Showing papers on "Ferrocene published in 2017"
TL;DR: Ferrocene's chemistry, properties, functions, and applications can be found in a literature survey by as discussed by the authors, with a focus on basic properties, including ligand-exchange reactions and the ferrocene/ferricinium redox couple.
Abstract: The appearance of ferrocene in the middle of the 20th century has revolutionized organometallic chemistry and is now providing applications in areas as varied and sometimes initially unexpected as optical and redox devices, battery and other materials, sensing, catalysis, including asymmetric and enantioselective catalysis, and medicine. The author presents here a general, although personal, view of ferrocene's chemistry, properties, functions, and applications through a literature survey involving both historical and up-to-date trends and including examples of his group's research in a number of these areas. The review gathers together general features of ferrocene chemistry and representative examples of the salient aspects. Its focus is on ferrocene's basic properties, ferrocene-containing ligands, the ferrocene/ferricinium redox couple, ferrocene mixed-valence and average-valence systems, the ferricinium/ferrocene redox shuttle in catalysis, ligand-exchange reactions, ferrocene-containing polymers, ferrocene-containing structures for cathodic battery and other materials, ferrocenes in supramolecular ensembles, liquid crystals, and nonlinear optical materials, ferrocene-containing stars and their electrostatic effects, ferrocene-containing dendrons, dendrimers, and nanoparticles (NPs) and their application in redox sensing and catalysis, and ferrocenes in nanomedicine.
384 citations
TL;DR: In this article, the authors demonstrate an aqueous organic and organometallic redox flow battery utilizing reactants composed of only earth-abundant elements and operating at neutral pH.
Abstract: We demonstrate an aqueous organic and organometallic redox flow battery utilizing reactants composed of only earth-abundant elements and operating at neutral pH. The positive electrolyte contains bis((3-trimethylammonio)propyl)ferrocene dichloride, and the negative electrolyte contains bis(3-trimethylammonio)propyl viologen tetrachloride; these are separated by an anion-conducting membrane passing chloride ions. Bis(trimethylammoniopropyl) functionalization leads to ∼2 M solubility for both reactants, suppresses higher-order chemical decomposition pathways, and reduces reactant crossover rates through the membrane. Unprecedented cycling stability was achieved with capacity retention of 99.9943%/cycle and 99.90%/day at a 1.3 M reactant concentration, increasing to 99.9989%/cycle and 99.967%/day at 0.75–1.00 M; these represent the highest capacity retention rates reported to date versus time and versus cycle number. We discuss opportunities for future performance improvement, including chemical modification...
367 citations
TL;DR: In this paper, a prototype of all-metallocene-based Li-RFB exploits ferrocene and cobaltocene (CoCp2) as the redox-active cathode and anode, respectively.
Abstract: Here, a class of organometallic compounds, metallocenes, are explored to serve as both catholyte and anolyte redox species for non-aqueous lithium-based redox flow battery (Li-RFB) applications. The prototype of all-metallocene-based Li-RFB exploits ferrocene (FeCp2) and cobaltocene (CoCp2) as the redox-active cathode and anode, respectively. The reaction rate constants of metallocenes are determined to be as high as 10−3 cm s−1, two orders greater than most redox-active materials applied in conventional redox flow batteries. This designed Li-RFB yields a working potential of 1.7 V, and by introduction of methyl groups on the ligand rings of CoCp2, the working potential can be further increased to 2.1 V. The fabricated full cell shows capacity retention of over 99% per cycle with a coulombic efficiency (CE) of >95% and an energy efficiency of >85%. These results demonstrate a generic design route towards high performance non-aqueous RFBs via rational screening and functionalization of metallocenes.
176 citations
TL;DR: A series of tridentate ferrocene-based amino-phosphine acid (f-Ampha) ligands have been successfully developed and exhibited excellent performance in the Ir-catalyzed asymmetric hydrogenation of ketones and it was revealed that the -COOH group played a key role in this reaction.
69 citations
TL;DR: A review of the properties of push-pull chromophores can be found in this article, where structure-property correlations have been drawn and structure correlations between the two types of materials have been analyzed.
64 citations
TL;DR: In this paper, the synthesis, characterization, and reactivity of an aluminum alkoxide complex supported by a ferrocene-based ligand, (thiolfan*)Al(OtBu) (1 red, thiolfan* = 1,1′-di(2,4-di-tert-butyl-6-thiophenoxy)ferrocene), are reported.
Abstract: The synthesis, characterization, and reactivity of an aluminum alkoxide complex supported by a ferrocene-based ligand, (thiolfan*)Al(OtBu) (1red, thiolfan* = 1,1′-di(2,4-di-tert-butyl-6-thiophenoxy)ferrocene), are reported. The homopolymers of l-lactide (LA), e-caprolactone (CL), δ-valerolactone (VL), cyclohexene oxide (CHO), trimethylene carbonate (TMC), and their copolymers were obtained in a controlled manner by using redox reagents. Detailed DFT calculations and experimental studies were performed to investigate the mechanism. Mechanistic studies show that, after the insertion of the first monomer, the coordination effect of the carbonyl group, which has usually been ignored in previous reports, can significantly change the energy barrier of the propagation steps, thus playing an important role in polymerization and copolymerization processes.
55 citations
TL;DR: A wide range of ferrocene-based alkynylation products could be obtained in up to 94% yield, and a gram-scale reaction also proceeded smoothly with high efficiency.
Abstract: Rapid access to mono- or dialkynylation of ferrocene with ethynylbenziodoxolones as the alkynylation reagents was achieved via rhodium-catalyzed direct C–H bond functionalization at room temperature. Mono- and dialkynylation were easily modulated by varying the sterical volume of the directing group, such as pyridine and isoquinoline, and amount of hypervalent iodine reagents. A wide range of ferrocene-based alkynylation products could be obtained in up to 94% yield, and a gram-scale reaction also proceeded smoothly with high efficiency.
52 citations
TL;DR: A neutral redox-active acyclic halogen bonding (XB) receptor with a ferrocene core functionalised at the 1,3-positions of a cyclopentadienyl ring with iodotriazole motifs is prepared in this paper.
Abstract: A neutral redox-active acyclic halogen bonding (XB) receptor with a ferrocene core functionalised at the 1,3-positions of a cyclopentadienyl ring with iodotriazole motifs is prepared. Owing to favourable host-guest size-complementarity, the receptor was found to be selective for azide over a diverse range of anions with different geometries. Voltammetric studies revealed the unique ability of the XB ferrocene receptor to selectively sense azide via a significant cathodic shift of its ferrocene/ferrocenium redox couple. Notably, much weaker binding of azide was observed for the hydrogen bonding 1,3-bis-prototriazole ferrocene receptor analogue, which also displayed a poorer electrochemical response, suggesting that halogen bonding interactions play crucial roles in the binding and sensing of azide.
44 citations
TL;DR: Ferrocene, Cp1 Fe, is quantitatively protonated in a mixture of liquid HF/PF5 to yield [Cp2 FeH](PF6 ), which was characterized by 1 H/13 C NMR and 57 Fe Mössbauer spectroscopy as well as single-crystal X-ray diffraction analysis.
Abstract: Ferrocene, Cp2Fe, is quantitatively protonated in a mixture of liquid HF/PF5 to yield [Cp2FeH](PF6), which was characterized by 1H and 13C NMR, 57Fe Mosbauer spectroscopy, and single-crystal X-ray diffraction analysis. The X-ray diffraction analysis at 100 K revealed a disordered, iron-coordinated hydrido ligand that was unambiguously located by aspherical atom refinement at 100 K and by analyzing the non-disordered crystal structure at 30 K, revealing a non-agostic structure.
41 citations
TL;DR: In this paper, the effect of TX-100 on the reactivity of FC molecules at the FMCPE interface was studied using the analytical Fukui and cyclic voltammetry (CV) to understand the electron transfer (ET) nature of ferrocene.
41 citations
TL;DR: Despite sterically accessible boron centers and facile electrochemical reductions, compound 2 is air-, moisture-, and silica gel-stable.
Abstract: Reaction of an N-heterocyclic carbene (NHC)–borenium ion with 9,10-distyrylanthracene forms four B−C bonds through two selective, tandem hydroboration–electrophilic C−H borylations to yield an isolable, crystallographically characterizable polycyclic diborenium ion as its [NTf2]− salt (1). Dehydrogenation of 1 with TEMPO radical followed by acidic workup yields a 3,9-diboraperylene as its corresponding borinic acid (2). This sequence can be performed in one pot to allow the facile, metal-free conversion of an alkene into a small molecule containing a boron-doped graphene substructure. Doubly boron-doped perylene 2 exhibits visible range absorbance and fluorescence in chloroform solution (Φ=0.63) and undergoes two reversible one-electron reductions at moderate potentials of −1.30 and −1.64 eV vs. ferrocenium/ferrocene in DMSO. Despite sterically accessible boron centers and facile electrochemical reductions, compound 2 is air-, moisture-, and silica gel-stable.
TL;DR: Interestingly, the as-formed hydrogels display an unusual, strongly hysteretic volume-phase transition indicating useful thermal memory properties, and represents a new dual-responsive materials platform.
Abstract: We report on the synthesis and structure–property relations of a novel, dual-responsive organometallic poly(ionic liquid) (PIL), consisting of a poly(ferrocenylsilane) backbone of alternating redox-active, silane-bridged ferrocene units and tetraalkylphosphonium sulfonate moieties in the side groups. This PIL is redox responsive due to the presence of ferrocene in the backbone and also exhibits a lower critical solution temperature (LCST)-type thermal responsive behavior. The LCST phase transition originates from the interaction between water molecules and the ionic substituents and shows a concentration-dependent, tunable transition temperature in aqueous solution. The PIL’s LCST-type transition temperature can also be influenced by varying the redox state of ferrocene in the polymer main chain. As the polymer can be readily cross-linked and is easily converted into hydrogels, it represents a new dual-responsive materials platform. Interestingly, the as-formed hydrogels display an unusual, strongly hyste...
TL;DR: A unique titanium oxo cluster with a ferrocene ligand was synthesized and characterized by single crystal X-ray analysis and electronic spectra and theoretical calculations indicate that charge transfer occurs from ferrocenes to Ti(IV) in 1, and the presence of theFerrocene moiety gives efficient electron excitation and charge separation.
Abstract: A unique titanium oxo cluster with a ferrocene ligand was synthesized and characterized by single crystal X-ray analysis Six ferrocene carboxylates coordinate to a D3d Ti6O6 core to be a redox active cluster 1, [Ti6O6(OiPr)6(O2CFc)6] An analogue 2, [Ti6O6(OiPr)6(O2CiBu)6], where the redox active ferrocene group is replaced by isobutyrate, is also reported as a contrast The six ferrocene moieties in 1 are structurally identical to give a main redox wave at E1/2 = 062 V in dichloromethane investigated by cyclic voltammetry Photocurrent responses using electrodes of clusters 1 and 2 were studied, and the response properties of 1 are better than those of 2 The electronic spectra and theoretical calculations indicate that charge transfer occurs from ferrocene to Ti(IV) in 1, and the presence of the ferrocene moiety gives efficient electron excitation and charge separation Cluster 1 is a cooperative system of TiO cluster and redox active ferrocene Photocurrent response properties of an electrode of 1 fo
TL;DR: The catalytic activity of complexes 1-3 was explored for O-arylation of phenol and Suzuki-Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides.
Abstract: Schiff base ligands (L1: sulfated and L2: selenated) having a ferrocene core synthesized by reacting ferrocene-carboxaldehyde with 2-(phenylthio/seleno)ethylamine on treatment with Na2PdCl4 in the presence of NaOAc give cyclopalladated complexes [Pd(L1/L2-H)Cl] (1/2). Complex 1 of a sulfated Schiff base L1, on reacting with one equivalent of triphenylphosphine gives complex [Pd(L1-H)PPh3Cl] (3), formed due to cleavage of a Pd-S bond. With 2 such a reaction does not occur, as a Pd-Se bond being stronger than that of its sulfur analogue does not get cleaved. L1, L2 and their complexes 1-3 were authenticated with HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectroscopy. The single crystal structures of 1-3 were determined with X-ray diffraction. Palladium in all three complexes has nearly a square planar geometry. The Pd-S, Pd-Se and Pd-P bond distances are 2.4249(12), 2.5058(14) and 2.2445(17) A respectively. The catalytic activity of complexes 1-3 was explored for O-arylation of phenol and Suzuki-Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides. The optimum reaction time for SMC of ArBr is 3 h whereas for ArCl it is 6 h. The TON values of O-arylation catalyzed with complexes 1-3 are up to ∼170 (TOF, 28 h-1) and SMC ∼9300 (TOF, 3100 h-1) for the reaction time of the order of 3 and 6 h respectively. The catalytic process is somewhat more efficient with 2 (Pd bonded with a selenoether group), than 3, followed by 1.
TL;DR: Efficient, elegant, and high‐yielding (for macrocyclic species) synthetic routes to two novel alkynyl‐conjugated multiple ferrocene‐ and biferrocenes‐containing cyclic compounds are presented.
Abstract: Cyclic multiredox centered systems are currently of great interest, with new compounds being reported and developments made in understanding their behavior. Efficient, elegant, and high-yielding (for macrocyclic species) synthetic routes to two novel alkynyl-conjugated multiple ferrocene- and biferrocene-containing cyclic compounds are presented. The electronic interactions between the individual ferrocene units have been investigated through electrochemistry, spectroelectrochemistry, density functional theory (DFT), and crystallography to understand the effect of cyclization on the electronic properties and structure.
TL;DR: In this article, a nanostructured redox-electrodes, functionalized with poly(vinyl)ferrocene embedded in a carbon nanotube matrix, was presented for modulating the adsorption and release of proteins through electrochemical potential swings.
Abstract: Redox-active materials are an attractive platform for engineering specific interactions with charged species by electrochemical control. We present nanostructured redox-electrodes, functionalized with poly(vinyl)ferrocene embedded in a carbon nanotube matrix, for modulating the adsorption and release of proteins through electrochemical potential swings. The affinity of the interface toward proteins increased dramatically following oxidation of the ferrocenes, and, due to the Faradaic nature of the organometallic centers, the electrodes were maintained at sufficiently low overpotentials to ensure the preservation of both protein structure and catalytic activity. Our system was selective for various proteins based on size and charge distribution, and exhibited fast kinetics ( 200 mg/g) under moderate overpotentials (+0.4 V vs Ag/AgCl), as well as remarkable stability for binding under ferrocene oxidation conditions. The preservation of bioacti...
TL;DR: It seems Fe(II) catalyst not only stabilizes the generated benzyl radical but also tames its oxidizing behavior, and consequently transfers it to the palladacycle for C-C coupling.
TL;DR: In this article, a novel ferrocene tethered N -heterocyclic carbene-Pd complex anchored on cellulose has been prepared by multi-step synthesis, which proved to be robust and efficient heterogeneous catalyst for synthesis of biaryls in Suzuki-Miyaura cross coupling reaction.
Abstract: A novel ferrocene tethered N -heterocyclic carbene-Pd complex anchored on cellulose has been prepared by multi-step synthesis. The complex proved to be robust and efficient heterogeneous catalyst for synthesis of biaryls in Suzuki-Miyaura cross coupling reaction.
01 Feb 2017
TL;DR: Anti-m migration studies show that 1G, 2G and 3G exhibit improved anti-migration behavior in the AP-based propellant.
Abstract: Ferrocene-based derivatives are widely used as ferrocene-based burning rate catalysts (BRCs) for ammonium perchlorate (AP)-based propellant. However, in long storage, small ferrocene-based derivatives migrate to the surface of the propellant, which results in changes in the designed burning parameters and finally causes unstable combustion. To retard the migration of ferrocene-based BRCs in the propellant and to increase the combustion of the solid propellant, zero to third generation ethylene diamine-based ferrocene terminated dendrimers (0G, 1G, 2G and 3G) were synthesized. The synthesis of these dendrimers was confirmed by 1H NMR and FT-IR spectroscopy. The electrochemical behavior of 0G, 1G, 2G and 3G was investigated by cyclic voltammetry (CV) and the burning rate catalytic activity of 0G, 1G, 2G and 3G on thermal disintegration of AP was examined by thermogravimetry (TG) and differential thermogravimetry (DTG) techniques. Anti-migration studies show that 1G, 2G and 3G exhibit improved anti-migration behavior in the AP-based propellant.
TL;DR: It is demonstrated that the introduction of ferrocene groups into the titanium-oxo cluster significantly reduces the band gap and enhances the photocurrent response in comparison with the naphthalene-sensitized clusters.
Abstract: Sensitized titanium-oxo clusters (TOCs) have attracted growing interest. However, reports on TOCs incorporated with a metal complex as photosensitizers are still very rare. In the present work, the organometallic complex ferrocene was used as a sensitizer for a titanium-oxo cluster. A ferrocenecarboxylate-substituted titanium-oxo cluster [Ti6(μ3-O)6(OiPr)6(O2CFc)6] (Fc = ferrocenyl) was synthesized and structurally characterized, in which the ferrocene wheel performs as a sensitizer for photocurrent response. For comparison, naphthalene-sensitized titanium-oxo clusters [Ti6(μ3-O)6(OiPr)6(NA)6] (NA = 1-naphthoate) and [Ti6(μ3-O)6(OiPr)6(NAA)6] (NAA = 1-naphthylacetate) with the same {Ti6} core structure were also synthesized. The structures, optical behaviors, electronic states and photoelectrochemical properties of these sensitized {Ti6} clusters were investigated. It is demonstrated that the introduction of ferrocene groups into the titanium-oxo cluster significantly reduces the band gap and enhances the photocurrent response in comparison with the naphthalene-sensitized clusters. The substantially reduced band gap of the ferrocene-sensitized cluster was attributed to the introduction of Fe(II) d–d transitions and the possible contribution from the Fc → {Ti6} charge transfer. For the naphthalene-sensitized clusters, the better electronic coupling between the dye and the {Ti6} core in the 1-naphthoate (NA) substituted cluster results in higher photoelectrochemical activity.
TL;DR: In this paper, the design and synthesize of a series of Dπ-A-π-D analogs were carried out by incorporating well-defined building blocks (ferrocene and pyran) with Knoevenagel condensation aiming to use them in optical applications.
TL;DR: Several BOPHY derivatives with and without ferrocene fragments, and with electron-withdrawing ester groups appended to the β-pyrrolic positions have been prepared and characterized by NMR, UV/Vis near-infrared (NIR), high-resolution mass spectrometry, and fluorescence spectroscopy, as well as X-ray crystallography.
Abstract: Several BOPHY derivatives with and without ferrocene fragments, and with electron-withdrawing ester groups appended to the β-pyrrolic positions have been prepared and characterized by NMR, UV/Vis near-infrared (NIR), high-resolution mass spectrometry, and fluorescence spectroscopy, as well as X-ray crystallography. The redox properties of new BOPHYs were probed by electrochemical (cyclic and differential pulse voltammetry) and spectroelectrochemical methods. In an attempt to prepare BOPHY derivatives with a cyano group at the bridging position using a similar approach for BODIPY cyanation, adducts from the nucleophilic attack of the cyanide anion on the bridging position in BOPHY have been isolated and characterized by spectroscopic methods. Oxidation of such adducts, however, resulted in formation of either the starting BOPHYs, or partial extrusion of the BF2 fragment from the BOPHY core, which was confirmed by spectroscopy and X-ray crystallography. DFT and TDDFT calculations on all target materials correlate well with the experimental data, and suggest the dramatic reduction of the nitrogen atom basicity at the hydrazine bridge of the BOPHY upon introduction of the cyano group at the bridging-carbon atom.
TL;DR: A reaction optimization strategy employing ligand parametrization led to the identification of 1,1'-bis[bis(dimethylamino)phosphino]ferrocene "DMAPF", a readily available yet previously unutilized diphosphine, as a uniquely effective ligand for this transformation.
Abstract: A new catalyst system capable of selective chloride functionalization in the Pd-catalyzed amination of 3,2- and 5,2- Br/Cl-pyridines is reported. A reaction optimization strategy employing ligand parametrization led to the identification of 1,1′-bis[bis(dimethylamino)phosphino]ferrocene “DMAPF”, a readily available yet previously unutilized diphosphine, as a uniquely effective ligand for this transformation.
TL;DR: In this article, a novel organometallic poly(ionic liquid) with both redox-and thermoresponsive properties is synthesized from a poly(ferrocenylsilane) (PFS) via a one-step Strecker sulfite alkylation reaction by using tetraalkylphosphonium sulfite as an effective and versatile nucleophile.
Abstract: A novel organometallic poly(ionic liquid) with both redox- and thermoresponsive properties is synthesized from a poly(ferrocenylsilane) (PFS) via a one-step Strecker sulfite alkylation reaction by using tetraalkylphosphonium sulfite as an effective and versatile nucleophile This dual-responsive polymer is composed of a PFS backbone and quaternary phosphonium sulfonate side groups and exhibits a concentration-dependent lower critical solution temperature (LCST)-type phase transition in aqueous solution Furthermore, the LCST-type phase behavior of the polymer can be switched between the “off” state and “on” state by chemical or electrochemical oxidation and reduction on the ferrocene units in the polymer main chain As a consequence, a classical LCST-type phase transition, as well as an “isothermal” redox-triggered phase transition can be induced by using thermal and electrochemical triggers without changing the composition of the system On the basis of this dual responsiveness, a “smart window” device is fabricated The optical characteristics of this device are completely unaltered after 100 thermal and/or redox cycles
TL;DR: In this paper, two methods were compared to convert ferrocene into N,N-diisopropylferrocenecarboxamide, N,D-diethylferrichenecaroxamides, and (4-morpholinocarbonyl)ferrocene, namely, deprotometalation followed by trapping using dialkyl carbamoyl chlorides and amide formation from the intermediate carboxylic acid.
TL;DR: In this article, a nonenzymatic catechol sensor based on the immobilization of ferrocene (Fc) on graphene oxide (GO) is presented, which is stable, reproducible and reasonably selective.
Abstract: The authors report on a nonenzymatic catechol sensor that is based on the immobilization of ferrocene (Fc) on graphene oxide (GO). A glassy carbon electrode (GCE) was modified with GO which then was silanized with (3-aminopropyl)trimethoxysilane. Ferrocenecarboxaldehyde was then immobilized on GO via formation of a Schiff base. The immobilization process was monitored stepwise by using FTIR spectroscopy, X-ray diffraction, cyclic voltammetry (CV) and electrochemical impedance spectroscopy. Investigation of the modified electrode by CV revealed a pair of well-defined redox peaks with anodic and cathodic peak potentials at +0.380 and +0.277 V, corresponding to the Fc/Fc+ redox couple. The Fc modified electrode exhibits excellent electrocatalytic activity towards the oxidation of catechol at a typical working voltage of +0.45 V (vs. Ag/AgCl). The response is linear in the 3 to 112 μM catechol concentration range, the detection limit is 1.1 μM, and the sensitivity is 1184.3 μA·mM−1·cm−2. The sensor is stable, reproducible and reasonably selective. It was successfully applied to the determination of catechol in spiked tap water and lake water samples.
TL;DR: The electronic structure, redox properties, and UV-vis spectra of new systems were correlated with Density Functional Theory (DFT) and time-dependent DFT calculations (TDDFT), which are suggestive of a ferrocene-centered highest occupied molecular orbital and chromophore-centered lowest unoccupied molecular orbital in 3 and 4.
Abstract: The 1,3,7,9-tetraferrocenylazadipyrromethene (3) and the corresponding 1,3,5,7-tetraferrocene aza-BODIPY (4) were prepared via three and four synthetic steps, respectively, starting from ferrocenecarbaldehyde using the chalcone-type synthetic methodology. The novel tetra-iron compounds have ferrocene groups directly attached to both the α- and the β-pyrrolic positions, and the shortest Fe–Fe distance determined by X-ray crystallography for 3 was found to be ∼6.98 A. These new compounds were characterized by UV–vis, nuclear magnetic resonance, and high-resolution electrospray ionization mass spectrometry methods, while metal–metal couplings in these systems were probed by electro- and spectroelectrochemistry, chemical oxidations, and Mossbauer spectroscopy. Electrochemical data are suggestive of the well-separated stepwise oxidations of all four ferrocene groups in 3 and 4, while spectroelectrochemical and chemical oxidation experiments allowed for characterization of the mixed-valence forms in the target ...
TL;DR: In this article, the results show that the ferrocene branched chitosan coated sensor has exhibited promising CO sensing property for CO sensor applications at room temperature at the same time.
Abstract: In this study ferrocene, chitosan and ferrocene branched chitosan were synthesized to investigate carbon monoxide (CO) sensing properties and adsorption characteristics. The range of 0–2000 ppm CO concentrations was used as active gas, high purity nitrogen (N 2 ) and air were used as cleaning gases for desorption process. Sorption data were collected by quartz crystal microbalance (QCM) technique. A sensitive film production on QCM was achieved via drop-casting method. Langmuir model was applied to clarify CO adsorption and the desorption kinetics of ferrocene, chitosan and ferrocene branched chitosan with respect to reference N 2 . The results show that the ferrocene branched chitosan coated sensor has exhibited promising CO sensing property for CO sensor applications at room temperature.
TL;DR: The newly synthesised compounds showed promising antitrypanosomal activity, and most of them were non-toxic to HL-60 cells, and it was found that cymantrene and cyrhetrene ketone nucleobases were more active than their alcohol congeners.
Abstract: A series of cymantrene- and cyrhetrene-nucleobase derivatives together with the ferrocene-adenine conjugates have been prepared and characterized. The key step in synthesis of all compounds involved an N1-regioselective Michael addition of the respective nucleobase nucleophile to an in situ generated organometallic acryloyl electrophile reagent. The mechanism of this reaction was examined by DFT calculations. A single crystal X-ray diffraction study of cymantrene-adenine (5) were carried out and revealed that the plane of the adenine and the cyclopentadienyl group are almost perpendicular to each other. The cyclic voltammetry measurements on the cymantrenyl-nucleobases showed irreversible behavior for all compounds which can be explain by a ligand exchange of carbonyls with the donor functionality of the nucleobases. Cymantrene and cyrhetrene ketone nucleobases displayed significant in vitro activity against Trypanosoma brucei a causative parasite of sleeping sickness. They showed no cytotoxicity against human HL-60 cancer cells.
TL;DR: In this paper, the authors reported synthesis of silica nanospheres containing ferrocene-tagged imidazolium acetate (SiO2@Im-Fc[OAc]) as an efficient heterogeneous nanocatalyst for synthesis of naphthopyran derivatives under solvent-free conditions.
Abstract: We report synthesis of silica nanospheres containing ferrocene-tagged imidazolium acetate (SiO2@Im-Fc[OAc]) as efficient heterogeneous nanocatalyst for synthesis of naphthopyran derivatives under solvent-free conditions, based on modification of nano SiO2 by ionic liquid with ferrocene tags and subsequent anion metathesis reaction. The synthesized novel nanocatalyst (SiO2@Im-Fc[OAc]) was systematically characterized using Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and field-emission scanning electron microscopy. The catalytic activity of (SiO2@Im-Fc[OAc]) was tested in one-pot three-component reaction of aromatic aldehydes, malononitrile, and 2-naphthol for facile synthesis of naphthopyran derivatives. To achieve high catalytic efficacy, the effects of various reaction parameters such as temperature, amount of catalyst, type of solvent, etc. were investigated. Furthermore, recovery and reuse of the nanocatalyst several times was demonstrated without appreciable loss in catalytic activity. The presented protocol offers several advantages, including green and ecofriendly nature, operational simplicity, higher yield, and easy recovery and reuse of the nanostructured catalyst. The workup of these very clean reactions involves only recrystallization of the product from ethanol and recovery of the catalyst by filtration.