Ferrocenedicarboxylic Acid Research Articles

Assemblies of multiply bonded [Re2]n+ cores possessing bond orders of 3 or 3.5 that are linked by dicarboxylate bridges

An earlier study describing the exchange of the μ-acetato ligands of Re2(μ-O2CCH3)Cl4(μ-dppm)2 (1) and cis-Re2(μ-O2CCH3)2Cl2(μ-dppm)2 (2) by dicarboxylic acids has been expanded to include reactions with the monocarboxylic acid isonicotinic acid, and the dicarboxylic acids adipic acid, 4,4′-biphenyldicarboxylic acid, fumaric acid, trans-1,4-cyclohexanedicarboxylic acid and 1,1′-ferrocenedicarboxylic acid. Further examples of complexes that are “dimers-of-dimers” and triangular supramolecular assemblies involving retention of the basic electronic and molecular structures of the dirhenium units present in 1 and 2 have been obtained. In addition, the dirhenium complexes Re2(μ-O2CC6H4N)Cl4(μ-dppm)2 (7) and cis-Re2(μ-O2C6H10CO2Et)2Cl2(μ-dppm)2 (11) have been isolated, as well as the trimetallic complex cis-Re2Cl2(μ-dppm)2[(μ-O2CC5H4)2Fe] (14) that is formed from the reaction of 2 with (C5H4CO2H)2Fe. The crystal structures of 7, 11 and 14 are reported.

Characterization of Indium−Tin Oxide Interfaces Using X-ray Photoelectron Spectroscopy and Redox Processes of a Chemisorbed Probe Molecule: Effect of Surface Pretreatment Conditions

Surface characterization of indium−tin oxide (ITO) thin films has been carried out with monochromatic X-ray photoelectron spectroscopy (XPS) following various solution pretreatments, RF air plasma etching or high-vacuum argon-ion sputtering. Commercially available ITO films show high concentrations of hydrolyzed oxides and oxy-hydroxides in the near-surface region, along with stoichiometric oxide (In2O3, SnO2) and variable levels of oxygen defect sites. XPS revealed that solution and vacuum treatments changed both the relative surface coverage of the hydroxides and, to a lesser extent, the concentration of oxide defect sites in the near-surface region. These pretreatments have a significant effect on both the coverage and electron-transfer rates for chemisorbed ferrocene dicarboxylic acid (Fc(COOH)2), with the air-plasma-etched ITO showing the highest surface coverage of Fc(COOH)2 and an RCA treatment showing the highest electron-transfer rates.

Efficient synthesis of unsymmetrically disubstituted ferrocenes: towards electrochemical dipeptide-Fc-biosensors

Unsymmetrically disubstituted ferrocenes ( 1a , 1b ), electrochemical dipeptide-Fc-biosensors, were synthesized by a straightforward synthetic method from 1,1′-ferrocenedicarboxylic acid. In addition, an efficient solution synthesis of pentapeptide ( 2 ) was reported.

Synthesis of planar chiral ferrocene dicarboxylic acids using a sugar derivative as a resolution tool

The synthesis of planar chiral ferrocene dicarboxylic acids has been accomplished via diastereoselective esterification at the 2- and 3-positions with (+)-(4,6-O-benzylidene)methyl-α-d-glucopyranoside.

Synthesis of a Large Organometallic Macrocycle Comprising Four Ga−Ga Bonds and Four Bridging Ferrocene Dicarboxylato Ligands

The reaction of tetrakis[bis(trimethylsilyl)methyl]digallane(4), 1, with 1,1‘-ferrocenedicarboxylic acid afforded orange-red crystals of the macrocyclic compound 2 in a yield of 84%. 2 contains a large 32-atom heterocycle, which comprises four Ga−Ga single bonds bridged by four 1,1‘-ferrocenedicarboxylato ligands. The largest diameter of the molecule is about 2.5 nm. The redox-active Ga−Ga sites and ferrocene iron centers are all oxidized irreversibly within a narrow potential range.

Electrospray ionization mass spectrometric analysis of self-assembled 1,1′-ferrocenedicarboxylic acid

Self-assembly of 1,1′-ferrocenedicarboxylic acid in solution was detected by electrospray mass spectrometry (ESI-MS). The ESI mass spectra showed the acid was self-assembled as a cyclic tetramer in methanol and acetonitrile, and the tetramer was found to complex more strongly with the sodium ion than with any other alkali metal ion. The result was supported by semiempirical molecular orbital calculations, which indicate that the tetramer possesses a cyclic structure like a pseudo-crown ether, and its internal diameter is consistent with the diameter of a sodium ion.

Adsorption-induced unusual changes in the electrical conductivity of 1,1′-diacetylferrocene and 1,1′-ferrocenedicarboxylic acid

The effects of adsorption (at 268 K) of ethanol vapor on the electrical conductivity of 1,1′-diacetylferrocene and 1,1′-ferrocenedicarboxylic acid in powder form have been studied by sandwich-type cell technique. A peak has been observed in the current vs. temperature plots in a specific temperature region. The effects of vapor pressure and heating rate on the temperature ( T max) at which the peak appears as well as the magnitude of the peak have been studied in detail. The experiment has indicated two activation energy values of these materials in the vapor-adsorbed state and these values are higher than the values for pure dry state. The unusual changes in the adsorption-induced electrical conductivity of these materials in a specific temperature range are possibly related to the adsorption-induced phase transition in these materials.

Electrical current oscillations in vapor-adsorbed ferrocene derivatives having two substituted groups

Oscillations in electrical current as a function of time have been observed in a specific temperature range in the samples of 1,1′-diacetylferrocene and 1,1′-ferrocenedicarboxylic acid with adsorbed ethanol vapor in a sandwich-type cell. The frequency of current oscillations has been found to decrease with bias voltage and sample temperature and to increase with vapor pressure. The frequency of current oscillations for the mono-group substituted derivatives is higher than the corresponding frequency for the derivatives having two substituted groups. Again, the frequency of oscillations for –COCH 3 group substituted derivatives is higher than the corresponding value for –COOH group substituted derivatives. The observation of current oscillations is possibly associated with some kind of time dependent phase changes, arising from the structural nonrigidity of the molecules, in the solid-ethanol vapor system at the sample surface layer. The “ball-bearing” motion of the cyclopentadienyl rings of ferrocene unit, nature and number of substituted groups, cooperative interaction of the neighboring molecules influence the structural nonrigidity and hence the oscillatory behavior of current. Reasons are given for ruling out other models of current oscillations in semiconductors.

Electrochemically oxidized ferrocenes as catalysts for the chemiluminescence oxidation of luminol

Electrochemically oxidized ferrocene and eleven ferrocene derivatives were investigated as catalysts for the chemiluminescent oxidation of luminol by hydrogen peroxide. The catalytic effect has been related to the redox potential of the ferrocenes. The effect of twelve different buffers with different pKa values and four different electrode materials was also investigated. A combination of ferrocenedicarboxylic acid, bis tris propane buffer and an ITO electrode gave the most intense light emission and eliminated measurable electrogenerated background chemiluminescence. Phenol labelled with ferrocenemonocarboxylic acid via a peptide bond catalyzed more intense chemiluminescence than the parent ferrocene derivative. Results were used to suggest a structure for ferrocene labelled antigens that can be used in competitive immunoassays.

Synthesis and structural characterisation of the zinc carboxylate bis(Ferrocenedicarboxylato) bis(1-methylimidazole_dizinc(II). A structure displaying a bimetallic macrocyclic framework

The synthesis, spectral characterisation and X-ray structure determination of the first zinc(II) ferrocenedicarboxylate [Zn(1,1′-Ferdc)(1-methylimidazole) 2] 2, 1, (1,1′-H 2ferdc = 1,1′-ferrocenedicarboxylic acid) is described. The molecular structure of 1 consists of a centrosymmetric cyclic dimer exhibiting a slightly distorted tetrahedral geometry around the zinc atoms. The ferrocenedicarboxylic acid acts as a syn-bound O,O′-bridging ligand.

Synthesis of aromatic poly(ether ketone)s with ferrocene units in the main chain

AbstractAromatic poly(ether ketone)s with ferrocene units in the main chain were prepared by direct polycondensation of 1,1′‐ferrocenedicarboxylic acid with diphenyl ether or 1,4‐diphenoxybenzene using various catalysts such as trifluoromethanesulfonic acid (triflic acid), a combination of methanesulfonic acid/P2O5 (Eaton's reagent) or a combination of triflic acid/P2O5. Polycondensations at room temperature for 24 h gave poly(arylene ether ketone)s with inherent viscosities up to 40 mL g−1. Monoacylation of diphenyl ether with ferrocenecarboxylic acid was studied in detail in order to show the efficiency of polymer formation employing Eaton's reagent as catalyst and solvent.

Neutral Molecule Receptor Systems Using Ferrocene's “Atomic Ball Bearing” Character as the Flexible Element

Fourteen novel ferrocene derivatives have been designed to serve as receptors for low molecular weight diamines. The compounds that have been prepared and fully characterized possess two ferrocenedicarboxylic acid residues bridged by amide formation in their respective 1‘-positions by 4,4‘-benzidinyl (15), 3,3‘-dimethoxy-4,4‘-benzidinyl (16), 2,7-fluorenyl (17), 3-methoxy-2,7-fluorenyl (18), 4-N-piperazinoanilinyl (19), N,N‘-4,4‘-bipiperdinyl (20), and 4,13-diaza-18-crown-6 (21). In two cases, ferrocenecarboxylic acid was bridged by spacers attached using 1-methylene groups. The bridges in these cases were 4,13-diaza-18-crown-6 (22) and 1,5-diaminoanthraquinone (24). In a single case, ferrocenecarboxylic acid was bridged by 1,5-dicarbonylnaphthalene (25). In one additional case, the bridge was created by formation of an imine followed by hydrogenation, but both compounds (26, 27) proved to be relatively unstable. Attempts to increase solubility afforded the N-ethylated derivative 28 of 15 and the derivative 29 of 27 having carboxamides in the 1‘-positions. A solid state structure of the diethyl ester of 20 confirms the design criteria. Complexation constants were determined in THF-d8 or CDCl3 for combinations of receptors 18, 19, and 20 with 4-aminopyridine, N,N,N‘,N‘-tetramethylethylenediamine, N,N,N‘,N‘-tetramethylpropylenediamine, DABCO, 3-propyladenine, and benzimidazole and were in the range 102−104. The anticipated complexation mechanism for 20 with N,N,N‘,N‘-tetramethylpropylenediamine was confirmed by observation of an NOE between host and guest.

Structural chemistry of organotin ferrocenecarboxylic esters I. Synthesis and spectroscopic studies on dialkyltin esters of ferrocenecarboxylic acid FcCOOH and 1,1′-ferrocenedicarboxylic acid Fc(COOH) 2

Dibutyltin and dioctyltin esters of ferrocenecarboxylic acid and dibutyltin ester of 1,1′-ferrocenedicarboxylic acid have been synthesized and characterized by IR and NMR ( 1H, 13C, 119Sn) spectral data. Spectroscopic data suggest that the esters of ferrocenecarboxylic acid adopt an oxygen-bridge dimer structure mode. The structure features four anisobidentate bridging carboxylate ligands. The ester of 1,1′-ferrocenedicarboxylic acid is five-coordinate monomer in solution.

Synthesis of polymers containing crown ether and ferrocene units

Polyketone containing crown ether and ferrocene moieties was obtained by means of the reaction of 1,1′-ferrocenedicarboxylic acid with dibenzo-18-crown-6 in Eaton's reagent at room temperature. The structure of the polymer was confirmed by various methods.

Ordered conformations in bis(amino acid) derivatives of 1,1′-ferrocenedicarboxylic acid

Two bis(amino acid) derivatives of 1,1′-ferrocenedicarboxylic acid were characterized by IR, 1H NMR and 13C NMR spectroscopy. Each was found to adopt an ordered, intramolecularly hydrogen bonded conformation in CHCl 3.

Organometallic Photoconductors: Dark and Photoconductive Studies on Ferrocene and Some of Its Derivatives

Abstract The dark conduction properties of ferrocenedicarboxylic acid have been studied as a function of voltage at different sample-temperatures by using sandwich type of cell configuration. The analysis of the results was based on the space charge limited conduction (SCLC) theory. The trap distribution in this material has been found to be exponential type as was observed in case of ferrocene and ferrocenecarboxylic acid. The dark activation energy (ohmic) of these ferrocene derivatives increases with the gradual substitution of –COOH group in the ferrocene ring system. In contrast to the nonextrinsic nature of ferrocenecarboxylic acid, ferrocenedicarboxylic acid has been observed to be extrinsic, similar to ferrocene. The photoconductivity in these materials was studied as a function of temperature and the intensity of exciting light source. The distribution of traps in these materials has been determined from the intensity dependence of photocurrent and these results have been compared with the results of dark conductivity measurements.

Cyclic voltammetry of ferrocene carboxylic acid cyclodextrin inclusion complexes

The cyclic voltammetry of ferrocene carboxylic acid (FcA −) was studied in the presence of α, β and γ cyclodextrin (CD). CD affects the magnitude of the peak currents and the position of the peak potentials of the ferrocene carboxylic acid system. A model was set up to simulate the effect of CDs on the electrochemistry of the above species, and also to characterise the formation of the inclusion complexes. Formation constants for the complexes were evaluated in aqueous solution by comparing simulated voltammograms and practical results. It is found that the use of peak potentials ( E f, E b) rather than formal potentials of FcA − ( E 0 1′), and the FcA −CD complex ( E 0 2′), in the simulation is more valid in the evaluation of the formation constants. The ability of the CD isomers to form complexes was found to follow the order β > γ > α. A brief study of the interactions of ferrocene dicarboxylic acid with CDs showed no evidence of second sphere complex formation. It was found also that cyclodextrins enhanced the solubility of unsubstituted ferrocene in water.

Addition of ferrocene derivatives to the surface of quantum-confined cadmium sulfide clusters: steady-state and time-resolved photophysical effects

The effect of substituted ferrocene complexes on the surface of quantum-confined (Q) cadmium sulfide clusters in inverse micelles was examined by steady-state and time-resolved photoluminescence (PL) spectroscopy. Addition of (dimethylamino)methylferrocene (DMAMF) to Q-CdS enhanced cluster PL peak areas by 120%, in contrast to the carboxylic acid derivatives ferrocenecarboxylic acid (FCA) and ferrocenedicarboxylic acid (FDCA), which quenched PL by 60% and 80%, respectively

Disposition of Ferrocenes in β- or γ-Cyclodextrin Cavity and Consideration on the Absorption Bands of Ferrocene

Abstract By comparing the induced circular dichroism (ICD) spectrum of 1,4,7,10,13-pentaoxa[13](1,1′)- ferrocenophane, I, in the presence of β-cyclodextrin (β-CDx) with that of ferrocenes (Fcs) in β-CDx or γ-CDx cavity, the disposition of Fcs in the CDxs is determined. Thus, the orientation of Fc in the Fc: β-CDx 1:1 complex and ferrocenecarboxylic acid (FcMA) in β-CDx at pH 2 is considered to be nearly parallel to the molecular axis of β-CDx, while that of Fc in the Fc: γ-CDx 1 : 1 complex, FcMA in β-CDx cavity at pH 9, and FcMA and ferrocenedicarboxylic acid (FcDA) in γ-CDx cavity appears to be close to normal to the molecular axis of the CDx. In addition, based on the ICD spectra, an intense band of Fcs at around 200 nm is assigned as a charge–transfer (CT) transition between the cyclopentadienyl (Cp) rings and iron(II). The advantage of using CDxs for the determination of the polarization direction of absorption bands of chromophore molecules is mentioned in comparison with previous methods.

ChemInform Abstract: Novel Ferrocene Diesters with Liquid‐Crystal Properties.

Abstract1,1'‐Ferrocenedicarboxylic acid dichloride (I) is esterificated with the biphenol monoalkyl ethers (II) to give the diesters (III).