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Because of the biological importance of CO, the development of effective probes for the detection of CO in living systems is of great significance. In particular, near-infrared (NIR) fluorescence probes with good water solubility and large Stokes shift are indispensable tools for CO detection in vivo. However, such tools are extremely scarce. Herein, a modified rhodol dye was used to develop a novel NIR fluorescent probe (Rh-NIR-CO) for selective and sensitive detection of CO using the Pd0-mediated Tsuji-Trost reaction. This probe shows good water solubility and rapid CO detecting ability in aqueous buffer at pH 7.4, accompanied by distinct colorimetric and turn-on NIR emission changes at 676 nm with a large Stokes shift (135 nm) and low detection limit (37 nM). Moreover, NIR fluorescence imaging of CO in living cells, zebrafish, and living mice was successfully applied with this probe. These excellent results highlighted Rh-NIR-CO as a promising new tool for in vitro and in vivo detection of CO.

The hydrolytic decomposition of four peptides containing S-aroylthiooximes (SATOs) with variable N-arylidene substituents was investigated in 10 aqueous buffer solutions at pH values ranging from 6.0 to 10.9. UV-Vis spectroscopy was employed to study the reaction kinetics, which revealed V-shaped pH-rate profiles for all peptides with a minimum near pH 8, suggesting a change from an acid-catalyzed to a base-activated reaction. Hammett plots showed positive ρ values above pH 8 and negative ρ values below pH 8, providing further evidence for a mechanism change. Based on these data, along with mass spectrometry evidence, we propose a specific acid catalysis under mildly acidic and neutral conditions and multiple base-promoted decomposition reactions under mildly basic conditions.

The sensitive imaging of amyloid-β (Aβ) peptides is important for the timely detection of neurodegenerative diseases, such as Alzheimer's disease (AD). Although clinically the diagnosis of AD relies on the use of radiolabeled imaging reagents, herein we report the simple construction of a "flat ensemble" formed between a quinoline-malononitrile AIEgen (EDS) and thin-layer molybdenum disulfide (2D MoS2 ) for the sensitive detection of Aβ by means of fluorescence-based techniques. Self-assembly between EDS and 2D MoS2 in aqueous buffer solution produces the flat ensemble, and the subsequent interaction of the material ensemble with oligomeric and aggregated Aβ peptides leads to up to 19-fold enhanced fluorescence of EDS. The ensemble is also applicable for staining Aβ aggregates in vivo.

The inhibitory efficacy of two substituted coumarin derivatives on the activity of neurodegenerative enzyme acetylcholinesterase (AChE) was assessed in aqueous buffer as well as in the presence of human serum albumin (HSA) and compared against standard cholinergic AD drug, Donepezil (DON). The experimental data revealed the inhibition to be of non-competitive type with both the systems showing substantial inhibitory activity on AChE. In fact, one of the tested compounds Chromenyl Coumarate (CC) was found to be better inhibitor (IC50 = 48.49 ± 5.6 nM) than the reference drug DON (IC50 = 74.13 ± 8.3 nM), unequivocally amplifying its importance. The structure of the compound was found to play a vital role in the inhibitory efficiency, validating previous Structure Activity Relationship (SAR) reviews for coumarin. The mechanism of inhibition remained impervious when the experimental medium was switched from aqueous buffer to HSA, albeit noticeable change in the inhibition potency of the compound 3, 3′- Methylene-bis (4-hydroxy coumarin) (MHC) (38%) and CC (35%). Both the coumarin derivatives were observed to bind to the peripheral anionic site (PAS) of AChE and also found to displace the fluorescence marker thioflavinT (ThT) from AChE binding pocket. All experimental observations were seconded by molecular docking and MD simulation results. The inferences drawn in this study form a foundation for further investigation on these compounds; magnifying the probability of their usage as AD drugs and re-emphasizes the significance of drug delivery media while considering the inhibition potencies of targeted drugs.

The inhibitive action of some azoles (1,2,4-triazole, 1,2,3-benzotriazole, 5-chlorobenzotriazole, and IFKhAN-92 corrosion inhibitor) on the corrosion of magnesium was investigated in aqueous buffer solutions and humid atmosphere. Increasing the hydrophobicity and decreasing the pKa of NH-acids enhance the protection of Mg by triazoles, that is why 5-chlorobenzotriazole and IFKhAN-92 – a mixture of substituted triazoles – are more efficient inhibitors. Small additions of dioctylphosphate increase the protection of Mg in aqueous solution by IFKhAN-92 inhibitor, and addition of trialkoxysilane to the mixed inhibitor allows one to enhance the protection of Mg in a humid atmosphere.

Self-assembled states of proteins render efficient promiscuous nucleophilic biocatalysis in MBH reaction in a green process. The His and Arg based catalophores in proteins operate in aqueous buffer at neutral pH and ambient temperature. Steady-state fluorimetric approaches reveal that lower order aggregates play a seminal role in the biocatalytic process.

A naphthalimide-based fluorescence light-up probe, FCP-Pd, has been designed and synthesized for selective detection and quantitation of creatinine in PBS buffer of pH 7.2 at 37 °C with a 'turn-on' response over a variety of interfering metal ions and/or anions and several biologically significant species. This probe is highly effective in estimating creatinine in human blood serum, which confirms the reliability and accuracy of this new system to be applied in clinical and toxicological analysis.

The interactions of L-phenylalanine and L-tryptophan with nicotinic acid and uracyl in an aqueous buffer solution at pH 7.35 were studied by IR spectroscopy. The contributions of various functional groups to the complexation of aromatic amino acids with heterocyclic ligands were determined from the IR spectra of the starting substances and their mixtures.

A novel Cu2+-specific colorimetric hydrazone sensor 1 was designed and developed. The color of 1 changes from colorless to pink on addition of 10.0 μM Cu2+ in aqueous buffer solution, which can be detected by the naked eye. The analytical detection limit for Cu2+ by the naked eye is as low as 2.0 μM. The stoichiometry for 1 and Cu2+ in complex is 2:1 in aqueous solution.

The impact of temperature, emulsifier, and protein type on the reactivity of malondialdehyde in oil-in-water emulsions was elucidated. Malondialdehyde recoveries in aqueous buffer, protein solutions, saturated oil, and fully hydrogenated coconut oil-in-water emulsions stabilized by whey proteins or Tween 20 at 4 or 40 °C were compared. At both temperatures, the reactivity of malondialdehyde in aqueous buffer was the same. In protein solutions, malondialdehyde concentrations were reduced further and its decrease was protein-dependent. Similar trends were found for emulsions. Surprisingly, malondialdehyde was very reactive in saturated oil because only 15% was recovered at 40 °C. However, the degradation in oil proved to be strongly temperature-dependent; at 4 °C, losses amounted to only 8%. This study revealed that malondialdehyde is a very reactive molecule, both in the presence and absence of proteins. Its use as a general oxidation marker should therefore be considered with care.

A metal-free method for fast and clean anilide formation from perfluoroaryl azide and thioacid is presented. The reaction proved highly efficient, displaying fast kinetics, high yield, and good chemoselectivity. The transformation was compatible with various solvents and tolerant to a wide variety of functional groups, and it showed high performance in polar protic/aprotic media, including aqueous buffer systems.

The effects of AOT reverse micelle system on the physicochemical properties of soy proteins were studied in this work. The aggregate size of soy proteins using AOT reverse micelle extraction was much larger than that using aqueous buffer extraction. After AOT reverse micelle treatment, the color differences of protein powder are significative, sulfhydryl and disulfide contents of soy proteins decreased, but surface hydrophobicity greatly increased. Compared to soy proteins from aqueous buffer extraction, the enthalpy, onset temperature and peak temperature of the proteins from AOT reverse micelle extraction increased. The textural analyses of the gels of the soy proteins presented higher hardness, adhesiveness, gumminess, chewiness and lower cohesiveness, springiness.

The development of functionalized materials is needed to enable diverse applications. Protein-based materials are typically biocompatible and biodegradable and can exhibit a wide variety of useful mechanical properties. Most importantly, gene fusion enables facile incorporation of active proteins into the materials. However, many protocols rely on denaturing conditions to stimulate materials formation. These conditions would be expected to inactivate any appended functional proteins. This chapter describes methods to create protein fibers and films in a mild aqueous buffer near neutral pH. This facile, inexpensive single-pot approach to materials assembly does not require any special equipment. Also included in this chapter are methods to fuse fibers to form fiber bundles, and to use fibers for cell culture. Although these methods were developed to generate materials from the Drosophila Hox transcription factor Ultrabithorax, they may also work for other self-assembling proteins, many of which have sequence features in common with Ubx.

A new simple receptor 1 based on quinoline was synthesized as a water-soluble fluorescent ‘turn-on’ chemosensor for zinc ions. In 100% aqueous buffer solution, sensor 1 displayed a selective fluorescence enhancement (317-fold) at 536 nm with Zn2+. The detection limit (4.48 μM) of 1 for Zn2+ was far below the WHO guideline (76 μM) in drinking water. Importantly, sensor 1 could be used to detect and quantify Zn2+ in water samples. Moreover, the sensing ability of 1 for Zn2+ was supported by theoretical calculations. Thus, this sensor 1 has the ability to be a practical system for monitoring Zn2+ concentrations in aqueous samples.

A new coumarin-rhodamine conjugate is used as a specific probe for Pd(2+) ions and this could even delineate Pd(II) from Pd(0) or Pd(IV) in aqueous buffer medium (pH ∼ 7). Laser confocal microscopic studies reveal that efficient cellular internalization of this reagent helps in imaging the cellular uptake of Pd(2+) as low as 0.1 ppm in Hct 116 cells. This reagent could even be used for estimation of Pd(2+) in human urine samples.

A Cu(2+)-specific colorimetric reversible fluorescent receptor was designed and synthesized which showed a naked eye observable colour change from colourless to pink on addition of an aqueous buffer (pH 7.4) solution of 30 ppb Cu(2+). Short response time (≤5 s) and low detection limit (nearly 3 ppb) make suitable as a reliable "dip-in" open eye sensor for Cu(2+). Bio-imaging application in live brine shrimp Artemia enabled to detect Cu(2+) at as low as 10 ppb exposure.

We present the concept, synthesis, and kinetic characterization of PYRROC as the first functionalized cycloalkyne which cannot form isomers in the reaction with azides. In aqueous buffer, PYRROC displays unprecedented rate accelerations in SPAAC of three to four orders of magnitude, leading to rate constants exceeding 400 M(-1) s(-1).

Thiamin analogs were used to synthesize mono gold(i)-carbene derivatives in a single step under aqueous conditions. The resulting thiazolium gold(i)-carbenes catalyze 5-endo-dig carbocyclization of an acetylenic dicarbonyl compound in organic solvents and hydroalkoxylation of an allene in aqueous buffer.

The optical and fluorescent properties of the modern preparations (Fotoditazin, Radachlorin, Photolon, Dimegin) have been studied and compared. These agents are used for Photodiagnosis and Photodinamic therapy of tumors. The spectroscopic studies were carried out on the preparations dissolved in different water-based media and their values of fluorescence quantum yields have been calculated too. The various media were prepared in order to model the porhyrins' behavior in the blood with different degrees of approximation.

The electrochemical sensing of new psychoactive substance(s) (NPSs), synthetic cathinone derivatives also termed "legal highs", are explored with the use of metallic modified screen-printed electrochemical sensors (SPES). It is found that no significant electrochemical enhancement is evident with the use of either in situ bismuth or mercury film modified SPES compared to the bare underlying electrode substrate. In fact, the direct electrochemical reduction of the cathinone derivatives mephedrone (4-methylmethcathinone; 4-MMC) and 4'-methyl-N-ethylcathinone (4-methylethcathinone; 4-MEC) is found to be possible for the first time, without heavy metal catalysis, giving rise to useful voltammetric electroanalytical signatures in model aqueous buffer solutions. This novel electroanalytical methodology is validated toward the determination of cathinone derivatives (4-MMC and 4-MEC) in three seized street samples that are independently analyzed with high-performance liquid chromatography (HPLC) wherein excellent agreement between the two analytical protocols is found. Such an approach provides a validated laboratory tool for the quantification of synthetic cathinone derivatives and holds potential for the basis of a portable analytical sensor for the determination of synthetic cathinone derivatives in seized street samples.

Cosmetic hair treatments have been referred to as 'the pitfall' of hair analysis. However, most cosmetic treatments, when applied to the hair as instructed by the product vendors, do not interfere with analysis, provided such treatments can be identified by the laboratory and the samples analyzed and reported appropriately for the condition of the hair. This paper provides methods for identifying damaged or porous hair samples using digestion rates of hair in dithiothreitol with and without proteinase K, as well as a protein measurement method applied to dithiothreitol-digested samples. Extremely damaged samples may be unsuitable for analysis. Aggressive and extended aqueous washing of hair samples is a proven method for removing or identifying externally derived drug contamination of hair. In addition to this wash procedure, we have developed an alternative wash procedure using 90% ethanol for washing damaged or porous hair. The procedure, like the aqueous wash procedure, requires analysis of the last of five washes to evaluate the effectiveness of the washing procedure. This evaluation, termed the Wash Criterion, is derived from studies of the kinetics of washing of hair samples that have been experimentally contaminated and of hair from drug users. To study decontamination methods, in vitro contaminated drug-negative hair samples were washed by both the aqueous buffer method and a 90% ethanol method. Analysis of cocaine and methamphetamine was by liquid chromatography-tandem mass spectrometry (LC/MS/MS). Porous hair samples from drug users, when washed in 90% ethanol, pass the wash criterion although they may fail the aqueous wash criterion. Those samples that fail both the ethanolic and aqueous wash criterion are not reported as positive for ingestion. Similar ratios of the metabolite amphetamine relative to methamphetamine in the last wash and the hair is an additional criterion for assessing contamination vs. ingestion of methamphetamine.

Push–pull-type purine nucleoside-based fluorescent sensor L1 bearing a chelating N,N-bis(2-pyridylmethyl)amine group at the C6 position was designed and synthesized. Sensor L1 showed clear and selective detection of Pd2+ in aqueous buffer, and it is the first “on–off”-type purine nucleoside-based fluorescent sensor for Pd2+.

The wide use of palladium species may cause palladium pollution in medicine, food and water, which raises risks on environment and health due to the latent hazard of palladium species. In this work, two BODIPY-based fluorescent probes ( BDP-COOen and BDP-COOyn ) for the detection of palladium have been developed. Both probes displayed strong AIE fluorescence and exhibited selective response to Pd 0 in aqueous buffer. Notably, BDP-COOen showed a favorable two-channel responsive manner as well as preferred reaction kinetics ( BDP-COOen was successfully applied for two channel fluorescence imaging of intracellular Pd 0 .

The peak shapes of 4 anthracyclines have been investigated using isoeluotropic mixtures of acetonitrile, methanol and tetrahydrofuran (THF) in combination with formate buffer at pH 2.9 on a silica column. With aqueous or aqueous-rich mobile phases, no significant differences in overloading behavior have been found with various organic modifiers. With organic-rich mobile phases, peak shape and its dependence on sample size are notably different when organic modifier concentration is changed. Pure aqueous buffer produces the overloaded peak profiles of the solutes associated with a typical Langmuir isotherm, while distinct anti-Langmuirian peaks have been achieved with organic-rich eluents. The general similarity of the loading behavior for the solutes with acetonitrile, THF or isopropanol has been reflected either in aqueous-rich or organic-rich eluents, suggesting that the nature of organic modifier dont dominate the peak shape but water content in the mobile phases.

Ligand design that allows a Hg(ii)–η2-arene π-interaction as well as a TBET-based luminescence response to distinguish between the cellular uptake of Hg2+ and H+ in live Hct116 colon cancer cells.

Simple chromogenic sensor for the selective detection of Cu2+ was described. With the addition of Cu2+, a bathochromic shift about 82 nm was observed in the UV–VIS spectra, with the color change from colorless to bright yellow. This suggested that the coordination between receptor and Cu2+ was formed, and the strong push–pull system occurred. The followed IR spectra indicated that Cu2+ coordinated to the two phenolic oxygen atoms and one of two azomethines in the receptor.

Generous donors: The dithioperoxyanhydrides (CH3 COS)2 , (PhCOS)2 , CH3 COSSCO2 Me and PhCOSSCO2 Me act as thiol-activated hydrogen sulfide donors in aqueous buffer solution. The most efficient donor (CH3 COS)2 can induce a biological response in cells, and advantageously replace hydrogen sulfide in ex vivo vascular studies.

E-mail: hwang817@naver.com (I. H. Hwang); chealkim@seoultech.ac.kr (C. Kim)Received March 20, 2013, Accepted April 2, 2013A simple colorimetric and fluorescent anion sensor 1 based on salicylimine showed a high selectivity andsensitivity for detection of cyanide in aqueous solution. The receptor 1 showed high selectivity toward CN

A bromoacetyl functionalized fluorescein chemodosimeter (1) was utilized as a fluorescent probe for cysteine. The probe showed a selective and sensitive response to cysteine over homocysteine and glutathione in aqueous buffer through a rapid cyclization reaction. When cysteine was added, a fast fluorescence turn-on change of 1 was observed, thus allowing cysteine to be discriminated from other biothiols and micromolar concentrations of cysteine to be detected by the naked eye.

We introduce two water-soluble ruthenium complexes, RuPD and RuPP, and show their potential as probes for luminescent recognition of diacetyl. The recognition involves the reaction of diacetyl with a diamine moiety to convert the almost nonluminescent complex into a stronger emitting species with an up to 31-fold increase of luminescence. The incubation time could be reduced by a factor of 2.5 with respect to our former rhodamine B-based probe for diacetyl. Moreover, RuPD is the first probe that permits determination of diacetyl in aqueous buffer at neutral pH and (even more sensitive) at acidic pH in micromolar concentrations. RuPD reacts more selectively with diacetyl than with other carbonyls and shows longwave emission at 625 nm. This provides an assay for diacetyl that is hardly prone to co-excited background luminescence in biological environments as shown by its application in spiked samples of cell nutrition medium.

A straightforward, sensitive, and selective fluorescent turn-on probe based on the AuNPs/ 1 -PR 3 + electrostatic adsorbate was applied to the detection of intracellular thiols such as cysteine, homocysteine, and glutathione in both aqueous buffer solutions (pH 7.4) and living cells.

The activity of a gold nanoparticle-based catalyst can be reversibly up- and down-regulated by light. Light is used to switch a small molecule between cis- and trans-isomers, which inhibits the catalytic activity of the nanoparticles to different extent. The system is functional in aqueous buffer, which paves the way for integrating the system in biological networks.

This chapter focuses on fluorine-based probes and pays particular attention to their use for cell tracking with MRI. Most of these probes incorporate perfluorocarbon molecules that are formulated as colloidal suspensions or emulsions in aqueous buffer. A discussion on the design of fluorine probes and emulsions is followed by a description of the acquisition of 19F MRI phantoms.

5-Oxatetracyclines were synthesized from d-arabinose using sequential Michael–Claisen cyclization reactions via a 5-oxa-AB enone substrate. The 5-oxatetracyclines were found to have poor stability in aqueous buffer (pH 7.4, 37 °C) and showed little to no inhibition of bacterial growth (S. aureus, E. coli).

We disclose the highly diastereoselective combination of monoamine oxidase-catalyzed oxidation of meso-pyrrolidines and aza-Friedel–Crafts reactions in aqueous buffer to give valuable enantioenriched 2-substituted pyrrolidines in a formal double CH activation process. A range of secondary as well as tertiary amines were shown to be suitable substrates for the biocatalytic oxidation and subsequent addition of a variety of C-nucleophiles.

Five derivatives of 2, 3, 3-trimethyl-3H-indolium containing different electron donor groups (H1 - H5) were synthesized for the determination of proteins. H3, a sensitive red-emitting fluorescent probe, was found for the discrimination of hydrophobic proteins from hydrophilic. The OFF - ON fluorescence switch of H3 was caused by the formation of twisted intramolecular charge-transfer (TICT) state when it combined with hydrophobic proteins in aqueous buffer. There was a good linear relationship between the emission intensity of H3 and the casein concentration (r = 0.9989). Based on this, a novel casein quantitative assay method was developed, and the method was applied to determinate casein in milk powder samples. Successfully, the results were in good agreement with Biuret method. In addition, a simple and sensitive method was established to differentiate and quantify three casein components (α-, β-, and κ-casein) due to their much different binding constants to H3 probe.

UV-Vis spectroscopy, hplc-mass spectrometry and deuterium-labeling studies demonstrate that 4-alkyl-ortho-quinones cleanly rearrange to the isomeric 2-hydroxy-para-quinomethanes over a period of 10-20 minutes in aqueous buffer. These ortho-quinones are much more stable in organic solvents (CD3OH, CDCl3). Studies of the rate of rearrangement and of the introduction of pre-formed para-quinomethane to enzyme solution demonstrate that the quinomethanes, formed as secondary products, do not contribute to the inactivation of tyrosinase. ©ARKAT USA, Inc.

The viability of using a pad printing technique for the production of disposable electrode systems has been assessed. The morphology and structural characteristics of the carbon ink layers has been characterised and the electrochemical behaviour of the resulting layers investigated using a number of model systems. Voltammetric and potentiometric methodologies (in aqueous buffer and acetonitrile) were conducted using ferrocence carboxylic acid and naphthoquinone-thiol systems. The ability to create modified electrode assemblies through the incorporation of indicators directly within the ink prior to printing has been shown to provide a facile means through which the selectivity of the electrodes can be enhanced and provides a quick means of prototyping reagentless sensors. © 2004 Elsevier B.V. All rights reserved.

Common drugs intended for action in plasma (antibacterials, antiallergics, diuretics...) often display both acidic and basic behavior, and some of these amphoteric compounds can appear as zwitterions. In such cases, accurate profiling of lipophilicity vs. pH, which plays a fundamental role in drug pharmacokinetics, might be complex. In the present work two common lipophilicity determination methods based on the drug distribution between 1-octanol and aqueous buffer i.e. phase equilibration (shake-flask) and two-phase titration (potentiometry), were compared with a high-throughput lipophilicity index, the Chromatographic Hydrophobicity Index (CHI). The results were also compared with log Do/w pH-profiles calculated by different algorithms from ACD/Labs. Accurate and similar results were obtained for both octanol-water approaches but, due to the lower determination times and the absence of different ion-pairing buffers, potentiometry was shown to be the most convenient method. CHI vs. pH profiles provide rapid and efficient information, which is very convenient for lipophilicity screening purposes, but may differ slightly from shake-flask and potentiometric results.

In the past 30 years, the atomic force microscope (AFM) has become a true enabling platform in the life sciences opening entire novel avenues for structural and dynamic studies of biological systems. It enables visualization, probing and manipulation across the length scales, from single molecules to living cells in buffer solution under physiological conditions without the need for labeling or staining of the specimen. In particular, for structural studies of nucleic acids and assemblies thereof, the AFM has matured into a routinely used tool providing nanometer spatial resolution. This includes ssRNA, dsRNA and nucleoprotein complexes thereof, as well as RNA aggregates and 2D RNA assemblies. By AFM unique information can be obtained on RNA based assemblies which are becoming increasingly important as novel unique building blocks in the emerging field of RNA nanotechnology. In addition, the AFM is of fundamental relevance to study biological relevant RNA interactions and dynamics. In this short review first the basic functioning principles of commonly used AFM modes including AFM based force spectroscopy will be briefly described. Next a brief overview will be given on structural studies that have been done related to AFM topographic imaging of RNA, RNA assemblies and aggregates. Finally, an overview on AFM beyond imaging will be provided. This includes force spectroscopy of RNA under physiological conditions in aqueous buffer to probe RNA interaction with proteins and ligands as well as other AFM tip based RNA probing. The main intention of this short review to give the reader a flavor of what AFM contributes to RNA research and engineering.

MEEKC is a mode of CE, which utilizes microemulsion (ME) as the BGE to achieve separation of a diverse range of analytes. MEs are composed of nanometer-sized oil droplets suspended in aqueous buffer which are stabilized by the presence of a surfactant and co-surfactant. These MEs are commonly referred to as oil-in-water MEs and their application in MEEKC has been extensively examined. This review details advances in the theory, methodology, and application of MEEKC during the period 2010-2012. Areas covered include online sample concentration, advances in chiral separations, use of coated capillaries, chemometric approaches, and the use of novel additives to the ME system. This review also provides the reader with an introduction to MEEKC and a presentation of recent applications.

Copper leads to a breakup: simple Cu(II) salts are shown to be highly reactive as water oxidation electrocatalysts in neutral to weakly basic aqueous buffer solutions of CO(2)/HCO(3)(-)/CO(3)(2-) or HPO(4)(2-)/PO(4)(3-). Coordination to the buffer anions under these conditions prevents the precipitation of Cu(OH)(2), CuCO(3), or Cu(3)(PO(4))(2) and appears to stabilize higher oxidation states of copper.

We report a novel latent colorimetric probe ( 1 ) for cyanide, which possesses a masked phenol in the para position of an azo dye group. Upon the addition of cyanides, probe 1 undergoes a ring opening reaction through the Michael addition of cyanide ion and a subsequent [1,3]-sigmatropic rearrangement reaction to give rise to a stable free phenol, whose signal is transduced to the azo dye unit producing a dramatic color change.

Catalytic oxidation of softwood cellulose using NaClO and either 2,2,6,6-tetramethylpiperidine-1-oxyl (4-H-TEMPO) or 4-acetamido-TEMPO (4-AcNH-TEMPO) was applied with NaClO(2) used as a primary oxidant in an aqueous buffer at pH 4.8 or 6.8. When the 4-AcNH-TEMPO-mediated oxidation was applied to softwood cellulose in water at pH 4.8 and 40 °C, the carboxylate content rose to ∼1.3 mmol/g after reaction for 48 h and the DP(v) value was more than 1100. This 4-AcNH-TEMPO-oxidized softwood cellulose was mostly converted to individual nanofibrils by mechanical disintegration in water, with uniform widths of 3-4 nm and lengths greater than 1 μm.

A definition of the scope of aromatic substrates that participate with catharanthine in an Fe(III)-mediated coupling reaction, an examination of the key structural features of catharanthine required for participation in the reaction, and the development of a generalized indole functionalization reaction that bears little structural relationship to catharanthine itself are detailed. In addition to providing insights into the mechanism of the Fe(III)-mediated coupling reaction of catharanthine with vindoline suggesting the reaction conducted in acidic aqueous buffer may be radical mediated, the studies provide new opportunities for the preparation of previously inaccessible vinblastine analogs and define powerful new methodology for the synthesis of indole-containing natural and unnatural products.

A naphthocoumarin-based chemosensor capable of sensing cyanide and cadmium ions was designed through a reversible reaction with the two toxins. It exhibited rapid reversible fluorescence responses to cyanide anions through Michael addition and to cadmium cations through metal-induced elimination with reversible cycling in aqueous buffer.

Commercially available hops (Humulus lupulus L.) bitter acid extracts contain a mixture of three major congeners (co-, n-, and ad-) in addition to cis/trans diastereomers for each congener. Individual isomerized α-acids were obtained by the consecutive application of two separate countercurrent chromatography methods. First, individual isomerized α-acid congeners as a mixture of cis/trans diastereomers were obtained using a solvent system consisting of hexane and aqueous buffer. The second purification, capable of separating cis/trans diastereomers, was accomplished using a quaternary solvent system; an alternative procedure using β-cyclodextrin followed by countercurrent chromatography was also investigated. The NaBH(4) reduction of the purified isomerized α-acid compounds followed by countercurrent chromatography purification resulted in individual ρ iso α-acids (>95%). Similarly, catalytic hydrogenation of the purified isomerized α-acid compounds followed by countercurrent chromatography purification produced individual tetrahydro isomerized α-acids (>95%). Reported herein is a widely applicable approach that focuses on three critical variables--solvent system composition, pH, and buffer-to-sample ratio--that enable the efficient purification of individual bitter acids (≥95%) from commercially available hops extracts.