyclic voltammetry. A new amperometric biosensor based on the immobilization of glucose oxidase in ZnCr-FcPSO3 hybrid material was presented, the intercalated anions playing the role of mediators that shuttle electrons between the FAD centers in the enzyme and the electrode surface. The performance of the resulting biosensor for glucose determination under anaerobic conditions was evaluated by chronoamperometry at 0.5,V. The sensitivity (65,mA M,1 cm,2) determined in the concentration range 10,25,,M is higher than sensitivities reported for other glucose biosensors based on LDH host matrices. [source] Attachment of Amine- and Maleimide-Containing Ferrocene Derivatives onto Self-Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross-Linking Efficiencies and Surface Coverage of Electroactive GroupsELECTROANALYSIS, Issue 21 2004Yunfeng Wang Abstract Ferrocene derivatives containing primary amines and maleimide groups were attached covalently onto N -hydrosuccinimidyl (NHS)-terminated alkanethiol self-assembled monolayers (SAMs) and SAMs of alkanedithiol. The surface coverage and efficiencies of the two cross-linking reactions were evaluated with cyclic voltammetry. All the ferrocene derivatives attached onto the alkanethiol or alkanedithiol SAMs exhibit reversible redox waves. The surface coverage of the aminated ferrocene groups was compared to that of N -hydrosuccinimidyl (NHS)-terminated alkanethiol SAM. The covalent attachment of ,-ferrocenylethylamine onto a 11,11,-dithio-bis(succinimidylundecanoate) SAM yielded an efficiency as high as 63.1%. The cross-linking efficiency of this reaction was found to increase with the nucleophilicity of the amino groups. SAMs of longer alkyl chains favor the attachment of a greater number of ferrocene derivatives. As for the Michael-type electrophilic addition between the sulfhydryl groups of the alkanedithiol SAMs and the ferrocenyl maleimide, the cross-linking efficiencies were found to range from 6.5% to 25.7%, depending on the alkanedithiol chain length. The difference in the efficiencies between the two types of cross-linking reactions might be partially attributable to the steric hindrance imposed by the SAMs and the relative sizes of the functional groups. [source] A Synthesis Detour to Planar-Diastereoisomeric Ferrocene Derivatives around an Unexpected Rearrangement of ortho -Lithiated Kagan's Template [S(S)] - (p -Tolylsulfinyl)ferroceneHELVETICA CHIMICA ACTA, Issue 4 2007Immo Weber Abstract Usually, ortho lithiation of Kagan's template 1 and quenching with electrophiles leads highly diastereoselectively to planar-chiral 1,2-disubstituted ferrocenes. Surprisingly, lithiation of 1 with lithium diisopropylamide (LDA) followed by addition of paraformaldehyde afforded regioisomer (+)-{[S(S)] - [4-(2-hydroxyethyl)phenyl]sulfinyl}ferrocene (2), which was converted to (+)-{[S(S)] - {4-{2-[(methylsulfonyl)oxy]ethyl}phenyl}sulfinyl}ferrocene (3) (Scheme,1). The desired diastereoisomer (l)-1-(hydroxymethyl)-2-(p -tolylsulfinyl)ferrocene (5) in turn could also be obtained by ortho lithiation of 1 with LDA but by quenching with DMF to yield aldehyde 4 first, which then was reduced with NaBH4 to 5. Finally, target compound (l)-1-[(dimethylamino)methyl]-2-(p -tolylsulfinyl)ferrocene (6) was obtained by substitution of the OH group of 5 under mild conditions or directly by ortho lithiation of 1 with lithio-2,4,6-triisopropylbenzene (=2,4,6-triisopropylphenyl)lithium; LTP) followed by quenching with N,N -dimethylmethyleneiminium chloride. At low temperatures, reaction of 1 with LDA leads, via the preferred diastereoisomeric transition state ,exo'- 7 and under extrusion of a (diisopropylamine)lithium complex of type 8, in a highly selective manner, to diastereoisomeric ortho -lithiated chelate (l)- 9 (Scheme,2). The reaction of 1 to 2 is explained by a rearrangement of (l)- 9 to {[S(S)],[4-(lithiomethyl)phenyl]sulfinyl}ferrocene 10, which is acid-catalyzed by coordinated diisopropylamine in complexes of type 8. This rearrangement is not observed if LTP is used as base or, in case LDA is applied, if the electrophile is sufficiently reactive at low temperatures. [source] Attachment of Amine- and Maleimide-Containing Ferrocene Derivatives onto Self-Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross-Linking Efficiencies and Surface Coverage of Electroactive GroupsELECTROANALYSIS, Issue 21 2004Yunfeng Wang Abstract Ferrocene derivatives containing primary amines and maleimide groups were attached covalently onto N -hydrosuccinimidyl (NHS)-terminated alkanethiol self-assembled monolayers (SAMs) and SAMs of alkanedithiol. The surface coverage and efficiencies of the two cross-linking reactions were evaluated with cyclic voltammetry. All the ferrocene derivatives attached onto the alkanethiol or alkanedithiol SAMs exhibit reversible redox waves. The surface coverage of the aminated ferrocene groups was compared to that of N -hydrosuccinimidyl (NHS)-terminated alkanethiol SAM. The covalent attachment of ,-ferrocenylethylamine onto a 11,11,-dithio-bis(succinimidylundecanoate) SAM yielded an efficiency as high as 63.1%. The cross-linking efficiency of this reaction was found to increase with the nucleophilicity of the amino groups. SAMs of longer alkyl chains favor the attachment of a greater number of ferrocene derivatives. As for the Michael-type electrophilic addition between the sulfhydryl groups of the alkanedithiol SAMs and the ferrocenyl maleimide, the cross-linking efficiencies were found to range from 6.5% to 25.7%, depending on the alkanedithiol chain length. The difference in the efficiencies between the two types of cross-linking reactions might be partially attributable to the steric hindrance imposed by the SAMs and the relative sizes of the functional groups. [source] Facile Access to Optically Active Ferrocenyl Derivatives with Direct Substitution of the Hydroxy Group Catalyzed by Indium TribromideEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2007Paola Vicennati Abstract Ferrocene derivatives have found many different uses and applications in organometallic chemistry, material chemistry, and catalysis. We have shown that using a catalytic amount (5,10 mol-%) of commercially available indium tribromide, at room temperature, many carbon nucleophiles, such as indoles, allylsilane, enolsilane, silyl ketene acetal, diketone, and trimethylsilylcyanide, smoothly react with different optically active ferrocenyl alcohol derivatives to afford the desired products in high yield, with retention of configuration. Also, many different N-nucleophiles (azide, carbamates) and O-nucleophiles (alcohols) react as well, again with retention of configuration. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Attachment of Amine- and Maleimide-Containing Ferrocene Derivatives onto Self-Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross-Linking Efficiencies and Surface Coverage of Electroactive GroupsELECTROANALYSIS, Issue 21 2004Yunfeng Wang Abstract Ferrocene derivatives containing primary amines and maleimide groups were attached covalently onto N -hydrosuccinimidyl (NHS)-terminated alkanethiol self-assembled monolayers (SAMs) and SAMs of alkanedithiol. The surface coverage and efficiencies of the two cross-linking reactions were evaluated with cyclic voltammetry. All the ferrocene derivatives attached onto the alkanethiol or alkanedithiol SAMs exhibit reversible redox waves. The surface coverage of the aminated ferrocene groups was compared to that of N -hydrosuccinimidyl (NHS)-terminated alkanethiol SAM. The covalent attachment of ,-ferrocenylethylamine onto a 11,11,-dithio-bis(succinimidylundecanoate) SAM yielded an efficiency as high as 63.1%. The cross-linking efficiency of this reaction was found to increase with the nucleophilicity of the amino groups. SAMs of longer alkyl chains favor the attachment of a greater number of ferrocene derivatives. As for the Michael-type electrophilic addition between the sulfhydryl groups of the alkanedithiol SAMs and the ferrocenyl maleimide, the cross-linking efficiencies were found to range from 6.5% to 25.7%, depending on the alkanedithiol chain length. The difference in the efficiencies between the two types of cross-linking reactions might be partially attributable to the steric hindrance imposed by the SAMs and the relative sizes of the functional groups. [source] Synthetic, Structural, and Electrochemical Studies of 2-Ferrocenyl- and2-Cymantrenyl-Functionalized 2,3-Dihydro-1H -1,3,2-diazaboroles and1,3,2-DiazaborolidenesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2005Lothar Weber Abstract Reaction of (dibromoboryl)ferrocene (1) with 1 equiv. of the diazabutadiene tBuN=CH,CH=NtBu, and subsequent reduction of the obtained borolium salt 2 with sodium amalgam, affords the first ferrocenyl-functionalized 1,3,2-diazaborole (3). Similarly, 1,1,-bis(dibromoboryl)ferrocene (4) can be transformed into compound 6, which contains two diazaborolyl substituents at the ferrocene core. Treatment of precursors 1 and 4 with 1,2-bis(tert -butylamino)ethane in the presence of Et3N gives rise to the formation of the diazaborolidine derivatives 13 and 14. 1-Dibromoboryl-3-methylcymantrene (7) was also treated with tBuN=CH,CH=NtBu to give the borolium salt 8, which was subsequently reduced to the 2-cymantrenyl-diazaborole 9. Treatment of 7 with tBuN(H)CH2CH2N(H)tBu in the presence of Et3N furnished the corresponding 2-cymantrenyl-diazaborolidine 15. The novel compounds were characterized by elemental analyses and various spectroscopic techniques (IR; 1H, 13C, and 11B NMR; MS). The molecular structures of 3, 6, and 15 were elucidated by X-ray diffraction analyses. Cyclovoltammetric studies of the ferrocene derivatives at high scan rates show features of a quasireversible oxidation at the iron center. The heterocyclic groups serve as electron donors, considerably lowering the oxidation potential of the central iron atoms when compared to the parent compound ferrocene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] The First Anionic Thia-Fries Rearrangements at Ferrocene: Ready Access to Trifluoromethylsulfonyl-Substituted Hydroxyferrocenes and an Extremely High Interannular Stereoinduction between Cyclopentadienyl LigandsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 8 2010Georg 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] | ||||||||||