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Classification of explosives. Period covered: January--March 1976. Normal process development endeavor No. 216. [Transportation hazards]

Description: Sufficient supplies were purchased to test ten explosives using the NOL Card Gap Test as described in Department of the Army Technical Bulletin TB 700-2 (Explosives Hazard Classification Procedures) dated 19 May 1967. A calibration series was fired using pressed TNT (density = 1.626 Mg/m/sup 3/). The estimated 50 percent point was 158 cards.
Date: January 1, 1976
Creator: West, G. T.
Partner: UNT Libraries Government Documents Department

Preconversion processing of bituminous coals: New directions to improved direct catalytic coal liquefaction. [Effect of preconversion heat soak with coal liquids]

Description: A study of the high-temperature soaking started in this quarter, following the installation of reactors in the previous quarter. Two high-volatile bituminous coals and three coal liquids, which were identified in the previous report, were used. A cross-linked, three-dimensional macromolecular model has been widely accepted f or the structure of coal, but there is no direct evidence to prove this model. The conventional coal structure model has been recently re-examined by this investigator because of the importance of relatively strong intra- and intermolecular interactions in bituminous coals. It was reasonable to deduce that significant portions were physically associated after a study of multistep extractions, associative equilibria, the irreversibility and the dependence of coal concentration on solvent swelling, and consideration of the monophase concept. Physical dissociation which may be significant above 300{degree}C should be utilized for the treatment before liquefaction. The high-temperature soaking in a recycle oil was proposed to dissociate coal complexes.
Date: July 1, 1992
Partner: UNT Libraries Government Documents Department

High temperature syntactic foam

Description: Resins from the polyimide, polybenzimidazole polyamide-imide, phenolic, silicone, and urethane families were formulated with glass microbubbles and carbon microspheres to produce low density, high strength syntactic foams. The polyimide and polybenzimidazole foams were the most thermally stable, but even the urethane exceeded the design goals. Foams with high and low thermal conductivity were developed and their material properties were measured. The low conductivity was achieved using glass microbubble fillers and high conductivity was achieved using carbon microsphere fillers.
Date: July 1, 1977
Creator: McIlroy, H. M.
Partner: UNT Libraries Government Documents Department

Mechanisms for radiation damage in DNA constituents and DNA: reactions of the N/sub 1/-substituted thymine. pi. -cation radicals

Description: Reactions of the N/sub 1/-substituted thymine ..pi..-cation radicals were investigated by ESR in several aqueous glasses. In 8M NaOD (NaOH) spectra suggestive and OD/sup -/(OH/sup -/) addition to position 6 in the ..pi..-cations of 1-methylthymine, and thymidine were found immediately after uv photolysis at 77/sup 0/K. Production of the same radicals by electron attachment to 1-methyl-5-bromo-6-hydroxythymine, and 5-bromo-6-hydroxythymidine in 8M NaOD confirms the OD/sup -/ addition mechanism. Results found for these brominated compounds in 12M LiCl (D/sub 2/O) after electron attachment show that the ..cap alpha../sub 6/ (H) splitting was sensitive to changes in substituents at position 1 as well as changes in environment. This variation in splitting is shown to be accounted for by small conformational changes in the radicals. In 8M NaClO/sub 4/ ..pi..-cations of the substituted thymines gave evidence for both deprotonation and OD- addition.
Date: January 1, 1977
Creator: Sevilla, M. D. & Engelhardt, M. L.
Partner: UNT Libraries Government Documents Department

Bibliography of mass spectroscopy literature for 1973 compiled by a computer method. Bibliography and author index. [About 8,000 citations]

Description: This report covers the year 1973, and lists approximately 8,000 articles of interest to mass spectroscopists. This report consists of three sections, a Bibliography section, an Author Index section and a Key Word Out of Context Index (KWOC Index) section. The Bibliography section lists the authors, the title and the publication data for each article. The Author Index lists the authors' names and the reference numbers of their articles. The KWOC Index lists the key words, the reference numbers of the articles in which the key word appears and the first 100 characters of the title.
Date: June 1, 1976
Creator: Capellen, J.; Svec, H. J.; Sage, C. R. & Sun, R. (comps.)
Partner: UNT Libraries Government Documents Department

Molecular genetic and molecular evolutionary studies on the bacteriochlorophyll synthesis genes of Rhodobacter capsulatus

Description: Rhodobacter capsulatus, purple bacterium capable of either aerobic or photosynthetic growth, has proven to be very useful in genetic studies of photosynthesis. Forty-four genes clustered together within a 46 kilobase region are required to establish photosynthetic ability in R. capsulatus. Approximately twenty of these genes are involved in bacteriochlorophyll synthesis of which eight bch'' genes are the subject of this thesis. Six of these genes were found to code for the two ring reductases. The first converts protochlorophyllide (PChlide) into a chlorin, the immediate precursor to chlorophyll a, and then into a bacteriochlorin. Each reductase is shown to be made up of three subunits. PChlide reductase is coded by the genes bchN, bchB, and bchL. Proteins with amino acid sequences markedly similar to those of bchN and bchL have been shown in other organisms to be required for chlorophyll synthesis; hence, their designation as chlN and chlB. A third chloroplast-encoded gene of heretofore unknown function shares amino acid identities with bchB and is probably the third subunit of the plant PChlide reductase. The bchA locus, which encodes the chlorin reductase, is found to be made up of three separate, translationally coupled genes, referred to as bchX, bchY, and bchZ. Amino acid similarities between bchX, bchL, and the nitrogenase reductase protein nifH suggest that all three classes of proteins share certain three-dimensional structural features, including elements that are central to the enzymatic mechanism of nifH. PChlide reductase and chlorin reductase are clearly derived from a common ancestor. Several lines of analysis suggests the ancestor of both enzyme systems reduced PChlide twice to produce bacteriochlorophyll supporting the concept bacteriochlorophyll as the ancestral reaction center pigment.
Date: August 1, 1992
Creator: Burke-Agueero, D. H.
Partner: UNT Libraries Government Documents Department

Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries

Description: Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)
Date: June 1, 1992
Creator: Wahl, J. H.; Goodlett, D. R.; Udseth, H. R. & Smith, R. D.
Partner: UNT Libraries Government Documents Department

NMR analysis of the Kel-F co-polymer system. Period covered: July--September 1976

Description: Dimethylacetamide solutions of several members of the Kel-F polymer system were analyzed by /sup 19/F NMR spectrometry. Although relatively acceptable spectral data are obtained, the mandatory methods of analysis for this type of system, such as reliable peak integration data and data time averaging, are not possible with the limited lock mode sweep range of the Varian HA-100 (1500 Hz). The possibility of electronic modification of the unit for the purpose of increasing the lock mode sweep range to cover the /sup 19/F spectral range is being studied.
Date: January 1, 1976
Creator: Clink, G. L.
Partner: UNT Libraries Government Documents Department

Continental shelf processes effecting the oceanography of the South Atlantic Bight. Hydrography of Onslow Bay, North Carolina: September 1975 (OBIS II). Progress report

Description: Over the course of OBIS II, 3-14 September, two intrusion cores were observed. One was apparently trapped nearshore over much of the study period, but as time went on, it either dissipated, moved too far shoreward or moved too far laterally along the shelf to be detected by the existing observational grid. The other (later) intrusion was first detected on 5-7 September and was observed to be moving into the Bay from the southeast over the remainder of the study period. Plots of the horizontal temperature and salinity distribution were suggestive of these phenomenon by means of the higher salinity-lower temperature relationship. However, the real confirmation rests in the vertical distributions of sigma-t and chlorophyll presented in conjunction with the Bio and Hydrogrids, and the T--S plot which reveals slope waters on the shelf. The intruded waters were not of low enough temperature to carry high nutrient concentrations onto the shelf for study. However, the general results of this study tend to confirm the view that our basic grid array and methods are compatible with measurement of the processes we initially set out to study. Analyses of these data relative to the current meter data will allow a nearly complete description of the Onslow Bay system during the observational period.
Date: March 12, 1976
Creator: Atkinson, L P; Singer, J J; Dunstan, W M & Pietrafesa, L J
Partner: UNT Libraries Government Documents Department

Trichloronitrosobenzene: a raw material for TATB synthesis

Description: In the usual synthesis of s-triaminotrinitrobenzene (TATB), s-trichlorobenzene (TCB), is first nitrated to s-trichlorotrinitrobenzene (TCTNB) and then aminated with ammonia. The s-TCB is obtained as a byproduct from another synthesis operation or from 2,4,6-trichloroaniline. Isomerization of 1,2,4-trichlorobenzene is another possible source. Eastman Chemical Company (Kingsport, Tennessee) is a large producer of 2,4,6-trichloroaniline (TCA) which is used in the synthesis of photographic chemicals; however, they are unwilling to convert this to either the s-TCB or trichloronitrobenzene due to environmental concerns. They have proposed instead to convert TCA to 1,3,5-trichloro-2-nitrosobenzene in large quantity.
Date: July 1, 1977
Creator: Estes, Z. L.
Partner: UNT Libraries Government Documents Department

An EPR spin probe method for characterizing changes in the accessible regions of coal upon oxidation

Description: Eight Argonne Premium Coal Samples (APCS) were weathered in air and the structural and chemical changes that upon swelling with toluene and pyridine were, examined by an EPR spin probe method developed in this laboratory. Under mild oxidation conditions and swelling with toluene large structural changes were observed for lignite (Beulah-Zap) which suggested the collapse of the coal structure. This did not occur for higher rank coal. Upon oxidation and swelling with toluene and pyridine an increase occurred in the amino substituted spin probe concentration for coals with the carbon percent above 80%. A maximum was found for the creation of 5 {Angstrom} diameter pores upon swelling with pyridine at 85% C.
Date: January 1, 1992
Creator: Sady, W.; Kispert, L. D. & Spears, D. R.
Partner: UNT Libraries Government Documents Department

New methods and instrumentation for the characterization of biopolymers using electrospray ionization-mass spectrometry

Description: The technique of electrospray ionization (ESI) has significantly extended the ability to characterize large molecules by mass spectrometry. Proteins to at least 200,000 D can be transferred intact to the gas phase and molecular weights determined with precisions as high as 0.001% if individual charge states can be resolved. The ESI-MS can also serve as a near ideal interface and detector for capillary column separations providing a basis for highly efficient sample utilization. Using capillary electrophoresis (CE)-MS, injection quantities in the 10[sup [minus]18] mole range can be detected for smaller polypeptides using selected ion monitoring, and separation efficiencies as high as 5[center dot]10[sup 5] theoretical plates have been realized. We have recently shown that the use of small 5 [mu]m i.d. capillaries allows CE-MS with scanning detection for proteins for injection of 600 attomoles.
Date: September 1, 1992
Creator: Smith, R. D.; Udseth, H. R.; Rockwood, A. L.; Winger, B. E.; Hofstadler, S. A.; Goodlett, D. R. et al.
Partner: UNT Libraries Government Documents Department

ESR study of radiation damage in pyrimidines. Progress report, August 1, 1975--April 1, 1976

Description: The primary objective of this project is to develop general mechanisms for radiation damage to biomolecules using substituted pyrimidines as a model system. Results this year include a single crystal ESR study of 5-ethyl-5-isopropylbarbituric acid, development of the k-band microwave bridge, dose response measurements on methylated barbituric acid derivatives, and synthesis of several specifically deuterated uracil derivatives.
Date: April 1, 1976
Creator: Benson, B. W.
Partner: UNT Libraries Government Documents Department

Assessment of solvent extraction for treatment of coal gasifier wastewater. Progress report. [19 refs]

Description: A preliminary study has been completed for the assessment of solvent extraction for coal gasifier wastewater treatment. This study shows very favorable economics; wastewater contaminants have a market value of about $45.00 per 1000 gallons of water to be treated while treatment costs are about $1.25 to $2.50 per 1000 gallons. Measurements of distribution coefficients between water and various solvents has been completed for m-dihydroxybenzene (resorcinol) and is in progress for o- and p-dihydroxybenzene, pyridine, o-cresol, and naphthol. A very high distribution coefficient of 40 was found for m-dihydroxybenzene between water and octanone-2 (methyl heptyl ketone).
Date: June 1, 1977
Creator: Luecke, R. H.
Partner: UNT Libraries Government Documents Department

Investigation of metal hydrides using multiple wavelength neutron powder diffraction and the crystal structure determinations of the 2,4-dinitrophenylhydrazone derivative of 5-bromomethylidenecyclononanone and the 1-hydroxy-6-acetoxy-10. cap alpha. -bromo-bicyclo(4. 3. 1)deca-3-ene

Description: The problem of low neutron flux has been a major limitation in the study of both single crystals and powders by neutron diffraction. In general, for a conventional two-axis diffractometer the intensity of the neutron beam incident upon the sample is approximately three orders of magnitude less than the intensity of a typical x-ray beam used for diffraction studies. A method is described which, while not utilizing the entire neutron spectrum, can significantly increase the incident neutron flux without extensive equipment modifications (as would be required for time-of-flight techniques), and without any increase in beam size or decrease of resolution. The method can be applied to both single crystal and powder studies; however the description given applies only to the case of neutron powder diffraction. The discussion is restricted further to the case of elastic scattering. (JRD)
Date: June 1, 1977
Creator: DeHaven, P. W.
Partner: UNT Libraries Government Documents Department

Development of advanced NO[sub x] control concepts for coal-fired utility boilers

Description: All three of the CombiNO[sub x] NO[sub x] control technologies were performed simultaneously for the first time. Tests were performed while firing coal as the primary fuel, and natural gas and coal as reburn fuels. The results for the complete CombiNO[sub x] process for coal firing and natural gas reburning are displayed in Figure 3-1. NO/NO[sub x] measurements were taken with the new sample system. The filter and line were cleaned periodically throughout testing to avoid ash build-up; ash has also been shown to convert NO[sub 2] to NO. Reduction due to natural gas reburning was 54% with burnout air injected at a downstream location of approximately 1600[degree]F. Advanced Gas Reburning produced a 79% reduction -- although it is suspected that better reduction would have been possible if injection resolution in the furnace allowed the urea to be injected at a more optimum temperature of 1850[degree]F. The methanol injection step converted 45% of the existing NO to NO[sub 2], achieving an overall CombiNO[sub x] NO reduction of 89%. The coal reburning CombiNO[sub x] test results are displayed in Figure 3-2. Results are similar to those obtained for natural gas reburning. Reduction due to urea injection was better while reburning with coal than for natural gas, probably due to the more optimum urea injection temperature. The methanol injection step converted 40% of the NO to NO[sub 2], similar to the 45% NO conversion that occurred for natural gas reburning. An overall CombiNO[sub x] NO reduction of 93% was achieved, resulting in a final NO concentration of 61 ppM at 3% O[sub 2].
Date: September 15, 1992
Creator: Evans, A.; Pont, J. N.; England, G. & Seeker, W. R.
Partner: UNT Libraries Government Documents Department

(National Institute for Petroleum and Energy Research) quarterly technical report, April 1--June 30, 1992

Description: Progress reports are presented for the following two tasks: development of analytical methodology for analysis of heavy crudes; and thermochemistry and thermophysical properties of organic nitrogen- and diheteroatom-containing compounds. Objectives for task one are: to identify compounds or classes of compounds with significant positive or negative effects on crude oil and/or product properties and characteristics and to develop methods for their determination in conventional or low grade petroleum and syncrudes. Specific objectives for FY92 are: to determine catalytic cracking behavior of individual compound classes in petroleum; and to further develop GC/MS methodology for speciation of nitrogen and sulfur compound in petroleum. Objective for task two is to provide, interpret, and correlate with molecular structure and polarity of molecules, precise and accurate values of thermodynamic properties of organic nitrogen and diheteroatom-containing compounds that occur in or are readily derivable from heavy petroleum and oil shale. The results will enable the prediction of chemical equilibria for conceptual as well as current processes.(AT)
Date: August 1, 1992
Partner: UNT Libraries Government Documents Department

Origins of Circular Dichroism bands in Bowman--Birk soybean trypsin inhibitor

Description: The spectral properties of Bowman-Birk soybean trypsin inhibitor (BBI) were investigated by analyzing difference absorption spectra and difference circular dichroism (CD) spectra and by comparing them with those of tyrosyl model compounds. The O-acetylation of tyrosyl side chains showed that the ultraviolet CD bands of BBI above 225 nm originate from disulfide side chains and tyrosyl phenolic groups. A broad negative CD band centered around 280 nm in BBI arises mainly from disulfide bonds (epsilon/sub L/ - epsilon/sub R/ = -0.83 M/sup -1/cm/sup -1/ per disulfide). Each of two tyrosyl residues gives rise to negative CD at this region; together they contribute approximately 10 percent of the total CD intensity at 277 nm (epsilon/sub L/ - epsilon/sub R/ = -0.36 M/sup -1/cm/sup -1/ per tyrosyl). Disulfide bonds in BBI also have a broad positive CD band centered around 240 nm (epsilon/sub L/ - epsilon/sub R/ = 0.9 M/sup -1/cm/sup -1/ per disulfide). Tyrosyl side chains give rise to a sharp positive peak at 231 nm, overlapping with the positive disulfide CD. Dimerization of monomeric BBI did not alter the CD profile. Fully acetylated BBI has the near ultraviolet disulfide CD and the far ultraviolet polypeptide CD very similar to those of the native inhibitor, indicating that O-acetylation of two tyrosyl side chains did not induce much conformational change in BBI. The near ultraviolet CD of BBI was altered in the presence of 8 M urea or 6 M guanidine hydrochloride, with a greater change brought about by the latter. Dithiothreitol (20 mM) completely abolished the tyrosyl and disulfide CD in this region. (auth)
Date: January 1, 1975
Creator: Kay, E.
Partner: UNT Libraries Government Documents Department

Some recent aspects of relaxation line shapes in Moessbauer spectroscopy. [White noise approximation]

Description: Theoretical development in the line shape calculation of Mossbauer resonance spectra involving spin relaxation effects is introduced. The ''eigenvalue'' procedure of calculating line shapes saves computational times by two orders of magnitude compared to traditional methods. This was illustrated by calculating the relaxation spectra of hemoglobin cyanide and a GAMMA/sub 8/ quartet electronic state. The ''white noise approximation'' involved in all the relaxation theory is discussed, and its limitations are pointed out. The theory without such an approximation is used to analyze the data for Cs/sub 2/NaYbCl/sub 6/.
Date: January 1, 1977
Creator: Shenoy, G. K. & Dunlap, B. D.
Partner: UNT Libraries Government Documents Department

Kinetics and mechanism of desulfurization and denitrogenation of coal-derived liquids. Quarterly report, June 20, 1976--September 19, 1976

Description: Two high-pressure flow microreactors are functioning efficiently in studies of dibenzothiophene hydrodesulfurization and quinoline hydrodenitrogenation. Assembly of a third microreactor is scheduled for completion in about three months. Dibenzothiophene hydrodesulfurization at conditions such as 1,000 psig and 300-350/sup 0/C takes place in the absence of mass transfer influence. The rate is surprisingly high, requiring temperatures of 300/sup 0/C or less for determination of differential conversions with the existing apparatus. Batch reaction studies have shown that nitrogen removal from quinoline is characterized by an apparent activation energy of about 20 kcal/mole, whereas the rates of accompanying hydrogenation reactions are almost independent of temperature. Nitrogen removal from acridine and from carbazole is much slower than nitrogen removal from quinoline; the outer rings of the three ring compounds (acridine and carbazole) are hydrogenated relatively rapidly.
Date: October 1, 1976
Creator: Gates, B. C.; Katzer, J. R.; Olson, J. H.; Kwart, H. & Stiles, A. B.
Partner: UNT Libraries Government Documents Department

Ultrasensitive fluorescence detection of DNA

Description: We have shown that a number of polycationic highly fluorescent dyes form complexes with double-stranded DNA (dsDNA) which are stable to electrophoresis and have characterized in detail such dsDNA complexes with TOTO (1,1[prime]-(4,4,7,7-tetramethyl-4,7-diazaundecamethylene)-bis-4-[3-methyl-2,3-dihydro-(benzo-1,3-thiazole)-2-methylidene]-quinolinium tetraiodide) and oxazole yellow dimer (YOYO; an analogue of TOTO with a benzo-1,3-oxazole in place of the benzo-1,3-thiazole). TOTO and YOYO are virtually non-fluorescent in solution, but form highly fluorescent complexes with dsDNA, up to a maximum dye to DNA bp ratio of 1:4, with >1000-fold fluorescence enhancement. We have developed an assay using YOYO for the quantitation of single-stranded and dsDNA in solution applicable over a range of DNA concentrations from 0.5 to 100 ng per ml. The fluorescent dsDNA-dye complexes allow detection of dsDNA on agarose and acrylamide gels with picogram sensitivity. We have applied these complexes in multiplex mapping experiments for accurate sizing and quantitation of restriction fragments. We have shown that in gel shift experiments the stable dsDNA-dye complexes can be used to detect heteroduplex-Muts complexes with a sensitivity comparable to radioisotopic detection.
Date: January 1, 1992
Creator: Mathies, R. A. & Glazer, A. N.
Partner: UNT Libraries Government Documents Department

Toxicology and metabolism of nickel compounds. Progress report, December 1, 1974--November 30, 1975. [97433ONE]

Description: The toxicology and metabolism of nickel compounds (NiCl/sub 2/, Ni/sub 3/S/sub 2/, NiS, and Ni powder) were investigated in rats and hamsters. The new knowledge has included: demonstration that hyperglucagonemia is primarily responsible for the acute hyperglycemic effect of parenteral Ni(II) in rats; demonstration that parenteral injection of Ni(II) in rats produces acute nephropathy with proteinuria and amino aciduria, and with ultrastructural lesions of renal glomeruli and tubules; confirmation of the inhibitory effect of manganese upon the carcinogenicity of Ni/sub 3/S/sub 2/ after intramuscular injection in rats, and elucidation of the effects of manganese upon the rates of excretion of nickel, and upon the acute histological reactions produced by Ni/sub 3/S/sub 2/; discovery that the antidotal efficacy of triethylenetetramine (TETA) in acute Ni(II) poisoning in rats is substantially greater than that of other chelating agents, including ..cap alpha..-lipoic acid, diethyldithiocarbamate, d-penicillamine, and glycylglycyl-L-histidine-N-methylamide; observation that the acute renal toxicity of Ni(II) is suppressed by administration of TETA, but that the hyperglycemic and hyperglucagonemic responses to Ni(II) are not prevented by TETA; confirmation that marked erythrocytosis is induced in rats by a single intrarenal injection of Ni/sub 3/S/sub 2/, and elucidation of the time-response and dose-response relationships for the Ni-induced erythrocytosis. (auth)
Date: August 15, 1975
Creator: Sunderman, F. W. Jr.
Partner: UNT Libraries Government Documents Department

Mutagenicity of fractionated test material from the synthetic fuel technology with bacterial systems

Description: The predictive value of short-term genetic tests, such as the Salmonella and Escherichia coli (K-12, 343/113) systems including microsomal activation, is well documented. We have applied the short-term testing to various crude products and effluents from the synthetic fuel technologies. Class fractionation and column chromatography of the test materials and the coupled bioassays can be used to identify the most active fractions (collaborative effort with Analytical Chemistry Division). Reversion at the histidine locus for Salmonella was assayed with each fraction and the results are expressed in units of revertants (strain TA98) per milligram of the starting material (organic content) including metabolic activation with a crude rat liver preparation. Results obtained with the Salmonella system were validated by employing E. coli strains auxotrophic for arginine. Genetic activity is seen with a variety of fractions, largely the basic and neutral (PAH) components. Total activity varies from process to process, thus, the short-term genetic test can be considered a useful prescreen for potential biohazard of various effluents both in plants and in the immediate plant environment.
Date: January 1, 1978
Creator: Rao, T. K.; Young, J. A.; Hardigree, A. A.; Winton, W. & Epler, J. L.
Partner: UNT Libraries Government Documents Department

Electron transfer reactions of excited dyes with metal complexes. Progress report, May 1, 1976--January 31, 1977. [Fe(III)--thionine reaction]

Description: A study was initiated of the factors which determine quantum efficiency of transfer of reducing equivalents between excited dye molecules and metal complexes in their ground state and composition and dynamics of formation and decay of related photostationary states. A ruby laser capable of delivering a 3.6 J, 19 nsec flash was acquired and assembly of an apparatus for laser flash photolysis begun. At the same time, conventional flash photolysis was used to pursue investigation of the dependence upon solvent, anions, pH, and ionic strength of the kinetics of the spontaneous dark reaction of Fe(H/sub 2/O)/sup 3 +//sub 6/ with leucothionine and with semithionine, reactions which contribute to the composition and dynamics of formation and decay of the photostationary state of the iron-thionine photoredox reaction. Results are consistent with formation of an intermediate complex between leucothionine and Fe(III), K/sub A/ = 380 M/sup -1/ and k(elec. transfer) = 0.88 s/sup -1/ at approximately 22/sup 0/ in water solution at pH2, with sulfate as anion and ..mu.. = .05 - .1 M. Under similar conditions in 50 v/v percent aqueous CH/sub 3/CN, K/sub A/ = 780 M/sup -1/, k(elec. transfer) = 0.55 s/sup -1/. In both solvents, sulfate produces a large positive salt effect. Intermediacy of a complex was not established for the faster reaction of Fe(III) with semithionine under similar conditions: K/sub A/ . k(elec. transfer) approximately 3.5 x 10/sup 5/ M/sup -1/s/sup -1/ in H/sub 2/O, approximately 1.0 x 10/sup 4/ in 50 v/v percent aqueous CH/sub 3/CN.
Date: February 1, 1977
Creator: Lichtin, N. N.
Partner: UNT Libraries Government Documents Department