1271-42-7Relevant academic research and scientific papers
Anionic thia-fries rearrangements of electron-rich ferrocenes and the unanticipated formation of diferrocenyl sulfate from 2-(trimethylsilyl) ferrocenyl imidazolylsulfonate
Werner, Georg,Butenschoen, Holger
, p. 5798 - 5809 (2013)
Upon ortho lithiation ferrocenyl triflate and 1,1′-ferrocenediyl ditriflate undergo anionic thia-Fries rearrangements instead of triflate elimination. To differentiate between an ortho metalation and an ortho deprotonation, 2-(trimethylsilyl)ferrocenyl triflate was shown to undergo an anionic thia-Fries rearrangement to 2-((trifluoromethyl)sulfonyl)ferrocenol (5) in 84% yield upon treatment with tetrabutylammonium fluoride. Metalation of the respective tributylstannyl derivative with butyllithium also led to 5 in 99% yield as the result of the anionic thia-Fries rearrangement. 2-Methoxyferrocenyl triflate also underwent the rearrangement upon ortho deprotonation with lithium diisopropylamide in practically quantitative yield at low temperature. The electron-rich 2-(((trifluoromethyl)sulfonyl)oxy)ferrocenolate was generated from 2-(((trifluoromethyl)sulfonyl)oxy)ferrocenyl acetate. However, ortho deprotonation again afforded the anionic thia-Fries rearrangement product. These results clearly show that even very electron rich ferrocene derivatives undergo an anionic thia-Fries rearrangement instead of a triflate elimination. In an attempt to induce an elimination supported by steric crowding, 2,3,4-trimethylferrocenyl triflate was deprotonated, giving 3,4,5-trimethyl-2- ((trifluoromethyl)sulfonyl)ferrocenol in quantitative yield as the result of an anionic thia-Fries rearrangement. As an alternative to the triflates ferrocenyl imidazolylsulfonate was tested as the starting material. While this compound could not be deprotonated, the corresponding 2-trimethylsilyl derivative reacted with tetrabutylammonium fluoride in a very unusual reaction to give diferrocenyl sulfate in almost quantitative yield.
From 2- to 3-Substituted Ferrocene Carboxamides or How to Apply Halogen dance to the Ferrocene Series
Tazi, Mehdi,Erb, William,Halauko, Yury S.,Ivashkevich, Oleg A.,Matulis, Vadim E.,Roisnel, Thierry,Dorcet, Vincent,Mongin, Florence
, p. 4770 - 4778 (2017)
Two methods were compared to convert ferrocene into N,N-diisopropylferrocenecarboxamide, N,N-diethylferrocenecarboxamide, N,N-dimethylferrocenecarboxamide, and (4-morpholinocarbonyl)ferrocene, namely, deprotometalation followed by trapping using dialkylcarbamoyl chlorides and amide formation from the intermediate carboxylic acid. The four ferrocenecarboxamides were functionalized at C2 in the case of the less hindered and more sensitive amides, recourse to a mixed lithium-zinc 2,2,6,6-tetramethylpiperidino-based base allowed us to achieve the reactions. Halogen migration using lithium amides was next optimized. Whereas it appeared impossible to isolate the less hindered 3-iodoferrocenecarboxamides, 3-iodo-N,N-diisopropylferrocenecarboxamide proved stable and was converted to new 1,3-disubstituted ferrocenes by Suzuki coupling or amide reduction. DFT calculations were used to rationalize the results obtained.
Synthesis and structure of novel chiral oxazolinylferrocenes and oxazolinylferrocenylphosphines, and their rhodium(I) -complexes
Nishibayashi, Yoshiaki,Segawa, Kyohei,Arikawa, Yasuyoshi,Ohe, Kouichi,Hidai, Masanobu,Uemura, Sakae
, p. 381 - 398 (1997)
A variety of chiral oxazolinylferrocenes are prepared from either ferrocenecarboxylic acid or cyanoferrocene and chiral β-amino alcohols. Highly diastereoselective ortho-lithiation (84 ～ 99% de) of the oxazolinylferrocenes is accomplished with sec-butyllithium and the treatment of the lithiated compounds with an electrophile such as MeI, Ph2PCI or (PhSe)2 gives the corresponding ortho-substituted oxazolinylferrocenes. The molecular structure of (S,S)-[2-(4′-isopropyloxazolin-2′-yl)ferrocenyl]diphenylphosphine (10), (S,S)-2-phenylseleno-1-(4′-isopropyloxazolinyl)ferrocene (17), (S,R)-3-methyl-1-diphenylphosphino-2-(4′-isopropyloxazolinyl)ferrocene (18), and (S,S,S)-[2-(4′,5′-diphenyloxazolin-2′-yl)ferrocenyl]diphenylphosphine ((S,S,S)-DIPOF; 21) has been fully characterized by X-ray crystallography. In connection with their usefulness as chiral ligands for Rh(I)-catalyzed asymmetric hydrosilylation of ketones, the square planar transition metal complexes having oxazolinylferrocenylphosphines, such as [Rh(COD)(P-N)]BF4 and Rh(CO)(P-N)Cl (P-N = 10 or 21), are prepared by treatment of [Rh(COD)2]BF4 and [Rh(CO)2Cl]2 with 10 and 21, respectively, and all structures have been characterized spectroscopically and further confirmed by X-ray crystallography.
Independent Quantification of Electron and Ion Diffusion in Metallocene-Doped Metal-Organic Frameworks Thin Films
Celis-Salazar, Paula J.,Cai, Meng,Cucinell, Clark A.,Ahrenholtz, Spencer R.,Epley, Charity C.,Usov, Pavel M.,Morris, Amanda J.
, p. 11947 - 11953 (2019)
The chronoamperometric response (I vs t) of three metallocene-doped metal-organic frameworks (MOFs) thin films (M-NU-1000, M = Fe, Ru, Os) in two different electrolytes (tetrabutylammonium hexafluorophosphate [TBAPF6] and tetrabutylammonium tetrakis(pentafluorophenyl)borate [TBATFAB]) was utilized to elucidate the diffusion coefficients of electrons and ions (De and Di, respectively) through the structure in response to an oxidizing applied bias. The application of a theoretical model for solid state voltammetry to the experimental data revealed that the diffusion of ions is the rate-determining step at the three different time stages of the electrochemical transformation: an initial stage characterized by rapid electron diffusion along the crystal-solution boundary (stage A), a second stage that represents the diffusion of electrons and ions into the bulk of the MOF crystallite (stage B), and a final period of the conversion dominated only by the diffusion of ions (stage C). Remarkably, electron diffusion (De) increased in the order of Fe 6 1- as the counteranion in all the stages of the voltammogram, demonstrating the strategy to modulate the rate of electron transport through the incorporation of rapidly self-exchanging molecular moieties into the MOF structure. The De values obtained with larger TFAB1- counteranion were generally in agreement with the previous trend but were on average lower than those obtained with PF6 1-. Similarly, the ion diffusion coefficient (Di) was generally higher for TFAB1- than for PF6 1- as the ions diffuse into the crystal bulk, due to the high degree of ion-pair association between PF6 1- and the metallocenium ion, resulting in a faster penetration of the weakly associated TFAB1- anion through the MOF pores. These structure-function relationships provide a foundation for the future design, control, and optimization of electron and ion transport properties in MOF thin films.
Synthesis and Structure of Planar Chiral, Bifunctional Aminoboronic Acid Ferrocene Derivatives
Batsanov, Andrei S.,Herault, Damien,Howard, Judith A. K.,Patrick, Leonard G. F.,Probert, Michael R.,Whiting, Andrew
, p. 2414 - 2419 (2007)
N,N′-Diisopropylferrocenecarboxamide is utilized for an asymmetric, directed metalation approach to several planar chiral bifunctional ferrocene derivatives. Directed metalation using n-butyllithium-(-)-sparteine on N,N′-diisopropylferrocenecarboxamide can be achieved to give high yields of the corresponding boronic acid; however, it was found that a sequence involving asymmetric directed metalation-bromination, followed by lithium-halogen exchange, was more convenient to access the same derivatives since this allowed straightforward determination of the enantiomeric excess. (pR)-2-[(N,N′-Diisopropylamino)methyl]ferrocenylboronic acid and derivatives thereof could be readily accessed with high enantiomeric excess, followed by amide reduction.
Chiral and Redox-Active Room-Temperature Ionic Liquids Based on Ferrocene and l-Proline
Bouvet, Carola B.,Krautscheid, Harald
, p. 4573 - 4580 (2016)
The syntheses of room-temperature ionic liquids (RTILs) combining the naturally occurring amino acid l-proline and ferrocene (Fc) building blocks are reported. After quaternization of ({[(2S)-N-methylpyrrolidine-2-yl]methyleneoxy}carbonyl)ferrocene (1) with alkyl iodides and anion exchange, the resulting diastereomeric (1S,2S)- and (1R,2S)-[(ferrocenylcarbonyl)oxy]methylene-N,N-dialkylpyrrolidine-1-ium RTILs are redox-active and air- and water-stable. They are also thermally stable up to 263 °C. The electrochemical FeII/FeIIIpotential is shifted to +0.28 V versus Fc/Fc+. Before anion exchange, several iodide derivatives were obtained as crystalline products, and their crystal structures are reported. According to the NMR spectroscopic data cation–anion aggregates are present in the non-coordinating solvent CDCl3. In contrast, in the polar solvent [D6]dimethyl sulfoxide ([D6]DMSO), the ion pairs are separated.
Synthesis, spectroscopy, electrochemistry and DFT of electron-rich ferrocenylsubphthalocyanines
Conradie, Jeanet,Swarts, Pieter J.
, (2020)
A series of novel ferrocenylsubphthalocyanine dyads Y-BSubPc(H)12 with ferrocenylcarboxylic acids Y-H = (FcCH2CO2-H), (Fc(CH2)3CO2-H) or (FcCO(CH2)2CO2-H) in the axial position were synthesized from the parent Cl-BSubPc(H)12 via an activated triflate-SubPc intermediate. UV/Vis data revealed that the axial ferrocenyl-containing ligand did not influence the Q-band maxima compared to Cl-BSubPc(H)12. A combined electrochemical and density functional theory (DFT) study showed that Fe group of the ferrocenyl-containing axial ligand is involved in the first reversible oxidation process, followed by a second oxidation localized on the macrocycle of the subphthalocyanine. Both observed reductions were ring-based. It was found that the novel Fc(CH2)3CO2BSubPc(H)12 exhibited the lowest first macrocycle-based reduction potential (-1.871Vvs. Fc/Fc+) reported for SubPcs till date. The oxidation and reduction values of Fc(CH2)nCO2BSubPc(H)12 (n = 0-3), FcCO(CH2)2CO2BSubPc(H)12, and Cl-BSubPc(H)12 illustrated the electronic influence of the carboxyl group, the different alkyl chains and the ferrocenyl group in the axial ligand on the ring-based oxidation and reduction values of the SubPcs.
Ferrocenecarboxylic acid and microwave-assisted synthesis of ferrocenoyl hydrazones
Kulikov,Nikulin,Arkhipov,Rodionov,Babusenko,Kovalenko,Belousov, Yu. A.
, p. 537 - 544 (2017)
A protocol to access ferrocenecarboxylic acid via carboxylation of ferrocene with carbon dioxide in the presence of aluminum chloride was elaborated. An efficient microwave-assisted synthesis of ferrocenoyl hydrazones by condensation of ferrocene carbohydrazide with carbonyl compounds was developed. Structures of the synthesized compounds were examined by NMR spectroscopy and mass spectrometry. Structures of N′-(4-chlorobenzylidene)ferrocenecarbohydrazide, N′-(4-methoxybenzylidene)ferrocenecarbohydrazide, and N′-(2-hydroxybenzylidene)ferrocenecarbohydrazide were determined by X-ray diffraction analysis. Synthesized compounds were found to have no toxicity against P. aeruginosa, E. coli, S. aureus, B. subtilis, M. rubrum, and C. albicans.
Carbon-Rich Trinuclear Octamethylferrocenophanes
Roemer, Max,Wild, Duncan A.,Sobolev, Alexandre N.,Skelton, Brian W.,Nealon, Gareth L.,Piggott, Matthew J.,Koutsantonis, George A.
, p. 3789 - 3799 (2019)
Several trinuclear ferrocenes are obtained by Friedel-Crafts reaction of octamethylferrocene with ferrocenoyl chloride and subsequent modifications. 1,1′-Diferrocenoyloctamethylferrocene (3) is transformed to the divinyl derivative (4a) by reaction with MeLi and AlCl3. The reactive 4a cyclizes spontaneously to a [4]ferrocenophane with buta-1,3-diene handle (5) or in the presence of AlCl3 to a [3]ferrocenophane with propene handle (6). Structure assignments are supported by X-ray crystallography and NMR spectroscopy, and mechanisms are proposed. Electrochemical behavior of the compounds was investigated with cyclic voltammetry, and assignments of the redox processes were carried out with the aid of density functional theory calculations. The synthesized compounds and demonstrated transformations represent useful tools for preparation of materials for charge-transport studies in metal-molecule-metal junctions.
Reduction of Escherichia coli ribonucleotide reductase subunit R2 with eight water-soluble ferrocene derivatives
Liu, Aimin,Leese, David N.,Swarts, Jannie C.,Sykes
, p. 83 - 90 (2002)
Water soluble ferrocenes [Fe(Cp)(CpL)], where Cp- is the η5-cyclopentadienide ligand and the side chain L is (a) the carboxylic acid group -(CH2)xCO2H with x=0-4 (I-V); (b) the complex x=2 with the β-methylene mono-methyl substituted (VI); (c) the amine hydrochloride derivative with L=CH(Me) NH3+ (VII); and (d) the complex with two Cp rings bridged by the amine hydrochloride -CH(NH3+)CH2CH2- (VIII); have been prepared, and are used as one-equivalent reductants for the active-R2 subunit of Escherichia coli ribonucleotide reductase. Formal reduction potentials E1°′ (25°C) of the carboxylates of acids I-VI in 20 mM NaOH, and of the amine hydrochlorides VII and VIII in water were determined by cyclic voltammetry, and are in the range 0.308-0.550 V versus nhe, I=0.100 M (NaCl). Second-order rate constants k12 (25°C) for the reduction of active-R2 were determined by UV-Vis spectrophotometry, and are in the range 0.15-0.50 M-1 s-1 at I=0.100 M. A free-energy plot of logk12 versus E°′ values gives no clearcut unidirectional trend. Since from present information the electron self-exchange rate constant for the [Fe(Cp)2]+/[Fe(Cp)2] couple is favourable (>7×106 M-1 s-1 in methanol at 25°C), it would appear that electron-transfer from the ferrocenes via Trp-48, Asp-237, His-118 to the FeIII2 site on R2 is much slower than expected, and smaller than with the organic radical reductants previously studied. Electron-transfer from some other position on the protein surface to the Tyr· is considered as an alternative.
