Ferroceneboronic Acid Research Articles

Disposable Sandwich‐type Electrochemical Sensor for Selective Detection of Glucose Based on Boronate Affinity

AbstractA disposable sandwich‐type electrochemical sensor for selective detection of glucose was established. The primary receptor, 3‐aminophenylboronic acid was grafted covalently onto the surface of screen‐printed carbon electrodes through an in situ‐generated diazo‐reaction. Glucose was first captured by boronic acid group on the electrode, followed by captureing an electroactive ferroceneboronic acid (FcBA) as the secondary receptor to form bidentate glucose‐boronic complex. Electrochemical impedance spectroscopy was applied to characterize the construction of sandwich‐type disposable sensor. In the sandwich assay, current response of captured FcBA on the electrode was dependent on the concentration of glucose. The sandwich assay showed higher selectivity for glucose than that for fructose, mannose, galactose and other electroactive interferences including uric acid, ascorbic acid and dopamine, and exhibited a dynamic concentration range of glucose from 0.5 to 20.0 mmol L−1. The disposable sensor demonstrated a good reproducibility with 2.2 % relative standard deviation (RSD). In addition, the disposable glucose sensor was used in detection of the trace glucose in the clinical urine samples.

Synthesis of amphiphilic block copolymers containing ferrocene–boronic acid and their micellization, redox-responsive properties and glucose sensing

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A sensitive signal-off electrogenerated chemiluminescence biosensing method for the discrimination of DNA hydroxymethylation based on glycosylation modification and signal quenching from ferroceneboronic acid

In this study, a new and sensitive signal-off electrogenerated chemiluminescence (ECL) biosensing method for the quantification of 5-hydroxymethylcytosine in DNA (5-hmC-DNA) was developed. The method achieved simple and sensitive detection of 5-hmC-DNA based on the glycosylation of 5-hmC, combining both the amplification function of gold nanoparticles (AuNPs) and the high quenching efficiency of the tris(2, 2′-ripyridine) dichlororuthenium(II) (Ru(bpy)32+)-ferrocene (Fc) system. First, the electrode modified with a mixture of Nafion and AuNPs was utilized as the platform for electrostatically adsorbing Ru(bpy)32+(an ECL-emitting species) and assembling 5-hmC-DNA. The 5-hmC-DNA was glycosylated by T4 β-glucosyltransferase, yielding β-glucosyl-5-hydroxymethyl-cytosine in DNA (5-ghmC-DNA). Finally, quencher-FcBA was further covalently bound to 5-ghmC-DNA through formation of boronate ester covalent bonds between boronic acid and cis-diols of 5-ghmC, resulting in a decrease in ECL intensity. The results indicated that the decreased ECL intensity was directly linear to the concentration of 5-hmC-DNA in the range from 1.0×10−8 to 5.0×10–11M with a low detection limit of 1.63×10–11M. In addition, this ECL method was demonstrated to be useful for the quantification of 5-hmC in clinical serum samples. Moreover, the method allowed good discrimination among cytosine (5-C), 5-methylcytosine (5-mC), and 5-hmC in DNA.

Two-step synthesis of ferrocenyl esters of vanillic acid

Successive reactions of vanillin with aromatic aldehydes at the phenol group and ferroceneboronic acid at the carbonyl group catalyzed with various N-heterocyclic carbenes afforded the corresponding ferrocenyl esters. In these reactions copper(II) sulfate, cinnamic aldehyde, and air oxygen act as oxidants. The resulting ferrocenyl esters of vanillic acid were tested for cytotoxicity.

Multimetallic Gold–Iron Compounds Based on Aurated Ferrocenes

A family of aurated ferrocenes was prepared by a transmetallation reaction using ferroceneboronic acid derivatives. With this method, multimetallic ferrocenyl complexes [FcAu(PPh3)] {Fc = (η5‐C5H4)FeCp} and [(µ‐P‐P)(AuFc)2] {P‐P = dppe, dppf}, as well as 1,1′‐diaurated ferrocenes [Fe(η5‐C5H4AuPPh3)2] and [Fe{(η5‐C5H4Au)}2(µ‐P‐P)] {P‐P = dppe, dppf}, were obtained in high yields as air‐stable orange materials. The compounds were characterised by spectroscopic methods, cyclic voltammetry and single‐crystal X‐ray diffraction. The reactivity of the dinuclear gold(I) complex in oxidative addition reactions is also reported.

Synthesis and Structure of Ferrocenol Esters

N-Heterocyclic carbene-catalyzed oxidative esterification of ferroceneboronic acid by aromatic and heteroaromatic aldehydes affords the new ferrocenol hetaryl and aryl esters 1 - 4, 6 - 8 and 9 - 11. The reaction takes place under mild conditions. The X-ray crystal structure of ferrocenyl esters 3, 6, 11 was determined.

Interaction of ferroceneboronic acid with diols at aqueous and non-aqueous conditions - signalling and binding abilities of an electrochemical probe for saccharides

Ferroceneboronic acid (FcBA) was employed as a model compound for clarification of binding and signalling properties of molecular probe for saccharides. As the simplest electrochemically active boronic acid, its interactions with diverse diols were studied in homogeneous phase under aqueous and non-aqueous conditions. The FcBA-diol system was examined by cyclic voltammetry resulting in two redox pairs corresponding to free and bound forms of FcBA. Redox potential of the bound form of FcBA was shifted in the cathodic direction in aqueous conditions due to coordination of the hydroxyl group to the boron atom. Oppositely, the anodic shift of the redox potential was observed upon the interaction of FcBA with diols in non-aqueous solvents. The binding properties and signalling mechanism of electrochemically active boronic acids were deduced and the assumptions resulting from the electrochemical behaviour were confirmed by 1H and 11B NMR spectroscopies. The binding constants of the tested diols in aqueous and non-aqueous media were determined and compared.

Electrochemical determination of catechin, protocatechuic acid, and L-lactic acid based on voltammetric response of ferroceneboronic acid.

An electrochemical technique for the determination of catechin, protocatechuic acid, and L-lactic acid has been developed using ferroceneboronic acid (FBA) as an electrochemical probe. The principle is based on thechanges in voltammograms of FBA associated with selective binding of the analytes to FBA. A cyclic voltammogram and a differential pulse voltammogram (DPV) of FBA were recorded on a glassy carbon electrode in the presence of the analytes. The oxidation or reduction peak currents of FBA were decreased in the presence of the analytes, depending on their concentrations. The DPV measurements provided useful calibration graphs in the concentration range of 0.5-4.0 x 10(-3) M catechin, 0.1-1.2 x 10(-5) M protocatechuic acid, and 0.5-40 x 10(-5) M L-lactic acid. The proposed method was successfully applied to the analysis of catechin in abdominal pain water medicine.

Reaction of boronic acids with tetrafluoroborate? It depends on the acidity

After electrochemical or chemical oxidation of ferroceneboronic acid, the resulting ferriceniumboronic acid is found to react with tetrafluoborate to form ferricenyltrifluoborate. This reaction with a common electrolyte can be extended to other boronic acids that possess a sufficiently low pKa (<7).

Electrochemical biosensors based on ferroceneboronic Acid and its derivatives: a review.

We review recent progress in the development of electrochemical biosensors based on ferroceneboronic acid (FcBA) and ferrocene (Fc)-modified boronic acids. These compounds can be used to construct electrochemical biosensors because they consist of a binding site (i.e., a boronic acid moiety) and an electrochemically active part (i.e., an Fc residue). By taking advantage of the unique properties of FcBA and its derivatives, electrochemical sensors sensitive to sugars, glycated hemoglobin (HbA1c), fluoride (F−) ions, and so forth have been widely studied. FcBA-based sugar sensors rely on the selective binding of FcBA to 1,2- or 1,3-diol residues of sugars through the formation of cyclic boronate ester bonds. The redox properties of FcBA-sugar adduct differ from those of free FcBA, which forms the basis of the electrochemical determination of sugars. Thus, non-enzymatic glucose sensors are now being actively studied using FcBA and Fc-modified boronic acids as redox markers. Using a similar principle, HbA1c can be detected by FcBA-based electrochemical systems because it contains hydrocarbon chains on the polypeptide chain. HbA1c sensors are useful for monitoring blood glucose levels over the preceding 8–12 weeks. In addition, FcBA and Fc-modified boronic acids have been used for the detection of F− ions due to the selective binding of boronic acid to F− ions. F−-ion sensors may be useful alternatives to conventional ion-selective electrodes sensitive to F− ion. Furthermore, FcBA derivatives have been studied to construct lectin; steroids; nucleotides; salicylic acid; and bacteria sensors. One of the limitations of FcBA-based sensors comes from the fact that FcBA derivatives are added in sample solutions as reagents. FcBA derivatives should be immobilized on the surface of electrodes for developing reagentless sensors.

Electrochemical displacement sensor based on ferrocene boronic acid tracer and immobilized glycan for saccharide binding proteins and E. coli

Pathogens such as viruses and bacteria use their envelope proteins and their adhesin lectins to recognize the glycan residues presented on the cell surface of the target tissues. This principle of recognition is used in a new electrochemical displacement sensor for the protein concanavalin A (ConA). A gold electrode was first modified with a self-assembled monolayer of a thiolated mannose/OEG conjugate and a ferrocene boroxol derivative was pre-assembled as reporter molecule onto the mannose surface. The novel tracer molecule based on a 2-hydroxymethyl phenyl boronic acid derivative binds even at neutral pH to the saccharides which could expand the application towards biological samples (i.e., urine and feces). Upon the binding of ConA, the tracer was displaced and washed away from the sensor surface leading to a decrease in the electrochemical signal. Using square wave voltammetry (SWV), the concentration of ConA in the sample solution could be determined in the dynamic concentration range established from 38nmolL−1 to 5.76µmolL−1 with a reproducible detection limit of 1µgmL−1 (38nmolL−1) based on the signal-to-noise ratio (S/N=3) with fast response of 15min. The new reporter molecule showed a reduced non-specific displacement by BSA and ribonuclease A. The sensor was also successfully transferred to the first proof of principle for the detection of Escherichia coli exhibiting a detection limit of approximately 6×102cells/mL. Specificity of the displacement by target protein ConA and E. coli was demonstrated since the control proteins (i.e., BSA and RNaseA) and the control E. coli strain, which lack of type 1 fimbriae, were ineffective.

Investigation of the Interaction between Ferroceneboronic Acid and Sugars and Its Application in Probing of Enzyme Activity

Investigation of the Interaction between Ferroceneboronic Acid and Sugars and Its Application in Probing of Enzyme Activity

Carbohydrate‐Based Ferrocenyl Boronate Esters: Synthesis, Characterization, Crystal Structures, and Antibacterial Activity

AbstractA set of ferrocenyl boronate esters based on carbohydrate scaffolds was designed and synthesized efficiently by the reaction of ferroceneboronic acid with protected sugar diols derived from D‐xylose, L‐sorbose, and D‐mannitol in good yield. These compounds identified as 1,2‐O‐isopropylidene‐α‐D‐xylofuranose‐3,5‐ferrocenyl boronate (3a), 1,2‐O‐cyclohexylidene‐α‐D‐xylofuranose‐3,5‐ferrocenyl boronate (3b), 1‐O‐benzyl‐2,3‐O‐isopropylidene‐α‐L‐sorbofuranose‐4,6‐ferrocenyl boronate (3c), 1,2:5,6‐di‐O‐isopropylidene‐D‐mannitol‐3,4‐ferrocenyl boronate (3d), and 1,2:5,6‐di‐O‐cyclohexylidene‐D‐mannitol‐3,4‐ferrocenyl boronate (3e), were isolated as air‐ and moisture‐stable orange/yellow crystalline solids. All of the six‐membered (3a, 3b, and 3c) and five‐membered (3d and 3e) cyclic boronate esters were fully characterized by IR, multinuclear NMR (1H, 13C and 11B), and UV/Vis spectroscopy, and also elemental analysis. The electrochemical behavior of the synthesized ferrocenyl boronate esters containing carbohydrates was investigated. Furthermore, the structures of 3a and 3c were unambiguously established by single‐crystal X‐ray diffraction analysis. The compounds have been screened for in vitro antibacterial activity against various Gram‐positive and Gram‐negative bacteria. They exhibited moderate to good inhibitory activity against the tested bacterial strains in comparison with standard drugs.

A Simple and Rapid Method for Probing of Isomerization of Glucose to Fructose with Ferroceneboronic Acid

A Simple and Rapid Method for Probing of Isomerization of Glucose to Fructose with Ferroceneboronic Acid

3,5-Diferrocenylpyridine: Synthesis, characterisation, palladium(II) dichloride complex and electrochemistry

3,5-Diferrocenylpyridine was synthesised from 3,5-dibromopyridine and ferroceneboronic acid, in respectable yield (48%), using a microwave-enhanced Suzuki cross-coupling reaction. This novel ligand and its palladium(II) dichloride complex have been fully characterised using elemental analysis, HR–ESI-MS, IR, UV and NMR spectroscopy. Additionally, the molecular structures of 3,5-diferrocenylpyridine and [Pd(3,5-diferrocenylpyridine)2Cl2] were confirmed by X-ray crystallography. A comprehensive study of the electrochemistry of 3-ferrocenylpyridine, 3,5-diferrocenylpyridine and their palladium(II) dichloride complexes was performed using traditional hexafluorophosphate and weakly-coordinating fluorinated aryl borate anions. Electronic communication between the two proximal ferrocenyl centres of 3,5-diferrocenylpyridine and its palladium complex is only observed when the weakly-coordinating fluorinated aryl borate anions are used as the supporting electrolyte.

Voltammetric Determination of Salicylic Acid and Derivatives Based on Ferroceneboronic Acid

Voltammetric Determination of Salicylic Acid and Derivatives Based on Ferroceneboronic Acid

Ferroceneboronic acid for the electrochemical probing of interactions involving sugars

Ferroceneboronic acid (FcBA) was used as a redox-active probe suitable for monitoring of diol–boronate interactions. Voltammetric and amperometric measurements allowed to detect FcBA forms – free and bound in the boronate complex. In this way, the complexation interaction was studied for a set of saccharide molecules as model diols and the corresponding affinity equilibrium constants were determined. A shift of the peak potential on voltammograms accompanying formation of the boronate complex with FcBA was proposed as a probe for electrochemical characterization of surface-confined diol-containing structures. The model experiments were carried out using sorbitol- and 1,6-hexandiol-modified polyepichlorhydrin conjugates deposited on the electrodes; the former compound was able to form the boronate complex while no change of the peak potential for the latter conjugate was observed. This approach seems promising for artificial bioelectronic affinity receptors and technology of reagentless biosensors where the binding interaction directly stimulates a measurable electrochemical event.

Voltammetric response of ferroceneboronic acid to diol and phenolic compounds as possible pollutants

A voltammetric determination of possible organic pollutants such as diol and phenolic compounds in water was studied using ferroceneboronic acid (FBA) as a redox-active marker. A cyclic voltammogram of FBA exhibited a pair of oxidation and reduction peaks at 230 and 170 mV at pH 7.0, respectively, while another pair of redox peaks was observed in the presence of diol or phenolic compounds tested. The results were rationalized based on the formation of boronate esters of FBA with the added compounds. The changes in the redox peak currents were dependent on the concentration of the additives, suggesting a usefulness of FBA in the electrochemical determination of these compounds in water.

A Nonenzymatic Amperometric Method for Fructosyl‐Valine Sensing Using Ferroceneboronic Acid

AbstractFructosyl valine (Fru‐Val) is a glycosylated component of hemoglobin (HbA1c) that can serve as a diagnostic target for type 2 diabetes. While average blood glucose levels fluctuate significantly, the more stable levels of HbA1c can serve as a better long‐term diagnostic marker. Here a diagnostic system, incorporating an amperometric method, for detecting Fru‐Val (at +0.1 V vs. Ag/AgCl), using ferrocene boronic acid (FcBA) is presented. FcBA can complex diols, and has easily detectable redox properties. The boronic acid group in FcBA mediates complexation, while the Fe(II)/Fe(III) couple serves as a transducer. The diagnostic system, based on a miniaturized bare glassy carbon paste electrode (GCPE), has a fast response time.

ChemInform Abstract: Convenient and Efficient Palladium‐Catalyzed Coupling Reaction Between Ferroceneboronic Acid and Organic Triflates.

A simple and efficient palladium (Pd)–catalyzed Suzuki cross-coupling reaction between ferroceneboronic acid and organic triflates for the preparation of monosubstituted ferrocene derivatives has been developed. A systematic study of various solvents, bases, and catalysts revealed that the combination of Pd(PPh3)4 (0.025 equiv) and K3PO4 (2 equiv) in refluxing dioxane gave reproducible and excellent yields of the coupling products. The reaction could be applied to a wide variety of aryl and vinyl triflates in good to excellent yields, and the electronic and steric effects were observed for ortho-, meta-, and para-substituents of aryl triflates.