Diphenylboronic Acid Research Articles

Crosslinking of poly(ethylene-co-vinyl alcohol) with diphenylboronic acid of tetraphenylethene enables reprocessing, shape recovery and photoluminescence

A novel diphenylboronic acid carrying tetraphenylethene moiety (BO-TPE-BO) was synthesized and used to crosslink poly(ethylene-co-vinyl alcohol) (EVOH). The crosslinking reaction occurred between 1,3-diol structural units of EVOH and diphenylboronic acid groups of BO-TPE-BO. The crosslinking densities increased with raising the contents of BO-TPE-BO. Owing to the crosslinking, the thermomechanical properties were significantly improved in terms of glass transition temperatures (Tg's), Young's moduli and tensile strengths. More importantly, the EVOH-TPE networks can be reprocessed (or recycled) via the dynamic exchange of boronic ester bonds. In addition, the EVOH-TPE networks can display the shape memory properties. Through the dynamic exchange of boronic ester bonds, the original shapes of the shape memory polymers were reconfigurable. Thanks to the introduction of tetraphenylethene moieties, the EVOH-TPE networks can additionally display the photoluminescent properties. It was found that the photoluminescent behavior was quite dependent on the crystallinity and the contents of BO-TPE-BO.

Solid phase extraction with Polypyrrole nanofibers for simultaneously determination of three water-soluble vitamins in urine

This paper put forward a prospective pre-cleanup method of packed-fiber solid phase extraction by using Polypyrrole (Ppy) electrospun nanofibers as the sorbent to simultaneously extract three water-soluble vitamins (i.e., folic acid, cyanocobalamin and riboflavin) in human urine. Primary extraction of target analytes was carried out by loading samples onto the column along with diphenylboronic acid 2-aminoethylester (DPBA) reagent, and then the column should be rinsed with DPBA solution for three times before eluting. The DPBA was innovatively applied as complexing reagent to retain as much of three analytes as possible on the column based on the multi interaction between three vitamins and the boronate affinity reagent, thus improving hydrophobicity of targets and adsorption efficiency through loading and rinsing steps. Under optimized conditions, sample concentration factor was five times with small amount of organic solvent consumed and recoveries between 84.9% to 125.4%, and the lowest detection limit (LOD) between 0.020 to 0.041 μg/mL were achieved. Finally, the urine samples from a group of healthy children were processed with the optimized method. It proved that the proposed method is applicable in the determination of urinary B-vitamins in big samples of people.

Fluorescent boron Schiff bases dyes for staining silk fibroin: Green synthesis, structural characterization, DFT, and photophysical properties

Five novel organoboron complexes were synthesized in just 15 min via microware irradiation, by one pot multicomponent reactions between diverse aryl aldehydes with benzoylhydrazide, or 4‐nitrobenzoylhidrazine and diphenyl boronic acid, in a 1:1:1 ratio in benzene. The products were characterized by 1H, 13C, 11B NMR, UV, IR, spectroscopy and high‐resolution mass spectrometry (HRMS). The molecular structure was also determined by single‐crystal X‐ray diffraction for two complexes, which showed the tetra‐coordination of the boron atoms giving rise to distorted tetrahedral molecular geometry with a strong intermolecular C‐H···π interactions. In spite of the low quantum yields exhibited by the series in solution, some complexes stained uniformly the silk fibroins emitting enough fluorescence to allow its characterization by confocal microscopy. Boron as chelate center of the five complexes resulted not to be toxic for B16F10 cells, these compounds are appropriate for their used in medical applications.

Insulin Delivery Platforms: Multiresponsive Supramolecular Theranostic Nanoplatform Based on Pillar[5]arene and Diphenylboronic Acid Derivatives for Integrated Glucose Sensing and Insulin Delivery (Small 38/2018)

Insulin Delivery Platforms: Multiresponsive Supramolecular Theranostic Nanoplatform Based on Pillar[5]arene and Diphenylboronic Acid Derivatives for Integrated Glucose Sensing and Insulin Delivery (Small 38/2018)

A Novel, Automated Dispersive Pipette Extraction Technology Greatly Simplifies Catecholamine Sample Preparation for Downstream LC-MS/MS Analysis.

Catecholamines are integral neurotransmitters in the central and peripheral nervous system. Clinically, catecholamine levels are determined to help diagnose disease and measure corresponding therapeutic effectiveness. However, manual extraction of catecholamines and their metabolites may be labor-intensive and user-variable and require a variety of peripheral laboratory devices, especially at low sample concentrations. Here, we propose a novel solid-phase extraction (SPE) method using patented dispersive pipette extraction (DPX) tip technology. The tips are readily integrated into an automated workflow to extract these compounds from urine, which increases analytical throughput while removing human variability and error. Diphenylboronic acid (DPBA) forms a stable, negatively charged complex with catecholamines in the samples, and when aspirated into the DPX tip, the complexed analytes are retained on a styrene divinyl benzene sorbent. Wash buffers remove interfering compounds, after which the complex is eluted from the tip using an acidic aqueous solution and subsequently measured via liquid chromatography with tandem mass spectrometry (LC-MS/MS). The automated DPX method for catecholamine sample preparation from urine has excellent linearity over more than three orders of magnitude with concentrations ranging from 0.5 to 1000 ng/mL, with replicate analyses resulting in coefficients of variation of less than 8%. This high-throughput workflow is appropriate for use in regulated laboratories.

Multiresponsive Supramolecular Theranostic Nanoplatform Based on Pillar[5]arene and Diphenylboronic Acid Derivatives for Integrated Glucose Sensing and Insulin Delivery.

A closed-loop "smart" insulin delivery system with the capability to mimic pancreatic cells will be highly desirable for diabetes treatment. This study reports a multiple stimuli-responsive insulin delivery platform based on an explicit supramolecular strategy. Self-assembled from a well-designed amphiphilic host-guest complex formed by pillar[5]arene and a diphenylboronic acid derivative and loaded with insulin and glucose oxidase, the obtained insulin-GOx-loaded supramolecular vesicles can selectively recognize glucose, accompanied by the structure disruption and efficient release of the entrapped insulin triggered by the high glucose concentration as well as the in situ generated H2 O2 and acid microenvironment during the GOx-promoted specific oxidation of glucose into gluconic acid. Moreover, such a "smart" supramolecular theranostic nanoplatform is able to function as both a glucose sensor and a controlled insulin delivery actuator. In vivo experiments further demonstrate that this smart supramolecular nanocarrier shows fast response to hyperglycemic circumstances and can effectively regulate the glucose levels in a mouse model of type I diabetes.

Quantification of Metanephrine and Normetanephrine in Urine Using Liquid Chromatography-Tandem Mass Spectrometry.

Measuring urinary metanephrines aides in the diagnosis of pheochromocytomas-catecholamine producing tumors. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) allows for greater sensitivity and simpler sample preparation as compared with other techniques. Here we describe a simple LC-MS/MS method for measuring metanephrines in urine. Each urine sample was treated with diphenylboronic acid to create boronate complexes, and then applied to a Bond-Elut Plexa cartridge. After solid phase extraction, samples were concentrated and analyzed on an Atlantis T3 column with chromatographic run time totaling 8.5 min. MS/MS was set in positive electrospray ionization mode with multiple reaction monitoring for data collection. The assay was linear from 0.2 to 27.4 μmol/L and 0.3 to 14.6 μmol/L for metanephrine and normetanephrine, respectively. Intra-assay and total precision at three concentration levels over 10 days were <5 % for metanephrine and <10 % for normetanephrine.

Mono- and di-phenylboronic acid receptors with fluorescence sensitivity to d-fructose

Three monoboronic acids, namely, [3-(benzoylamindo)phenyl]boronic acid (1), [3-(nicotinamido)phenyl]boronic acid (2), and [3-(isonicotinamido)phenyl]boronic acid (3), as well as four diboronic acids, namely, [3,3′-[N,N′-(paraphthalmido)]biphenyl]diboronic acid (4), [3,3′-[N,N′-(isophthalamido)]biphenyl]diboronic acid (5), [3,3′-[N,N′-(2,6-pyridinedicarboxamido)]biphenyl]diboronic acid (6), and [3,3′-[N,N′-(2,5-pyridinedicarboxamido)]biphenyl]diboronic acid (7), are synthesized using their corresponding acyl chlorides and 3-aminobenzeneboronic acid. All compounds are fully characterized. The crystal structure of compound 3 is determined using single-crystal X-ray diffraction analysis. Fluorescence tests are performed using a general fluorescence assay method called indicator displacement assay, which uses alizarin red S as the optical reagent to monitor the binding of the unmodified boronic acid compound with the carbohydrate. The monoboronic acids show fluorescence quenching for d-fructose in aqueous solution, whereas the diboronic acids show fluorescence enhancement in DMF solutions. The Stern–Volmer plot within the total concentration range of the compounds is linear, indicating significant sphere quenching caused by the interaction between d-fructose and boronic acid receptors.

Degradation of triphenylborane–pyridine antifouling agent in water by copper ions

Triphenylborane–pyridine (TPBP) is an antifouling compound used in Asian countries, including Japan, and its residue has not been detected in aquatic environments to date. There are limited data on its fate for environmental management. The purpose of this study was to evaluate whether TPBP is degraded by metal ions in aquatic environments. TPBP with metal ions in 20 mM sodium acetate buffer at pH 8.0 was placed at 25°C in the dark for 24 h. The concentrations of TPBP and its degradation products, such as diphenylboronic acid, phenylboronic acid (MPB), phenol, benzene, biphenyl, and boron were determined. The presence of copper ions (50 mg/l), but not zinc or manganese ions, resulted in complete degradation of TPBP in 24 h. The TPBP degradation was much faster than the boron production in the initial reaction (0–1 h) with copper salts, depending on the copper salts tested. TPBP was degraded by copper ions (5 mg/l) in 24 h, producing phenol, MPB, biphenyl, and borate. Cu2+ as copper(II) chloride or copper(II) acetate led to complete degradation of TPBP, and ethylenediaminetetraacetic acid disodium salt addition suppressed the TPBP degradation. Cu+ as copper(I) acetate also completely degraded TPBP, and bathocuproine addition suppressed the TPBP degradation. This suggests that copper ions existing in natural environments might degrade TPBP released from antifouling paint into water, and this could be one of the important mechanisms to dissipate TPBP residues in aquatic environments.

A simple liquid chromatography-tandem mass spectrometry method for measuring metanephrine and normetanephrine in urine

Measuring urinary fractionated metanephrines is one of the initial tests in the diagnosis of pheochromocytoma. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) represents the most specific and accurate technology for this purpose. The goal of this work was to develop a simple LC-MS/MS method for measuring metanephrines in urine. Each urine sample was complexed with diphenylboronic acid, and purified on a Bond-Elute Plexa cartridge. The extract was concentrated and analyzed on a short Atlantis T3 column in 8.5 min. Metanephrines and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring. Ion suppression was observed, but was compensated for by the respective internal standard. The analytical measurement range was 0.2-27.4 μmol/L and 0.3-14.6 μmol/L for metanephrine and normetanephrine, respectively. The intra-assay and total coefficient of variation throughout the linear ranges was 2.03%-2.11% and 2.20%-3.80% for metanephrine, and 4.50%-8.09% and 9.00%-10.00% for normetanephrine, respectively. Comparison with a commercial HPLC method using patient samples (n=65) by Passing-Bablok regression showed a slope of 1.000 and 1.014, y-intercept of -0.080 and -0.067, a correlation coefficient of 0.8830 and 0.9022, and a mean difference of 14.0% and -0.43% for metanephrine and normetanephrine, respectively. This simple method for urine metanephrines is suitable for clinical use.

Bioengineering functional copolymers. XII. Interaction of boron-containing and PEO branched derivatives of poly(MA-alt-MVE) with HeLa cells

Novel boron-containing bioengineering copoly- mer and its α-hydoxy-ω-methoxy-poly(ethy- lene oxide (PEO) macrobranched derivatives were synthesized by (1) partially amidolysis of poly(maleic anhydride-alt-methyl vinyl ether) w?th ethanolamine ester of diphenylboronic acid and (2) esterification of synthesized B-con- taining copolymers with PEO. They had a com- bination of hydrophilic/hydrophobic linkages, free carboxylic groups, positive charges and an ionized organoboron linkage as antitumor sites, along with an ability to interact with HeLa cells. The structure, composition and properties (cy- totoxicity and antitumor activity) of synthe- sized copolymers were investigated. In vitro cytotoxicity results, obtained by the fluore scence microscopy measurements indicate that unlike the virgin copolymer, boron-containing and PEO macrobranched derivatives exhibit higher antitumor activity. It was found that organoboron copolymer exhibits the most apo- ptotic and necrotic effects against HeLa cells whereas a minor effect relative to cancer cells was observed on L929 Fibroblast cells.

Synthesis and third-order nonlinear optical studies of a novel four-coordinated organoboron derivative and a bidentate ligand: The effect of the N → B coordinative bond

The third-order nonlinear optical characterization of a new boronate ( 2) derived from 4-dimethylaminocinnamaldehyde was performed by third-harmonic generation (THG) at the infrared wavelength of 1550 nm. Compound 2 was prepared from the reaction of diphenylboronic acid and the bidentate ligand ( 1) and characterization was made through UV, IR, 1H, 11B, and 13C NMR and X-ray diffraction. The THG experiments showed that the N → B coordinative bond in 2 enhanced the second molecular hyperpolarizability of the type γ (3)(−3ω, ω, ω, ω) by a factor of three with respect to the value exhibited by the ligand 1. On the other hand, Z-scan studies at 800 nm (femtosecond (fs) pulses) also showed that such coordinative bond increased the nonlinear absorption (two-photon absorption (TPA)) in 2 with respect to 1. These studies demonstrate that the N → B coordinative bond facilitates the polarization of the electronic π-system, a situation that optimizes the third-order NLO response. Results on the excited state absorptions in these compounds are also presented.

A glucose-selective fluorescence sensor based on boronicacid-diol recognition

A glucose selective diphenylboronic acid fluorescent sensor ( 10a) with a K a of 1472 M −1 has been synthesized and evaluated. This sensor shows a 43- and 49-fold selectivity for glucose over fructose and galactose, respectively. The binding affinity improvement is about 300-fold and the selectivity improvement for glucose over fructose is about 1400-fold compared with the monoboronic acid compound, phenylboronic acid. 1H NMR studies indicate that sensor 10a binds with α- d-glucofuranose in a bidentate manner (1:1 ratio).

A fully automated catecholamines analyzer based on cartridge extraction and HPLC separation

A fully automated analyzer is described for the HPLC analysis of catecholamines. Firstly urinary and plasma catecholamines are reacted with diphenylboronic acid giving a complex without requiring a pH-meter step. This complex is strongly retained on a C 18 cartridge and elution with acetic acid solutions shows recoveries higher than 90 %. The catecholamines are eluted also by the mobile phase employed for the HPLC’ analysis. An intelligent autosampler makes the complex and fills a loop with all the solvents necessary for the sample cleanup. It then inverts the flow and pumps the sample and the solvents throught the cartridge. In the elution step the disposable extraction cartridge is positioned on stream with the HPLC analytical column by an automatic sampler. The separation is performed by ion-pair reversed-phase high-performance liquid chromatography, with sodium dodecyl sulphate as pairing ion, a short analytical column and electrochemical detection. The HPLC analysis time is 3 min and the total sample turnover time is 8 min. The recoveries and the precision of the analyzer are given together with correlation with manual HPLC.

ChemInform Abstract: Reactions of 1,3,5,2‐Dioxaphosphoniaborinanes with Aldehydes and Nitriles.

AbstractPhenylphosphine (I), the aldehydes (II), and diphenylboronic acid isobutylester (III) are combined to give the title compounds (IV).

ChemInform Abstract: Synthesis of Ammonium 1,3,5,2‐Dioxaphosphaboratinanes.

AbstractThe title compounds (IV) may be obtained either from bis‐α‐hydroxyalkylphenylphosphines (I) and diphenylboronic acid isobutylester (II) in excess amine (III) or from diphenylphosphine (V) and the aldehydes (VI), the ester (II), and the amine (IIIa).

Borchelate und Bormetallchelate, VI [1] Zur Bildung von Borchelaten aromatischer Azoverbindungen / Boron Chelates and Boron Metal Chelates, VI [1]The Formation of Boron Chelates of Aromatic Azo Compounds

Bidentate chelate reagents incorporating a suitable group (e.g. OH, NH2) in ortho position to the azo-group react with diphenylboronic acid anhydride or boron trihalides (BF3, BCl3) resulting in the BR2-six membered ring-chelates of types 1 and 2. The products of the reaction of tridentate chelate reagents with phenylboronic acid or boron trifluoride at elevated temperature are BR-chelates with two six membered rings (types 3 and 4). The conditions of the formation of the bicyclic chelates 5 and 6 depend on the position of the substituents of the chelate reagents. The incorporation of only one BR2 group is possible if the order of the substituents in 2,2′-dihydroxyazobenzenes is not symmetrical (chelates of the type 7). Structural isomers of boron chelates of the types 5, 6 or 7 with Nα/Nβ isomerism have not yet been observed. The identification of the structures of the above-mentioned complexes was achieved by means of 1H, 11B and 19F NMR and IR spectroscopy. For mass spectrometric analysis see ref. [2].