Current studies suggest that perfluorinated organic compounds, such as fluorotelomer alcohols (FtOHs) in the troposphere, may be precursors of perfluorocarboxylic acids and perfluorosulfonates in remote regions. Fluorinated organic compounds were investigated in archived extracts collected from remote locations in Okinawa, Japan (HSO) and Mount Bachelor, Oregon (MBO) during the springs...
The general emphasis of this work has been synthesis, characterization, and applications of n- and p-type inorganic oxide thin films that are deposited from solutions. In particular, a study of n-type transparent semiconductor films of tin (IV) oxide and zinc-doped tin (IV) oxide has been performed by spin coating. Solution...
The purpose of this investigation was to determine the nature of the extractives from red alder bark in an effort to discover the materials which cause the red stain in red alder wood. Samples of bark and wood were obtained and successively extracted with hexane, benzene, ether, ethanol, and hot...
The purpose of this research was to compare four different media that were used to monitor SOC atmospheric concentrations in remote ecosystems. The accumulation of semi-volatile organic compounds, including pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), was investigated in lichen, 2-year old conifer needles, resin-based passive air sampling...
An intramolecular variant of the modified-Julia olefination was demonstrated by the synthesis of α,β-unsaturated lactones in a mild and (Z)-selective fashion. The lynchpin reagent (benzothiazol-2-sulfonyl) acetic acid was synthesized in a straightforward fashion in 86% overall yield from commercially available 2-mercaptobenzothiazole via conversion to ethyl (benzothiazol-2-ylthio)acetate by base mediated alkylation...
The synthesis of 3,3'-diphenylbenzopinacol was carried out both by means of the Grignard reaction between m-diphenyl magnesium iodide and benzil, and by reduction of m-phenyl benzophenone. The pinacol was rearranged and the products analyzed. The migration aptitude of m-biphenyl was determined to be 1.5. Attempts to prepare 3,3'-diphenyl-4,4'-dimethylbenzopinacol were unsuccessful....
A sensitive, selective, rapid analytical method based on large-volume injection (LVI)
liquid chromatography/ tandem mass spectrometry was developed using
commercially-available hardware that eliminates the need for either off-line or on-line
solid phase extraction. Centrifugation followed by the direct injection of 1,800 µL
was used for the quantification of illicit drugs,...
Many D2d-symmetric 2,2',6,6'-tetrasubstituted biphenyls are
readily prepared via net oxidative dimerization of appropriate
1,3-disubstituted benzenes. Conversion of such proprochiral
compounds to useful C2-symmetric chiral biphenyls requires
formal replacement of two substituents on opposing aryl ring
units with alternate groups. This under exploited
desymmetrization tactic has been demonstrated for the
generation...
The concentration of chlorophyll in natural bodies of water is
commonly determined as a means to rapidly estimate the phytoplankton
biomass. The literature gives numerous warnings, however, as to the
problems involved with accurately determining chlorophyll
concentrations. The author's work at Crater Lake, Oregon enticed him
to explore critically the...
In previous work (Blakemore et al. Org. Lett. 2005, 7, 4721; Heterocycles 2006, 70, 609), successful elaborations of the lupine alkaloids (±)-α-isosparteine (dl-2) and (±)-β-isosparteine (dl-3) were realized from a common tetraoxobispidine precursor, 3,7-diallyl -2,4,6,8-tetraoxo-3,7-diazabicyclo[3.3.1]nonane (93). Herein, the tetraoxobispidine approach to lupine alkaloids was extended to a total synthesis of...
Catalysis of the racemizationof optically active phenyl
benzenethiolsulfinate, (+)-I, by (a) methylthioacetic acid (II) and (b)
a -methylthio-m-toluic acid (III) has been investigated in aqueous
dioxane and anhydrous acetonitrile at 39.6°C. Added II did not cause
any increase in the rate of racemization of (+)-I in either solvent. In
aqueous...
A novel method for detecting the peptidase activity of clinically relevant peptidases was investigated using solid-contact electrochemical polyion sensors under chronopotentiometric control. Complete instrumental control over ion-extraction was accomplished by incorporating a lipophilic electrolyte into the ion-selective membrane; the sensors had no intrinsic ion-exchange capabilities. The sensors were used to...
This research was undertaken to develop a sensitive, selective, and rapid analytical method to measure ethyl glucuronide (EtG) and ethyl sulfate (EtS) in urine as urinary biomarkers of alcohol exposure. Large-volume injection (LVI) coupled with liquid chromatography / electrospray tandem mass spectrometry was used to eliminate the need for either...
Effective methods for the enantiopure formation of substituted piperidine rings are significantly important due to their presence in alkaloid products. A valuable method to form these ring systems would be via an intramolecular heteroatom Michael addition from the corresponding enone or enal. Described herein is a methodolgy that has been...
The nuclear reaction ¹⁰⁰Mo(¹²⁴Sn,xn)[superscript 224-x]U has been carried out at E[subscript cot] of 578 MeV and 634 MeV using the facilities and equipment at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL) in order to initiate the search for the inverse fission of uranium. Reference...
The work described herein details the synthesis and application of
biphenyls that probe the effects of hydrogen, Cl / Br, and methyl substituents
on the aryl ring of the terminal acetylenic carbon. From this work, we
successfully developed the rapid synthesis of phenyl acetylenes in 3-4 steps
from inexpensive commercially...
Halogenated Polycyclic Aromatic Hydrocarbons (X-PAHs) are ubiquitous contaminants that are thought to be generated by processes such as chemical industries and incomplete combustion, including waste incineration and electronic waste (e-waste) burning. X-PAHs are a concern for environmental and human health because they are toxic, mutagenic, and are expected to be...
Benzylsuccinate (BSA), methylbenzylsuccinate (methylBSA), and ethylbenzylsuccinate (ethylBSA) are unambiguous anaerobic biotransformation products from toluene, xylenes, and ethylbenzene decay, respectively, and may be used to indicate intrinsic bioremediation is occurring at hydrocarbon-contaminated sites. In order to improve upon current methods that detect and quantify anaerobic hydrocarbon metabolites in field samples, solid-phase-extraction...
The 3-substituded indolic enamide moiety has been found in many marine compounds over the past 20 years. These indolic enamides exhibit various biological properties such as cytotoxic, anthelmintic, antimicrobial and HW-inhibitory activities. Among these indolic enamides, some are (E)-enamides, like coscinamide A and coscinamide B, others are (Z)-configuration in their...
Over the last decade, the use of highly branched macromolecules, called dendrimers, is emerging. Polyamidoamine (PAMAM) dendrimers, in particular, have attracted high interest due to their unique properties, such as well-defined size, shape, and solubility in water. Our group, as part of an interdisciplinary team, is currently working on developing...
The transport and deposition of airborne contaminants, including semivolatile
organic compounds (SOCs), to high elevation ecosystems is
recognized as a potential threat to these ecosystems. The objectives of
this research were to develop an analytical method to measure a wide
range of SOCs in high elevation lake sediment and to...
Chlorinated aliphatic hydrocarbons (CAHs) such as vinyl chloride (VC) and 1,-2 dichioroethane (DCA), are wide-spread groundwater pollutants found at many contaminated field sites around the world. Quantitative tools are needed to determine the in situ rates of VC and DCA transformation to ethene in contaminated groundwater. The objective of this...
Resonance Electron Capture Mass Spectrometry (REC-MS) is a sensitive
experimental technique for the study of gas-phase compounds with positive electron
affinity. This technique was used to study a class of compounds known as
baloetbylenes containing chlorine and bromine substitutions. Haloetbylenes are an
important class of compounds because ethylene is the...
Capillary electrophoresis as a technique has many applications in a broad range of fields including forensics, environmental analysis, and biological analysis and as a separation method for samples such as oligonucleotides, peptides, proteins, and pharmaceuticals. The research conducted herein is for the antibiotic pharmaceutical ciprofloxacin HCl and three impurities. Sample...
Two improvements to the established procedures for synthesis and response detection of ion-selective optical sensors (optodes) were introduced.
The first improvement addresses the drawback of organic dye (optode-localized chromoionophore) photobleaching. This positively impacts fluorescence response and allows for (1) direct measurement of hydrogen ion activity upon binding with the dye,...
The aqueous chemistries of two transition metal cations, Zr⁴⁺ and Nb⁵⁺, are examined and then used to develop inorganic precursor solutions. The oxides of these cations (ZrO₂ and Nb₂O₅) are deposited and characterized, and their morphological and optical properties discussed. Due to the obstacles created by niobium's aqueous chemistry, an...
Neurofilament proteins are intermediate filaments found in the neuronal cytoskeleton. Phosphorylation of these proteins is considered important for the assembly and stability of the filaments. Accurate molecular weights have been difficult to measure, largely because the high degree of phosphorylation results in M[subscript r]'S that are significantly greater than dictated...
The rate of removal of benzene, toluene, ethylbenzene and the xylene isomers (BTEX) from contaminated groundwater is needed to design remediation processes. Benzylsuccinic acid (BSA) and methyl-benzylsuccinic acid (methyl BSA) are unambiguous metabolites of anaerobic BTEX biodegradation. An analytical method for quantitative determination of BSA in groundwater samples was developed....
The epoxide deoxygenation reaction is formally the reverse of theepoxidation reaction. Compared to epoxidation, which has reached its fullmaturity, epoxide deoxygenation has not been as intensively developed.Among the few deoxygenation reagents, a handful are catalytic in a metalcomplex, show high stereospecificity and operate under mild conditions. Acommon feature of all...
The rhenium (V) complex Tp'ReO₂ (Tp' = hydrido-tris-(3,5-
dimethylpyrazolyl)borate), generated in situ from PPh₃ reduction of
Tp'Re0₃, reacts with small ring heterocycles such as epoxides and
episulf ides. The strained trans-cyclooctene ring provides an unusual
thermodynamic bias against direct atom transfer, but trans-cyclooctene
oxide still produces substantial amounts of trans-cyclooctene....
Ambient high-volume (hi-vol) air samples were collected between March 15th and May 30th 2002, at Cheeka Peak Observatory (CPO), located on the tip of the Olympic Peninsula, Washington State. This sampling campaign was in conjunction with the 2002 Inter-Continental Transport and Chemical Transformation (ITCT 2K2) Campaign and the Photochemical Ozone...
Azaspiracid-1, a novel marine toxin that contains 9 rings and 20 stereogenic centers, has drawn considerable attention from synthetic groups worldwide due to its structural complexity, which includes a unique trioxabisspiroketal fused to a tetrahydrofuran ring (ABCD rings), a piperidine-tetrahydrofuran spiroaminal system fused to a 2,9-dioxabicyclo[3.3.1]nonane system (FGHI rings), a...
The rhenium dithiodiolate, Hydrido-tris-(3 ,5-dimethyl- 1 -pyrazol yl) borato(ethane- 1 ,2-dithiodiolato)(oxo)rheni um(V), and Hydrido-tris-(3 ,5-dimethyl- 1 -pyrazolyl)borato(phenylethanedithiodiolato)(oxo)rhenium(V), were synthesized by reductive cyclocondensation of alkane-1,2-dithiols with Tp'Re0₃ in a one pot fashion. The rhemium monothiodiolate, Hydrido-tris-(3 ,5-dimethyl- 1 -pyrazolyl) borato(ethane- 1 ,2-monothiodiolato)(oxo)rhenium(V), and Hydrido-tris-(3 ,5- dimethyl- 1 -pyrazolyl)borato(propanemonothiodiolato)(oxo)rhenium(V), were also synthesized...
Two nonlinear optical experiments are presented in which the third-order electronic susceptibility of molecules is used to generate Raman signals. The first one uses a single 532 nm beam from a Nd:YAG laser to produce Stimulated Raman Scattering in benzene and deuterated benzene. With a simple experimental set-up, stimulated emission...
A direct purge technique was developed for the determination of chloroform or trichloroethylene (TCE) in water samples. These volatile organic solvents are transferred from the water sample to a reagent where they are trapped and react to form products (Fujiwara chemistry) that are monitored fluorometrically. Chloroform in a water sample...
An analytical technique has been developed for the determination of methylmercury compounds in environmental samples. The technique is based on a two-stage procedure. In the first stage, methylmercury compounds are isolated from the sample matrix as methylmercury chloride (MeRgCl) by distillation. The distillation procedure is based on a series of...
A new approach to the discovery of high absorbing semiconductors for solar cells was taken by working under a set of design principles and taking a systemic methodology. Three transition metal chalcogenides at varying states of development were evaluated within this framework. Iron pyrite (FeS₂) is well known to demonstrate...
A new approach towards a total synthesis of paeoniflorigenin is discussed. The approach involves the application of regio- and stereoselective [2+2] photocycloaddition for the preparation of a key intermediate, cyclobutanone 86, and model studies on diiodosamarium (Sm12) mediated pinacol coupling of a diketone. Intermolecular [2+2] photocycloaddition of a,13unsaturated lactam 33...
The carbon is photoelectron spectrum of CO₂ has been measured with very high photon energy resolution. The natural lifetime of the carbon is hole state has been determined from a series of spectra taken at photon energies of 308, 320, and 330 eV. The measured values of the lifetimes show...
Regiochemistry of intramolecular [2+2] photocycloadditions of oxygenated
6-alkenyl-3-alkoxy-2-cyclohexenones is studied. Application of this methodology
to construct a key intermediate [3.3.2] bicyclic skeleton of ryanodol is described
as well. Irradiation of (3-butenyl)compounds 3, 11, 14 and of (4-pentenyl)compound 6 afforded exclusively the linear photoadducts 4, 12, 15 and
7 respectively. Irradiation...
At Site-300, Lawrence Livermore National Laboratory (LLNL), CA,
trichloroethene (TCE) is present along with tetraalkoxysilanes such as tetrabutoxysilane
(TBOS) and tetrakis(2-ethylbutoxy) silane (TKEBS), as subsurface contaminants.
Intrinsic transformation of TCE to cis-dichloroethene (c-DCE) was observed in the
groundwater at locations co-contaminated with TBOS or TKEBS. Attenuation of TBOS
and TKEBS...
The electronegativities of -SF₅, -CF₃SO₂, and -SO₂F have been measured with gas phase X-ray photoelectron spectroscopy. Of these three groups previously measured values were found only for -SF₅. The electronegativities of -Cl, -Br, -CF₃, and -CF₃, were concurrently measured to determine how the findings of this research compare with other...
The migration of chloride ions in concrete with steel reinforcement under cathodic protection was investigated. Mortar blocks (15 cm x 15 cm x 17 cm) of various composition (water to cement ratio, chloride ion content) were cast with an iron mesh cathode embedded along one face and a thermally sprayed...