Publications by authors named "Timothy E Glass"

27 Publications

  • Page 1 of 1

A novel water-soluble fluorescence probe based on ICT lighten for detecting hydrogen sulfide and its application in bioimaging.

Spectrochim Acta A Mol Biomol Spectrosc 2019 May 19;214:355-359. Epub 2019 Feb 19.

Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China. Electronic address:

Endogenous HS, considered to be involved in many physiological processes, has attracted more attention in fluorescence detection and bioimaging. Therefore, it is necessary to design probes with good biocompatibility and high bioavailability. In this study, a novel fluorescent probe, QN-1, based on azide group and quinoline derivatives was developed for detecting HS. QN-1 can detect HS specifically in aqueous phase, which indicated QN-1 has excellent water solubility. Besides, QN-1 shows excellent properties of higher selectivity and 11-fold fluorescence enhancement at 533 nm. Therefore, QN-1 with excellent properties can be used for cell imaging.
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http://dx.doi.org/10.1016/j.saa.2019.02.073DOI Listing
May 2019

A High-Affinity Fluorescent Sensor for Catecholamine: Application to Monitoring Norepinephrine Exocytosis.

Angew Chem Int Ed Engl 2019 06 23;58(23):7611-7614. Epub 2019 Apr 23.

Department of Chemistry, University of Missouri, Columbia, Missouri, 65211, USA.

A fluorescent sensor for catecholamines, NS510, is presented. The sensor is based on a quinolone fluorophore incorporating a boronic acid recognition element that gives it high affinity for catecholamines and a turn-on response to norepinephrine. The sensor results in punctate staining of norepinephrine-enriched chromaffin cells visualized using confocal microscopy indicating that it stains the norepinephrine in secretory vesicles. Amperometry in conjunction with total internal reflection fluorescence (TIRF) microscopy demonstrates that the sensor can be used to observe destaining of individual chromaffin granules upon exocytosis. NS510 is the highest affinity fluorescent norepinephrine sensor currently available and can be used for measuring catecholamines in live-cell assays.
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http://dx.doi.org/10.1002/anie.201810919DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6534456PMC
June 2019

Near-Infrared Fluorescent Rosol Dye Tailored toward Lymphatic Mapping Applications.

Anal Chem 2019 02 6;91(4):3110-3117. Epub 2019 Feb 6.

Molecular Imaging Program at Stanford (MIPS), Department of Radiology , Stanford University School of Medicine , Stanford , California 94305 , United States.

An optical molecular imaging contrast agent that is tailored toward lymphatic mapping techniques implementing near-infrared (NIR) fluorescence image-guided navigation in the planning and surgical treatment of cancers would significantly aid in enabling the real-time visualization of the potential metastatic tumor-draining lymph node(s) for their needed surgical biopsy and/or removal, thereby ensuring unmissed disease to prevent recurrence and improve patient survival rates. Here, the development of the first NIR fluorescent rosol dye (THQ-Rosol) tailored to overcome the limitations arising from the suboptimal properties of the generic molecular fluorescent dyes commonly used for such applications is described. In developing THQ-Rosol, we prepared a progressive series of torsionally restrictive N-substituted non-NIR fluorescent rosol dyes based on density functional theory (DFT) calculations, wherein we discerned high correlations amongst their calculated energetics, modeled N-C3' torsion angles, and evaluated properties. We leveraged these strong relationships to rationally design THQ-Rosol, wherein DFT calculations inspired an innovative approach and synthetic strategy to afford an uncharged xanthene core-based scaffold/molecular platform with an aptly elevated p K value alongside NIR fluorescence emission (ca.700-900 nm). THQ-Rosol exhibited 710 nm NIR fluorescence emission, a 160 nm Stokes shift, robust photostability, and an aptly elevated p K value (5.85) for affording pH-insensitivity and optimal contrast upon designed use. We demonstrated the efficacy of THQ-Rosol for lymphatic mapping with in vitro and in vivo studies, wherein it revealed timely tumor drainage and afforded definitive lymph node visualization upon its administration and accumulation. THQ-Rosol serves as a proof-of-concept for the effective tailoring of an uncharged xanthene core-based scaffold/molecular platform toward a specific imaging application using rational design.
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http://dx.doi.org/10.1021/acs.analchem.8b05709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516061PMC
February 2019

A novel near-infrared ratiometric fluorescent probe for cyanide and its bioimaging applications.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Feb 22;209:95-99. Epub 2018 Oct 22.

Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China. Electronic address:

A new near-infrared ratiometric type fluorescent probe was prepared. 3-formyl BODIPY derivatives without substituent group in the 2, 6-position was obtained through DDQ oxidation reaction. Furthermore, it reacted with indole salt to produce probe. This probe bears indolium group as the recognition site and the 3-formyl-BODIPY as fluorophore. The specific detection of cyanide was conducted the nucleophilic attack of cyanide toward the indolium group of the probe, breaking the intramolecular charge transfer (ICT) effect and generating a ratio change in the fluorescence signal. The probe has high selectivity and sensitivity for cyanide. Moreover, cell experiments indicated this probe was benign to HepG-2 cells, and has the potential application in imaging CN in living HepG-2 cells.
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http://dx.doi.org/10.1016/j.saa.2018.10.037DOI Listing
February 2019

A Multi-Component Sensor System for Detection of Amphiphilic Compounds.

Angew Chem Int Ed Engl 2018 09 30;57(39):12741-12744. Epub 2018 Aug 30.

Department of Chemistry, University of Missouri, 601 S. College Ave., Columbia, MO, 65211, USA.

Many biologically important compounds are amphiphilic in character. Glycolipids, for example, represent a biologically important class of amphiphiles. Receptors and sensors for such compounds must also be amphiphilic making them a challenge to prepare. Here, a cucurbit[8]uril (CB[8])-based sensor system has been prepared and tested for detection of amphiphilic compounds. This multi-component system consists: a CB[8], which acts as a hydrophobic lipid receptor, a hydrophilic pyridinium-based carbohydrate receptor, and a fluorescent indicator. The system self-assembles in aqueous solution. The pyridinium quenches the fluorescence of the indicator giving a strong turn-on response when it is displaced by the analyte. The sensor system was characterized by NMR, X-ray crystallography, and fluorescence titrations.
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http://dx.doi.org/10.1002/anie.201807221DOI Listing
September 2018

A Two-Input Fluorescent Logic Gate for Glutamate and Zinc.

ACS Chem Neurosci 2017 06 6;8(6):1159-1162. Epub 2017 Mar 6.

Department of Chemistry, University of Missouri , 601 South College Avenue, Columbia, Missouri 65211, United States.

The direct visualization of neurotransmitters is a continuing problem in neuroscience; however, functional fluorescent sensors for organic analytes are still rare. Herein, we describe a fluorescent sensor for glutamate and zinc ions. The sensor acts as a fluorescent logic gate, giving a turn-off response to glutamate or zinc ion alone. The combination of analytes produces a large increase in fluorescence. This type of sensor will aid in the study of neurotransmission, in this case, for neurons that copackage high concentrations of zinc and glutamate.
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http://dx.doi.org/10.1021/acschemneuro.6b00420DOI Listing
June 2017

A novel method for the synthesis of 1,2-benzisoxazoline-3-one and its application to hypochlorite recognition.

J Mater Chem B 2016 Aug 14;4(30):5101-5104. Epub 2016 Jul 14.

Institute of Molecular Science, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Shanxi University, Taiyuan 030-006, P. R. China.

The reaction of salicylhydroxamic acid with hypochlorite produces 1,2-benzisoxazoline-3-one, a heterocycle that contains a fluorophore. As a result, this reaction was used as the basis for a new, selective and sensitive fluorescence system for the recognition of hypochlorite. The effectiveness of the method was demonstrated by its use to detect hypochlorite in a disinfectant solution as well as to image hypochlorite in cells.
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http://dx.doi.org/10.1039/c6tb01392aDOI Listing
August 2016

Turn-On Near-Infrared Fluorescent Sensor for Selectively Imaging Serotonin.

ACS Chem Neurosci 2016 Jan 31;7(1):21-5. Epub 2015 Oct 31.

Department of Chemistry, University of Missouri , Columbia, Missouri 65211, United States.

A molecular imaging tool that provides for the direct visualization of serotonin would significantly aid in the investigation of neuropsychiatric disorders that are attributed to its neuronal dysregulation. Here, the design, synthesis, and evaluation of NeuroSensor 715 (NS715) is presented. NS715 is the first molecular sensor that exhibits a turn-on near-infrared fluorescence response toward serotonin. Density functional theory calculations facilitated the design of a fluorophore based on a coumarin-3-aldehyde scaffold that derives from an electron-rich 1,2,3,4-tetrahydroquinoxaline framework, which provides appropriate energetics to prevent the hydroxyindole moiety of serotonin from quenching its fluorescence emission. Spectroscopic studies revealed that NS715 produces an 8-fold fluorescence enhancement toward serotonin with an emission maximum at 715 nm. Accompanying binding studies indicated NS715 displays a 19-fold selective affinity for serotonin and a modest affinity for catecholamines over other primary-amine neurotransmitters. The utility of NS715 toward neuroimaging applications was validated by selectively labeling and directly imaging norepinephrine within secretory vesicles using live chromaffin cells, which serve as a model system for specialized neurons that synthesize, package, and release only a single, unique type of neurotransmitter. In addition, NS715 effectively differentiated between cell populations that express distinct neurotransmitter phenotypes.
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http://dx.doi.org/10.1021/acschemneuro.5b00235DOI Listing
January 2016

Tunable Molecular Logic Gates Designed for Imaging Released Neurotransmitters.

Chemistry 2015 Aug 26;21(32):11446-51. Epub 2015 Jun 26.

Department of Chemistry, University of Missouri, 601 S. College Ave. Columbia, MO 65211 (USA).

Tunable dual-analyte fluorescent molecular logic gates (ExoSensors) were designed for the purpose of imaging select vesicular primary-amine neurotransmitters that are released from secretory vesicles upon exocytosis. ExoSensors are based on the coumarin-3-aldehyde scaffold and rely on both neurotransmitter binding and the change in environmental pH associated with exocytosis to afford a unique turn-on fluorescence output. A pH-functionality was directly integrated into the fluorophore π-system of the scaffold, thereby allowing for an enhanced fluorescence output upon the release of labeled neurotransmitters. By altering the pH-sensitive unit with various electron-donating and -withdrawing sulfonamide substituents, we identified a correlation between the pKa of the pH-sensitive group and the fluorescence output from the activated fluorophore. In doing so, we achieved a twelvefold fluorescence enhancement upon evaluating the ExoSensors under conditions that mimic exocytosis. ExoSensors are aptly suited to serve as molecular imaging tools that allow for the direct visualization of only the neurotransmitters that are released from secretory vesicles upon exocytosis.
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http://dx.doi.org/10.1002/chem.201501379DOI Listing
August 2015

Coumarin-3-aldehyde as a scaffold for the design of tunable PET-modulated fluorescent sensors for neurotransmitters.

Chemistry 2014 Dec 24;20(52):17488-99. Epub 2014 Oct 24.

Department of Chemistry, University of Missouri, Columbia, MO 65211 (USA).

NeuroSensor 521 (NS521) is a fluorescent sensor for primary-amine neurotransmitters based on a platform that consists of an aryl moiety appended to position C4 of the coumarin-3-aldehyde scaffold. We demonstrate that sensors based on this platform behave as a directly linked donor-acceptor system that operates through an intramolecular acceptor-excited photoinduced electron transfer (a-PET) mechanism. To evaluate the PET process, a series of benzene- and thiophene-substituted derivatives were prepared and the photophysical properties, binding affinities, and fluorescence responses toward glutamate, norepinephrine, and dopamine were determined. The calculated energy of the highest occupied molecular orbital (EHOMO ) of the pendant aryl substituents, along with oxidation and reduction potential values derived from the calculated molecular orbital energy values of the platform components, allowed for calculation of the fluorescence properties of the benzene sensor series. Interestingly, the thiophene derivatives did not fit the typical PET model, highlighting the limitations of the method. A new sensor, NeuroSensor 539, displayed enhanced photophysical properties aptly suited for biological imaging. NeuroSensor 539 was validated by selectively labeling and imaging norepinephrine in secretory vesicles of live chromaffin cells.
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http://dx.doi.org/10.1002/chem.201403128DOI Listing
December 2014

Three-input logic gates with potential applications for neuronal imaging.

J Am Chem Soc 2014 Apr 18;136(13):4877-80. Epub 2014 Mar 18.

Department of Chemistry, University of Missouri 601 South College Avenue, Columbia, Missouri 65211, United States.

Convenient methods for the direct visualization of neurotransmitter trafficking would bolster investigations into the development of neurodegenerative diseases. Here, tunable fluorescent molecular logic gates with applications to neuronal imaging have been developed. The three-input AND molecular logic gates are based on the coumarin-3-aldehyde scaffold and designed to give a turn-on fluorescence response upon the corelease of glutamate and zinc from secretory vesicles via exocytosis. Spectroscopic studies reveal an 11-fold fluorescence enhancement under conditions mimicking exocytosis. Methylation of the scaffold was used to optimize the spectral profile of the sensors toward desired excitation wavelengths. A binding study that elucidates the sensor-analyte interactions is presented. These sensors serve as a proof-of-concept toward the direct imaging of neurotransmitters released upon exocytosis using fluorescent molecular logic gates.
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http://dx.doi.org/10.1021/ja501211vDOI Listing
April 2014

A selective fluorescent chemosensor for phosphoserine.

Org Biomol Chem 2013 Nov;11(42):7387-92

Department of Chemistry, University of Missouri, 601 South College Avenue, Columbia, MO 65211, USA.

A fluorescent chemosensor for the detection of phosphoserine is reported. The ditopic sensor features a phosphate-coordinating zinc(II)-dipicolylamine (Zn(2+)-DPA) unit tethered to an amine-binding coumarin aldehyde fluorophore. With phosphoserine, the sensor demonstrates a 30-fold fluorescence enhancement under buffered aqueous conditions.
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http://dx.doi.org/10.1039/c3ob41677aDOI Listing
November 2013

ExoSensor 517: a dual-analyte fluorescent chemosensor for visualizing neurotransmitter exocytosis.

ACS Chem Neurosci 2013 Oct 14;4(10):1334-8. Epub 2013 Aug 14.

Department of Chemistry, University of Missouri-Columbia , 601 South College Avenue, Columbia, Missouri 65211, United States.

A dual-analyte fluorescent chemosensor (ExoSensor 517) for the direct visualization of neurotransmitters released upon exocytosis is presented. The sensor exploits the high concentration of neurotransmitters (e.g., glutamate, norepinephrine, and dopamine) and the pH gradient between the vesicle and synaptic cleft. The cooperative recognition elements require both binding and a change in environmental pH to afford a fluorescence response which makes ExoSensor 517 one of the first integrated molecular logic gates to be used for biological applications.
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http://dx.doi.org/10.1021/cn400128sDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799192PMC
October 2013

Selective catecholamine recognition with NeuroSensor 521: a fluorescent sensor for the visualization of norepinephrine in fixed and live cells.

ACS Chem Neurosci 2013 Jun 25;4(6):918-23. Epub 2013 Mar 25.

Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States.

A method for the selective labeling and imaging of catecholamines in live and fixed secretory cells is reported. The method integrates a tailored approach using a novel fluorescence-based turn-on molecular sensor (NeuroSensor 521) that can exploit the high concentration of neurotransmitters and acidic environment within secretory vesicles for the selective recognition of norepinephrine and dopamine. The utility of the method was demonstrated by selectively labeling and imaging norepinephrine in secretory vesicles such that discrimination between norepinephrine- and epinephrine-enriched populations of chromaffin cells was observed. This method was validated in fixed cells by co-staining with an anti-PNMT antibody.
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http://dx.doi.org/10.1021/cn300227mDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708293PMC
June 2013

Development of a fluorescent chemosensor for the detection of kynurenine.

Org Lett 2013 Jan 24;15(2):235-7. Epub 2012 Dec 24.

Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA.

Kynurenine, a metabolite of tryptophan, is known to contribute to cancer progression when overproduced. A method for facile fluorescent sensing of kynurenine using sensor 1 has been developed. When bound at low pH, sensor 1 undergoes a very large bathochromic shift because kynurenine extends the conjugation of the fluorophore. This unusual mechanism of activation provides a 390-fold fluorescence enhancement that is very specific to kynurenine and a wavelength of fluorescence that extends into the red.
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http://dx.doi.org/10.1021/ol303025mDOI Listing
January 2013

Molecular tubes for lipid sensing: tube conformations control analyte selectivity and fluorescent response.

J Org Chem 2012 Jan 10;77(2):851-7. Epub 2012 Jan 10.

Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA.

Two fluorescent sensors for lipids have been prepared and tested for detection of a number of hydrophobic compounds of varying shape and size. The data suggest that the two sensors have a different mode of fluorescent response. Yet, the two sensors are only different in the bridging group--one having a flexible amide and one having a rigid allyl bridge. The fluorescence data are explained based on a difference in conformation of the two sensors in aqueous solution.
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http://dx.doi.org/10.1021/jo201791aDOI Listing
January 2012

An indicator displacement assay with independent dual wavelength emission.

Tetrahedron Lett 2010 Jan;51(1):112-114

Department of Chemistry, 601 S. College Ave, University of Missouri, Columbia, MO 65211.

A multifunctional metallo-receptor was designed with both metal and boronic acid binding groups. A sensor ensemble was prepared using the metallo-receptor and the fluorescent dye ARS. The dye produced two distinct fluorescent bands from interaction with the boronic acid and the metal respectively. Partial displacement of the dye by simple analytes led to different fluorescent signatures than full displacement. This differential response provided easy discrimination of the individual analytes.
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http://dx.doi.org/10.1016/j.tetlet.2009.10.097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2801142PMC
January 2010

Interpenetrated nano-capsule networks based on the alkali metal assisted assembly of p-carboxylatocalix[4]arene-O-methyl ether.

Chem Commun (Camb) 2008 Mar 19(12):1410-2. Epub 2008 Feb 19.

Department of Chemistry, University of Missouri-Columbia, 601 S. College Avenue, Columbia, MO 65211, USA.

Reaction of p-carboxylatocalix[4]arene-O-methyl ether with either rubidium or caesium hydroxide results in the formation of interpenetrated nano-capsule networks with the calixarene in the 1,3-alternate conformation.
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http://dx.doi.org/10.1039/b716777fDOI Listing
March 2008

Shape-selective fluorescent sensing ensemble using a tweezer-type metalloreceptor.

Org Lett 2006 May;8(10):2163-6

Department of Chemistry, University of Missouri-Columbia, 65211, USA.

[reaction: see text] A fluorescent sensing ensemble for pyridine-derived compounds is described. The receptor portion of the ensemble is prepared from a bisimidazole pyridine which coordinates copper to form a well-defined cavity. Small heteroaromatic guests such as adenine bind strongly in the cavity. The fluorescent response is provided by a dye which is coordinated to the receptor and quenched by the metal ion. The dye is released upon guest binding providing up to 25-fold fluorescence increases.
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http://dx.doi.org/10.1021/ol060641kDOI Listing
May 2006

Selective amine recognition: development of a chemosensor for dopamine and norepinephrine.

Org Lett 2004 Oct;6(21):3727-30

Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA.

[reaction: see text] A boronic acid-containing coumarin aldehyde was designed and synthesized. The sensor binds to catecholamines such as dopamine and norepinephrine by forming an iminium ion with the amine as well as a boronate ester with the catechol. An internal hydrogen bond produces a colorimetric response to these analytes with good selectivity for catecholamines over simple amines. The fluorescence of the sensor is quenched by the catechol.
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http://dx.doi.org/10.1021/ol048625fDOI Listing
October 2004

Shape-selective sensing of lipids in aqueous solution by a designed fluorescent molecular tube.

J Am Chem Soc 2004 Oct;126(40):12732-3

Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.

The design, synthesis, and recognition properties of two isomeric calixnaphthalene-type molecular tubes is described. The anti isomer showed strong fluorescence quenching upon titration with various simple lipid guests in water, in which the more hydrophobic guests associated with higher affinity. The syn isomer bound long straight-chain guests tightly with a similar fluorescence-quenching response. However, the syn isomer was more selective, giving an increase in fluorescence upon titration of guests which could not thread through the tube. Thus, the syn isomer is a selective fluorescent sensor for long straight-chain lipids.
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http://dx.doi.org/10.1021/ja047639dDOI Listing
October 2004

Detection of amines and unprotected amino acids in aqueous conditions by formation of highly fluorescent iminium ions.

J Am Chem Soc 2003 Dec;125(52):16174-5

Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.

Properly substituted coumarin aldehydes can be used to detect amines and amino acids under neutral, high ionic strength conditions by the formation of highly fluorescent iminium ions. The fluorescence of one sensor increases by 26-fold upon the addition of glycine. This strong florescent response is attributed to hydrogen bonding of the chromophore carbonyl by the acidic iminium proton.
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http://dx.doi.org/10.1021/ja036434mDOI Listing
December 2003

Evidence for hydrogen abstraction from C1 of taurine by the high-spin Fe(IV) intermediate detected during oxygen activation by taurine:alpha-ketoglutarate dioxygenase (TauD).

J Am Chem Soc 2003 Oct;125(43):13008-9

Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.

The Fe(II)- and alpha-ketoglutarate-dependent dioxygenases catalyze hydroxylation reactions of considerable biomedical and environmental significance. Recently, the first oxidized iron intermediate in the reaction of a member of this family, taurine:alpha-ketoglutarate dioxygenase (TauD), was detected and shown to be a high-spin, formally Fe(IV) complex. The demonstration in this study that decay of the Fe(IV) complex is approximately 30-fold slower when it is formed in the presence of 1-[2H]2-taurine provides evidence that the intermediate abstracts hydrogen from C1, the site of hydroxylation, and suggests that quantum-mechanical tunneling may contribute to C1-H cleavage.
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http://dx.doi.org/10.1021/ja037400hDOI Listing
October 2003

A rigid cavity containing tetra-cobalt(III) [2 x 2] grid complex.

Chem Commun (Camb) 2003 Feb(3):336-7

Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA.

The synthesis and structure of a rigid, cavity containing tetra-cobalt(III) [2 x 2] grid complex using an unusual bis(bipyridine)dimethoxynaphthyridine ligand is described.
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http://dx.doi.org/10.1039/b207039aDOI Listing
February 2003

Selectivity via cooperative interactions: detection of dicarboxylates in water by a pinwheel chemosensor.

J Org Chem 2002 Aug;67(17):6113-6

Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.

The recognition properties of a cooperative pinwheel chemosensor for dicarboxylates are described. The sensor possesses four guanidinium recognition elements to cooperatively bind two dicarboxylates of varying size. The effect of cooperativity and the read-out mechanism contributes to favorable binding constants for dicarboxylates in water, as well as a high degree of selectivity over monocarboxylates. Appropriate methods of reporting affinity for cooperative systems are discussed.
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http://dx.doi.org/10.1021/jo025903kDOI Listing
August 2002

Synthesis of 3,5- and 3,6-linked calix[n]naphthalenes.

J Org Chem 2002 Feb;67(3):904-9

Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.

The preparation of calix[n]naphthalenes from derivatives of 2,7-dihydroxynaphthalene is described. 1,8-Dialkyl substitution is used to direct the regiochemistry of the acid-catalyzed condensation reactions. Acyclic peri substituents lead to a 3,5-linked calix[3]naphthalene, whereas cyclic peri substituents give predominantly a calix[5]naphthalene with the corresponding 3,6-linkage. The 3,6-linked calix[4]naphthalene is prepared in pure form by a dimerization strategy.
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http://dx.doi.org/10.1021/jo0161173DOI Listing
February 2002