Synthesis,structure, and fungicidal activity of thia- and aza-ferrocenophanes

Reaction of bridging dicyclopentadienyl disodium E(CH₂COCpNa)₂ (E = S or NPh, Cp = cyclopentadienyl) with FeCl₂ yields thia- and aza-[5]ferrocenophanes E(CH₂COCp)₂Fe [E = S (1) and NPh (2)]. Treatment of C₁₄H₈(CH₂SCH₂COCpNa)₂ (C₁₄H₈ = 9,10-anthracenyl) with FeCl₂ affords dithia-[12]ferrocenophane C₁₄H₈(CH₂SCH₂COCp)₂Fe (3), while similar reaction of C₆H₄(CH₂SCH₂COCpNa)₂ (C₆H₄ = 1,4-phenyl) with FeCl₂ provides a mixture of dithia-[12]ferrocenophane C₆H₄(CH₂SCH₂COCp)₂Fe (4) and tetrathia-[12,12]ferrocenophane [C₆H₄(CH₂SCH₂COCp)₂Fe]₂ (5), which are separated easily by column chromatography. These five compounds were characterized by IR and NMR spectroscopic analyses and the structures of 2 and 3 were further confirmed by single crystal X-ray diffraction. The electrochemical behaviors of 1–4 were investigated by cyclic voltammetry. In addition, their fungicidal activities against Alternaria solani, Cercospora arachidicola, Physalospora piricola, and Botrytis cinerea were tested in vitro.     

Comparative toxicity of [3]ferrocenophane and ferrocene moieties on breast cancer cells

Recent results suggest that [3]ferrocenophane may be an interesting motif in the development of cytotoxic anti-cancer agents. We here report the synthesis of three such compounds based on the 1-[(p-R-phenyl)-phenyl-methylidenyl)]-[3]ferrocenophane skeleton with R = OH, NH₂ and NHC(O)CH₃ substitution on one of the phenyl rings. Cytotoxicity studies show that these compounds are up to four times more powerful against hormone-independent breast cancer cells than their corresponding ferrocene analogs.     

Reaction of 1,1′‐Divinyl Ferrocene with One‐Electron Oxidants: Entry into Functionalised [4]Ferrocenophanes and Observation of an Isotope‐Dependent Chemoselectivity Effect

1,1′‐Divinyl ferrocene ( 2 ) reacts with K₃[Fe(CN)₆] under basic biphasic conditions to give a [4]ferrocenophane ( 4 ) in good yield. Incorporating deuterium labels into the internal positions of the vinyl groups of 2 affects the chemoselectivity of the reaction; thus under identical reaction conditions, [D₂]‐ 2 reacts to provide a diol‐functionalised [4]ferrocenophane, [D₂]‐D /L ‐ 6 in addition to the expected keto‐alcohol, [D₁]‐ 4 . Variants on this one‐electron oxidative cyclisation methodology can be used to give other [4]ferrocenophanes; thus, the reaction of 2 with CuCl₂ in MeOH or iPrOH leads to dialkoxy [4]ferrocenophanes 19 and 20 , respectively, whereas the reaction of 2 with benzyl carbamate in the presence of tBuOCl gives a bis(carbamate)[4]ferrocenophane, 21 . Mechanisms to account for the formation of the products, the stereoselectivity, and the unusual isotope‐dependent chemoselectivity in the reaction of 2 and [D₂]‐ 2 with K₃[Fe(CN)₆] are proposed.     

两个大环二茂铁环蕃的合成与晶体结构

本文合成了2个大环硒杂二茂铁环蕃,1,9-二硒杂-5-硫杂[9]二茂铁环蕃(1)和1,9,21,29-四硒杂-5,25-二硫杂[9.9]二茂铁环蕃(2),并应用核磁、质谱、单晶X-射线衍射进行了表征。循环伏安法测得二茂铁的氧化还原半波电位分别为-30(81)mV(1)和42(67)mV(2)。     

Synthesis of a distanna [2]ferrocenophane and reactivity of [2]ferrocenophanes towards elemental sulfur and selenium

Here we report the synthesis and crystal structure of a new [2]ferrocenophane [Fe(η⁵-C₅H₄)₂(SntBu₂)₂] with a sterically demanding distannanediyl bridge. The reactivity of the title compound towards selected main group elements was examined and in addition, this reactivity pattern was established for the related diboranediyl bridged [2]ferrocenophane [Fe(η⁵-C₅H₄)₂(BNMe₂)₂].     

Synthesis, structure and properties of the macrocyclic ferrocenophanes with cyclopentadienyl ligands tethered by oligo(ethylene glycol) chain

Cyclization reactions of Fe{C₅H₄OCH₂(CH₂OCH₂)_nCH₂OTs}₂ (n = 1, 2) with C₆H₄-1,2-(OH)₂, C₆H₄-1,3-(OH)₂, and Fe(C₅H₄OAc)₂ under basic conditions yield the corresponding macrocyclic 1,1′-ferrocenophanes. The ferrocenophane having a pyrido-crown ether structure was also synthesized. These ferrocenophanes were characterized by X-ray crystallography and NMR spectroscopy. Cyclic voltammograms of the ferrocenophanes exhibited reversible redox peaks assigned to the oxidation and reduction of the ferrocene unit. The macrocyclic pyrido-containing ferrocenophane forms pseudorotaxane with [NH₂{(CH₂)₉Me}₂]BARF (BARF = B{C₆H₃-3,5-(CF₃)₂}₄) in CDCl₃.     

Structure and properties of protonated N-alkyl-2-aza[3]ferrocenophanes

Protonation of N-alkyl-2-aza[3]ferrocenophanes by HCl and NH₄PF₆ affords hexafluorophosphate salts having a trialkylammonium group. Structures of the protonated and unprotonated N-(p-methylbezyl)-2-aza[3]ferrocenophanes were determined by X-ray crystallography. Variable temperature ¹³C{¹H} NMR spectra of the N-protonated N-hexyl-2-aza[3]ferrocenophane revealed inversion of the nitrogen of the 2-aza[3]ferrocenophane on the NMR time scale probably via partial deprotonation of the nitrogen atom. Cyclic voltammograms of the N-protonated compounds exhibited reversible redox peaks at higher potentials than those of the corresponding neutral ferrocenophanes.     

Organometallic compounds: XXXVII. Bridge rearrangements of multibridged ferrocenophanes in the presence of aluminum chloride

Two bridge-rearrangement reactions with AlCl₃ have been found in the cyclization of [4](1,1′)[3](2,2′)[4](4,4′)ferrocenophanebutanoic acids (XIb and XIIb) and in the Friedel-Crafts acylation of [4](1,1′)-α-oxo[3](2,2′)[4](4,4′)ferrocenophane(I). The cyclization of XIb and XIIb with ClCO₂Et/NEt₃/AlCl₃ gives no tetrabridged ferrocenophane but three dibridged ferrocenophanes (XVII, XVIII and XIX) each containing two six-membered condensed-rings which are formed via homoannular cyclization of the side chains followed by rearrangement of the existing tetramethylene bridges. Various multibridged ferrocenophanes were treated with AlCl₃ to account for the reaction mode in the rearrangement of I, and evidence for selective acyl migration of the oxotrimethylene bridge to the other cyclopentadienyl ring has been obtained.     

Hexamethyl-1,2,3-tristanna-[3]ferrocenophane – Molecular Structure and Cleavage of the Tin–Tin Bonds by Iodine,Sulfur, Selenium,and Tellurium

Hexamethyl-1,2,3-tristanna-[3]ferrocenophane ( 1 ) was prepared by the reaction of 1,1′-bis(dimethylstannyl)ferrocene ( 3 ) with bis(diethylamino)dimethylstannane. The molecular structure of 1 was determined by X-ray crystallography. The monoclinic unit cell (space group P2₁/c; a = 18.659(4), b = 17.311(3), c = 13.719(3) Å; β = 111.02(3)°) contains two independent molecules which differ slightly in their conformation. The cyclopentadienyl rings are almost parallel, but the positions of the substituted carbon atoms are twisted by τ £ 62° with respect to the ecliptic positions. The reactivity of 1 towards iodine and chalcogens E (E = S, Se, Te) was studied. Iodine reacts to give 1,1′-bis[iodo(dimethyl)stannyl]ferrocene ( 6 ) and dimethyltin diiodide. In the case of the chalcogens, the detectable and isolated products are 1,3-distanna-2-chalcogena-[3]ferrocenophanes (E = S ( 7 ), Se ( 8 ), Te ( 9 )) in addition to trimeric dimethyltin chalcogenides, (Me₂SnE)₃. Crystals suitable for X-ray structural analysis could be obtained of 1,3-distanna-2-thia-[3]ferrocenophane ( 7 ); the triclinic unit cell (space group P 1) has the dimensions a = 6.538(2), b = 9.013(2), c = 15.442(2) Å; α = 92.15(2), β = 91.89(2), γ = 109.43(2)°. The molecular structures of 1 and 7 are compared with those of other 1,3-distanna-[3]ferrocenophanes. All compounds were studied by NMR spectroscopy (¹H, ¹³C, ⁷⁷Se, ¹¹⁹Sn and ¹²⁵Te NMR) in order to establish the presence of the [3]ferrocenophanes 7 – 9 and of the cycles (Me₂SnE)₃ in solution.     

Electrospun nanofibers of polyferrocenylsilanes with different substituents at silicon

The strained silicon-bridged [1]ferrocenophane Fe(η-C₅H₄)₂SiBuMe was prepared via a facile chloride substitution reaction at the bridging atom of a readily available SiMeCl-bridged [1]ferrocenophane precursor. Thermal ring-opening polymerization of Fe(η-C₅H₄)₂SiBuMe and Fe(η-C₅H₄)₂SiMe₂ afforded polyferrocenyldimethylsilane (PFDMS) and polyferrocenylbutylmethylsilane (PFBMS), respectively. Polyferrocenylsilane nanofibers were fabricated by electrospinning polymer solutions in 90 wt% tetrahydrofuran and 10 wt% N,N-dimethylformamide at room temperature. The effect of processing parameters such as concentration of polyferrocenylsilanes solution, applied voltage, and working distance on the diameter and morphology of resulting nanofibers were investigated. Electron diffraction patterns from polymer nanofibers revealed that PFS fibers exhibit different orientation owing to variance of the side groups at silicon.     

Supramolecular Organometallic Polymer Chemistry: Self-Assembly of a Novel Poly(ferrocene)-b-polysiloxane-b-poly(ferrocene) Triblock Copolymer in Solution

Micelles with unprecedented flowerlike arrangements of the poly(ferrocene) cores (shown in the TEM image) are among the supramolecular architectures generated in the self-assembly of a novel organometallic triblock copolymer from silicon-bridged [1]ferrocenophane monomers and [Me₂SiO]₃ in hexane, a solvent selective for the central polysiloxane block.     

[5]Ferrocenophane based ligands for stereoselective Rh-catalyzed hydrogenation and Cu-catalyzed Michael addition

A series of homochiral [5]ferrocenophane based N/P, N/S, N/Se, Se/P and P/P ligands was prepared from (R)-N,N-dimethylamino[5]ferrocenophane. These ligands were tested in the Rh-catalyzed hydrogenation of dimethyl itaconate and in Cu-catalyzed Michael addition of Et₂Zn to cyclohex-2-enone. The best results in terms of conversion and enantioselectivity in the Rh-catalyzed hydrogenation provided bis(diphenylphosphine) ligand 2h (100% conversion and 95% ee) and aminophosphine 2a in the Cu-catalyzed conjugate addition (100% conversion 84% ee). The enantioselectivity of the Rh-catalyzed hydrogenation of methyl 2-acetamidoacrylate was lower (41% ee).     

Syntheses and structural characterization of some mono- and di-p-nitrophenyl[3]ferrocenophanes: X-ray structure of [3]ferrocenophane, 3-p-nitrophenyl[3]ferrocenophane, and 3,4′-bis-(p-nitrophenyl)[3]ferrocenophane; DFT calculations on ferrocene derivatives

[3]Ferrocenophane (3a) reacts in a Gomberg reaction with diazotized p-nitroaniline to give a mixture of mono- and di-substituted products. The isomeric pairs of 3- and 2-(p-nitrophenyl)[3]ferrocenophanes (4 and 5), as well as 3,4′- and 3,4-bis-(p-nitrophenyl)[3]ferrocenophanes (6 and 7) were separated from the mixture by column chromatography on Al₂O₃ and characterized by means of mass, IR, UV, ¹H-NMR spectroscopy, and by X-ray analysis (4 and 6). PM3/tm and density functional theoretical calculations on ferrocene (1) and ferrocenophane derivatives are reported. A refined X-ray structure determination of [3]ferrocenophane (3a) is given.     

Mössbauer spectroscopic studies on the products of [2]ferrocenophane with CF3COOH,CCl3COOH,CF3SO3H,CH3COOH and SbCl5

Reaction products of [2]ferrocenophane with CF₃COOH, CCl₃COOH, CF₃SO₃H and SbCl₅ were prepared. Mössbauer spectroscopic data and magnetic susceptibility measurements suggest the bond formation of Fe–H⁺ and Fe–Cl⁺, in which iron atoms are in a high-spin Fe/II/state.     

Synthesis and Structure of a Carbamato‐bridgded Digallyl‐ferrocenophane – Fixation of Carbon Dioxide with Aminogallanes

By reaction of tmp₂GaCl (tmp = 2,2,6,6‐tetramethylpiperidino) ( 1 ) with dilithioferrocene the 1,1′‐digallylferrocene [{Fe(η⁵‐C₅H₄)₂}(tmp₂Ga)₂] ( 2 ) was prepared. 2 reacted with CO₂ to afford the ferrocenophane [Fe{η⁵‐C₅H₄‐Ga(O₂Ctmp)(μ²‐O₂Ctmp)}₂] ( 3 ). Here, an eight‐membered Ga(OCO)₂Ga‐Ring is the bridge in the ferrocenophane structure. The gallium carbamates [Me₂GaO₂Ctmp]₂ ( 5 ), and tmp₂Ga(η²‐O₂Ctmp) ( 7 ) show structural features embedded in 3 . The compounds were fully characterized by NMR, cyclovoltammetry and single crystal X‐ray structure analysis.     

Organometallic Polyelectrolytes: Synthesis,Characterization and Layer‐By‐Layer Deposition of Cationic Poly(ferrocenyl(3‐ammoniumpropyl)‐methylsilane)

The water soluble poly(ferrocenylsilane) polycation, poly(ferrocenyl(3‐ammoniumpropyl)methylsilane), was synthesized by transition metal‐catalyzed ring‐opening polymerization of the novel [1]ferrocenophane Fe(η‐C₅H₄)₂SiCH₃(CH₂)₃Cl and by subsequent side group modification. Amination of the chloropropyl moieties using potassium 1,1,3,3‐tetramethyldisilazide followed by acidic hydrolysis produced the polycation. The polycation was employed together with poly(sodium vinylsulfonate) in the electrostatic layer‐by‐layer self‐assembly process to form organometallic multilayers on quartz. The multilayer fabrication process was monitored using UV/Vis absorption spectroscopy and XPS.     

Organometallic compounds : XXXIV. Bridge enlargement reaction of multibridged ferrocenophanes with diazomethane and syntheses of some ferrocenophanes with tetramethylene bridges by application of the reaction

Bridge enlargement reactions of α-oxo [3] ferrocenophane derivatives with diazomethane in the presence of methanol or BF₃·OEt₂ have been studied. Some new multibridge ferrocenophanes with tetramethylene bridges have been synthesized by application of the enlargement reaction.     

Bisglycine-substituted ferrocene conjugates

The solid state structures of three bissubstituted glycine ferrocene conjugates are described allowing a direct comparison of the structural parameters. Whereas the fully protected glycine ester Fc(Gly-OEt)₂ adopts a 1,3′-conformation leading exclusively to intermolecular H-bond formation, the free acid Fc(Gly-OH)₂ adopts the more compact 1,3′-comformation with intramolecular H-bonding. The same intramolecular H-bonding pattern is adopted by the glycine ferrocenophane Fc(Gly-CSA)₂.     

Synthesis, computational modelling and liquid crystalline properties of some [3]ferrocenophane-containing Schiff’s bases and β-aminovinylketone: Molecular geometry-phase behaviour relationship

Rotationally fixed [3]ferrocenophane extends the variety of possible molecular geometries in its derivatives in comparison with unbridged ferrocenes. In this respect molecular geometry-liquid crystalline properties relationship studies in [3]ferrocenophane mesogens are of considerable interest. Different positional isomers of mono- and di-substituted [3]ferrocenophanes which are obtained by incorporating one or two promesogenic building blocks into the cyclopentadienyl rings are reported in this article. A series of mono-substituted [3]ferrocenophane-containing Schiff’s bases was synthesized by condensing isomeric p-aminophenyl [3]ferrocenophanes with appropriate aldehydes. Isomers of di-substituted [3]ferrocenophane amines gave rise to a series of azomethines with two promesogenic substituents in the cyclopentadienyl rings. Besides, a β-enaminoketone was prepared from 3-(p-aminophenyl)[3]ferrocenophane. Nematic and smectic mesophases were observed in the synthesized compounds under a polarizing optical microscope. The [3]ferrocenophane-containing β-enaminoketone showed complex mesomorphic behaviour connected with occurrence of the keto-enamine and imino-enol tautomeric equilibrium in this compound. On the base of computational models obtained by semi-empirical quantum chemistry calculations the molecular geometry-phase behaviour relationships were examined. It was demonstrated that mesomorphism of [3]ferocenophane azomethines depends on the spatial orientation of the substituents with respect to the propanediyl bridge in a case of mono-, and as well as to each other in a case of di-substituted derivatives.     

Unusual carbamate-directed CH-activation at an annulated ferrocenophane framework

The tetrahydroazepine-annulated [3]ferrocenophane carbamate (4) was synthesized by two different linear routes starting from the readily available α-dimethylamino[3]ferrocenophane-ortho-carbaldehyde rac-6. The carbamate directed lithiation of 4 resulted in a selective attack at a (Cp)C-H bond at the higher substituted "lower" [3]ferrocenophane Cp-ring to eventually yield the respective ester (18) after treatment with ClCO(2)Me.