- The Unusual Redox Properties of Fluoroferrocenes Revealed through a Comprehensive Study of the Haloferrocenes
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We report the synthesis and full characterization of the entire haloferrocene (FcX) and 1,1′-dihaloferrocene (fcX2) series (X = I, Br, Cl, F; Fc = ferrocenyl, fc = ferrocene-1,1′-diyl). Finalization of this simple, yet intriguing set of compoun
- Inkpen, Michael S.,Du, Shuoren,Hildebrand, Mariana,White, Andrew J. P.,Harrison, Nicholas M.,Albrecht, Tim,Long, Nicholas J.
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- Coordination chemistry of perhalogenated cyclopentadienes and alkynes. Part 30. New high-yield syntheses of monochloroferrocene and 1,2,3,4,5- pentachloroferrocene. Molecular structures of 1,2-dichloroferrocene and 1,2,3-trichloroferrocene
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Lithiation of ferrocene with KOtBu and tBuLi in tetrahydrofuran at -78 °C, followed by treatment with hexachloroethane gives monochloroferrocene 1 in essentially quantitative yield. Lithiation of 1 with 1.2 equiv. lithium tetramethylpiperidide (LiTMP) in THF and chlorination with C2Cl6 gives 1,2-dichloroferrocene 2 contaminated with 1 and ferrocene. Treatment of this mixture with a tenfold excess of LiTMP and C2Cl6 yields after workup 1,2,3,4,5-pentachloroferrocene 3 in 29% yield based on ferrocene. Alternatively, from this mixture of 1 and 2 1,2,3-trichloroferrocene 4 and 1,2,3,4-tetrachloroferrocene 5 can be prepared in a stepwise fashion with yields of 40% and 46%, respectively. The molecular structures of 2 and 4 have been determined by X-ray diffraction and prove the postulated regiochemistry.
- Bernhartzeder, Stefanie,Sünkel, Karlheinz
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- Evidence for “Halogen-Dance” and Ring-Exchange Reactions in Chloro-methylthio-ferrocenes
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The pentachloroferrocenes [C5Cl5]Fe[C5H4X] (X = H, Br, SMe) react with LiTMP and MeSSMe to form mixtures of compounds, that contain besides the expected products of deprotonation also one or more complexes with a [C5Cl4(SMe)] ligand. This latter observation makes the otherwise rarely observed occurrence of “halogen dance reactions” in chloroaromatics very probable. 1,2,3-Trichloroferrocene yields with BuLi and MeSSMe products of both halogen-metal-exchange and of deprotonation. Additionally, in all examined systems, the observation of some highly-substituted complexes with eight or more substituents hints to the involvement of cyclopentadienyl exchange reactions, which has also rarely been observed under such mild conditions. The molecular structures of [C5Cl4(SMe)]Fe[C5H3BrX] (X = SMe or SOMe), [C5Cl4(SMe)]Fe[C5H2Cl(SMe)2], [C5Cl2(SMe)3]2Fe, and [C5HCl3(SMe)]2Fe have been determined by X-ray diffraction.
- Blockhaus, Tobias,Bernhartzeder, Stefanie,Kempinger, Werner,Klein-He?ling, Christian,Weigand, Stefan,Sünkel, Karlheinz
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- The gas-phase structure of chloroferrocene from microwave spectra
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Rotational spectra for ten isotopomers of chloroferrocene were measured using pulsed-beam Fourier transform microwave spectroscopy. Rotational transitions due to both a and b dipole moments were measured in the 4-12 GHz range. Thirty rotational constants were determined from microwave data for the normal, 54Fe, 57Fe, 37Cl, and six unique 13C isotopomers, by fitting the microwave data using a rigid rotor Hamiltonian with centrifugal distortion and quadrupole coupling terms. The moments of inertia of the isotopomers were used in Kraitchman and in least-squares fitting analyses to determine gas-phase structural parameters. The unsubstituted cyclopentadienyl (C5H5) ligand was determined to have essentially fivefold local symmetry, while the chlorinated cyclopentadienyl ligand shows small, but significant distortions from the fivefold symmetry. The C-Cl bond is bent 2.7(6)° from the plane of carbon atoms. This substituted C5H4Cl ligand is tilted 1.4(5)° with respect to the unsubstituted C5H5 ligand. The carbon atoms of the two cyclopentadienyl ligands are eclipsed, similar to normal ferrocene. The average Fe-C distance is 2.042(9) A. The estimated displacement of C-H bonds out of the planes of the carbon atoms is 4(2)° away from the metal atom.
- Drouin, Brian J.,Dannemiller, Jennifer J.,Kukolich, Stephen G.
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- Regorafenib analogues and their ferrocenic counterparts: Synthesis and biological evaluation
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Approved by the FDA in 2012, regorafenib is one of the last chance treatments for colorectal cancer. While various analogues have already been prepared, ferrocenic derivatives have never been evaluated. In this study, we prepared various ferrocene-containing derivatives of regorafenib and recorded their biological activity in kinase and cellular assays. This led to the identification of a squaramide derivative which shows a good cellular activity and three ferrocene analogues with promising activity in both kinase and cellular assays. This journal is
- Wilde, Myron,Arzur, Danielle,Baratte, Blandine,Lefebvre, Dorian,Robert, Thomas,Roisnel, Thierry,Le Jossic-Corcos, Catherine,Bach, Stéphane,Corcos, Laurent,Erb, William
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supporting information
p. 19723 - 19733
(2020/12/04)
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- Halide-Mediated Ortho-Deprotonation Reactions Applied to the Synthesis of 1,2- and 1,3-Disubstituted Ferrocene Derivatives
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The ortho-deprotonation of halide-substituted ferrocenes by treatment with lithium tetramethylpiperidide (LiTMP) has been investigated. Iodo-, bromo-, and chloro-substituted ferrocenes were easily deprotonated adjacent to the halide substituents. The synthetic applicability of this reaction was, however, limited by the fact that, depending on the temperature and the degree of halide substitution, scrambling of both iodo and bromo substituents at the ferrocene core took place. Iodoferrocenes could not be transformed selectively into ortho-substituted iodoferrocenes since, in the presence of LiTMP, the iodo substituents scrambled efficiently even at -78°C, and this process had occurred before electrophiles had been added. Bromoferrocene and certain monobromo-substituted derivatives, however, could be efficiently ortho-deprotonated at low temperature and reacted with a number of electrophiles to afford 1,2- and 1,2,3-substituted ferrocene derivatives. For example, 2-bromo-1-iodoferrocene was synthesized by ortho-deprotonation of bromoferrocene and reaction with the electrophiles diiodoethane and diiodotetrafluoroethane, respectively. In this and related cases the iodide scrambling process and further product deprotonation due to the excess LiTMP could be suppressed efficiently by running the reaction at low temperature and in inverse mode. In contrast to the low-temperature process, at room temperature bromo substituents in bromoferrocenes scrambled in the presence of LiTMP. Chloro- and 1,2-dichloroferrocene could be ortho-deprotonated selectively, but in neither case was scrambling of a chloro substituent observed. As a further application of this ortho-deprotonation reaction, a route for the synthesis of 1,3-disubstituted ferrocenes was developed. 1,3-Diiodoferrocene was accessible from bromoferrocene in four steps. On a multigram scale an overall yield of 41% was achieved. 1,3-Diiodoferrocene was further transformed into symmetrically 1,3-disubstituted ferrocenes (1,3-R2Fc; R = CHO, COOEt, CN, CH = CH2). (Figure Presented).
- Zirakzadeh, Afrooz,Herlein, Alexander,Gross, Manuela A.,Mereiter, Kurt,Wang, Yaping,Weissensteiner, Walter
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p. 3820 - 3832
(2015/08/24)
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- BASELESS NUCLEOTIDE ANALOGUES AND USES THEREOF
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A method of detecting a target nucleic acid.
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Paragraph 0112; 0113
(2014/05/07)
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- 1,1 '-[[(SUBSTITUTED ALKYL)IMINO]BIS(ALKYLENE)]BIS-FERROCENES AND THEIR USE IN I ELECTROCHEMICAL ASSAYS BY LABELLING SUBSTRATES OF INTEREST
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Compounds of general formula I wherein Fc and Fc' may be the same or different and are substituted ferrocenyl moieties having at least one ring substituent selected from sulfur- containing groups, phosphorus-containing groups, iodo, chloro, silyl, fluoroa
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Page/Page column 35
(2014/01/09)
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- Acceptor-substituted ferrocenium salts as strong, single-electron oxidants: Synthesis, electrochemistry, theoretical investigations, and initial synthetic application
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A series of mono- and 1,1'-diheteroatom-substituted ferrocene derivatives as well as acylated ferrocenes was prepared efficiently by a unified strategy that consists of selective mono- and 1,1'-dilithiation reactions and subsequent coupling with carbon, phosphorus, sulfur and halogen electrophiles. Chemical oxidation of the ferrocene derivatives by benzoquinone, 2,3-dichloro-5,6- dicyanobenzoquinone, AgPF6, or 2,2,6,6-tetramethyl-1-oxopiperidinium hexafluorophosphate provided the corresponding ferrocenium salts. The redox potentials of the synthesized ferrocenes were determined by cyclic voltammetry, and it was observed that all new ferrocenium salts have stronger oxidizing properties than standard ferrocenium hexafluorophosphate. An initial application of selected derivatives in an oxidative bicyclization revealed that they mediate the transformation under considerably milder conditions than ferrocenium hexafluorophosphate. Quantum chemical calculations of the reduction potentials of the substituted ferrocenium ions were carried out by using a standard thermodynamic cycle that involved the gas-phase energetics and solvation energies of the contributing species. A remarkable agreement between theory and experiment was found: the mean average deviation amounted to only 0.030-V and the maximum deviation to 0.1-V. This enabled the analysis of various physical contributions to the computed reduction potentials of these ferrocene derivatives, thereby providing insight into their electronic structure and physicochemical properties. Copyright
- Khobragade, Dushant A.,Mahamulkar, Shraddha G.,Pospí?il, Lubomír,Císa?ová, Ivana,Rulí?ek, Lubomír,Jahn, Ullrich
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supporting information
p. 12267 - 12277
(2012/11/14)
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- Analysis of Substituted Ferrocenes by Infrared Spectroscopy
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The i.r. spectra of substituted ferrocenes were investigated to determine and analyse the appropriate ring-metal stretching force constants.Assignment of the ring-mode vibrations is attempted.
- Phillips, Leonidas,Lacey, Anthony R.,Cooper, Mervyn K.
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p. 1383 - 1392
(2007/10/02)
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- Ferrocene Derivatives. Part 22. Friedel-Crafts Arylations with Chloroferrocenes. A New Route to Arylferrocenes.
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In the presence of anhydrous aluminium chloride and aluminium, chloro- and 1,1'-dichloro-ferrocenes act as moderately efficient reagents for the Friedel-Crafts arylation (i.e. 'ferrocenylation') of simple arenes.Extensive reductive dechlorination also occurs.
- Pauson, Peter L.,Sraga, Jan,Toma, Stefan
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p. 1233 - 1236
(2007/10/02)
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