The emphasis of this work has been in two areas of optical materials - the
crystal-chemical development of new optical frequency converters and the synthesis
and study of new hosts for Cr³⁺ luminescence and lasing.
A simple method has been developed to identify promising frequency-doubling
materials containing triangular oxoanions by...
In spite of their importance in many systems, liquid surfaces have been
explored at the microscopic level to a much lesser extent than solids. Most surface
analysis must take place in vacuum, a major drawback for liquids. The technique of
time-of-flight scattering and recoil spectrometry (TOF-SARS) has been applied to...
Fusion reactions with radioactive neutron-rich projectiles have been the subject of much recent theoretical and experimental interest. Predictions of enhancement of the cross section due to the use of a neutron-rich projectile may have implications for synthesis of heavy nuclei. In this work, the fusion-fission excitation functions were measured for...
Polyhalogenated benzenes have been analyzed by standard electron capture
chemical ionization mass spectrometry (ECCI/MS), and electron monochromator mass
spectrometer (EM/MS) systems. The EM/MS experiments distinguished electronegative
compounds (especially isomers) by transient negative ions (TNIs) of the same mass but
differing energies and/or the formation of distinct TNIs of different masses...
An asymmetric approach to the synthesis of byssochlamic acid (1) is
described. Regioisomeric enzymatic differentiation is described in the selective
hydrolysis of dimethyl ester 30 by porcine liver esterase. Chiral dimethyl ester 42
was prepared by desymmetrization of cyclopentene 34 using porcine liver
esterase. A key intramolecular [2+2]cycloaddition-cycloreversion
photometathesis of...
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...
Rapamycin (5) was isolated in 1975 from the soil bacteria Streptomyces hygroscopicus and its structure was determined from spectroscopic techniques and an x-ray crystallographic analysis. Although it was initially found to exhibit antibiotic activity, it was subsequently shown to possess potent immunosuppressive activity as well.
Three approaches to the synthesis...
A three part study involving aspects of radical properties of various
aromatic species was accomplished.
Experiments to ascertain the importance of geometric and electronic
effects on the intramolecular transfer of a pi-complexed radical to a terminal double bond
was performed. Several 4-aryl-1-butenes were reacted in competition with 1-undecene
with a...
2,5-dihydroxyacetanilide epoxidase from Streptomyces LL-C10037 (DHAE I)
catalyzes the epoxidation of hydroquinone 4, to form epoxyquinone 7. DHAE I has been
purified to homogeneity, with an overall purification factor greater than 23,000. N-terminal
and internal amino acid sequences have been obtained from the purified enzyme so
that the epoxidase gene...
Linear alkylbenzenesulfonate (LAS) is the most widely used anionic surfactant in
commercial detergent formulations. The environmental fate of LAS is of interest because
of its disposal to wastewater treatment facilities and subsequent occurrence as a
micropollutant in surface waters and groundwater. While LAS fate in wastewater
treatment systems and surface...
The interactions of a model synthetic liquid fuel reactant (furan) with a model
hydrodeoxygenation catalyst (clean and sulfided single crystal molybdenum)
were investigated using the following UHV tools: Auger electron spectroscopy
(AES), low energy electron diffraction (LEED), and temperature programed
reaction spectroscopy (TPRS). In addition to furan, the reactions of...
A new experimental apparatus was built at Oregon State University to perform high resolution stimulated Raman spectroscopy in a pulsed molecular jet at state densities of the order of 10¹¹ cm⁻³. The technique uses a stimulated Raman step to first populate a vibrational/rotational level and then a resonantly enhanced multiphoton...
An atmospheric pressure argon glow discharge is shown
to detect trace levels of carbohydrates in aqueous flowing
systems, using either of two glow discharge solution
interface configurations. The first configuration consists
of an oscillating glow discharge sustained between a flowing
aqueous cathode and platinum anode. Picomole and micromolar
mass and...