Current Search: info:fedora/fau:ugr (x) » Department of Chemistry and Biochemistry (x)
View All Items
Pages
- Title
- Manganese-promoted rearrangement of alkynyl carbonyls to allenyl carbonyls with emphasis on asymmetric induction using chiral bases.
- Creator
- Khoram, Anita, Florida Atlantic University, Lepore, Salvatore D., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordinations followed by a based-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. In this work we employed HPLC equipped with a chiral column to determine the enantiomeric excess. Deuterium labeling experiments suggested that the alkyne/allene rearrangement reaction involved an intermediate cumenolate. We also demonstrated that the reaction required a ligand on manganese...
Show moreThe conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordinations followed by a based-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. In this work we employed HPLC equipped with a chiral column to determine the enantiomeric excess. Deuterium labeling experiments suggested that the alkyne/allene rearrangement reaction involved an intermediate cumenolate. We also demonstrated that the reaction required a ligand on manganese for an amine base to be used catalytically. Phosphines were tested as a possible ligand because they are neutral two electron donors that binds to transition metals through their lone pairs. It was observed that the rate of the reaction decreased from 24hr to 3hr by use of phosphine as a ligand. It was also confirmed that amine base with pKa lower then DBU (pKa = 13.6) would not carry out the isomerization. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. Alkoxy base were also used in isomerization that demonstrated enantioselectivity.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fcla/dt/13158
- Subject Headings
- Carbonyl compounds--Synthesis, Organic compounds--Synthesis, Allene, Alkenes, Methathesis (Chemistry), Isomerism
- Format
- Document (PDF)
- Title
- Diterpene biosynthesis in early ontogenetic stages of Pseudopterogorgia elisabethae and Pseudopterogorgia bipinnata.
- Creator
- Mukherjee, Maia Stapleton, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
There is growing evidence that secondary metabolites isolated from some marine invertebrates may actually be produced by a symbiont. The capacity of early ontogenetic stages of Pseudopterogorgia elisabethae and Pseudopterogorgia bipinnata to biosynthesize biologically active and pharmaceutically important diterpenes was examined. These early life stages lack the algal symbionts found in adult colonies of the species, thus removing one level of complexity. The larvae and polyps of these two...
Show moreThere is growing evidence that secondary metabolites isolated from some marine invertebrates may actually be produced by a symbiont. The capacity of early ontogenetic stages of Pseudopterogorgia elisabethae and Pseudopterogorgia bipinnata to biosynthesize biologically active and pharmaceutically important diterpenes was examined. These early life stages lack the algal symbionts found in adult colonies of the species, thus removing one level of complexity. The larvae and polyps of these two species produced high concentrations of the diterpenoid secondary metabolites, one of which proved to significantly deter fish-feeding in in situ feeding assays. Additionally, a novel cembrenoid diterpene was isolated from P. bipinnata. The structure of this compound, bipinnatolide L (40) was solved using 1D and 2D NMR experiments.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13297
- Subject Headings
- Chemistry, Biochemistry
- Format
- Document (PDF)
- Title
- POLARIZED CRYSTAL SPECTRA OF QUADRATE CHROMIUM(III) COMPLEXES.
- Creator
- KLEIN, ROBERT LEWIS, JR., Florida Atlantic University, Perumareddi, Jayarama R., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The polarized crystal spectra of a series of tetragonal trans- diacidobis (ethylenediamine) chromium (III) complexes, trans-[Cr(en)2XY], where X= Y = Br-, H2O, F-, Cl- and X= H2O, Y = OH-, F-, have been measured at liquid nitrogen temperature, achieving better resolution of the split components of the cubic spin-allowed bands, and also definite energy level assignments. The observed band positions have been fitted with the predicted transition energies by the use of the appropriate energy...
Show moreThe polarized crystal spectra of a series of tetragonal trans- diacidobis (ethylenediamine) chromium (III) complexes, trans-[Cr(en)2XY], where X= Y = Br-, H2O, F-, Cl- and X= H2O, Y = OH-, F-, have been measured at liquid nitrogen temperature, achieving better resolution of the split components of the cubic spin-allowed bands, and also definite energy level assignments. The observed band positions have been fitted with the predicted transition energies by the use of the appropriate energy equations for d^3 configuration immersed in tetragonal fields with full configuration interaction. The ligand field parameters, which include the cubic and axial, and the electron correlation parameter B have been evaluated by such a fitting. The derived parameters have been analyzed and their significance discussed. Using thick crystals, we have uncovered a rich doublet structure in some of the complexes and tentative values of the electron correlation parameter C have been obtained for all the complexes.
Show less - Date Issued
- 1971
- PURL
- http://purl.flvc.org/fcla/dt/13454
- Subject Headings
- Chromium
- Format
- Document (PDF)
- Title
- ATOMIC MOLECULAR THEORY: A PROGRAMMED TEXT USED IN THE TEACHING OF BASIC ATOMIC AND MOLECULAR ORBITAL THEORY IN A HIGH SCHOOL PROGRAM OF CHEMISTRY.
- Creator
- SEVERANCE, H. WILSON, JR., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
This program was developed from necessity found in the teaching of molecular geometry to high school chemistry classes. Recent journals and textbooks were consulted in evaluation of the modern emphasis on instruction in molecular geometry at the high school level, and the topic was then developed fully for use in the chemistry course at the Ransom School, serving as a base for other instructional units. A self-teaching concept was employed in this manual in order that the student might...
Show moreThis program was developed from necessity found in the teaching of molecular geometry to high school chemistry classes. Recent journals and textbooks were consulted in evaluation of the modern emphasis on instruction in molecular geometry at the high school level, and the topic was then developed fully for use in the chemistry course at the Ransom School, serving as a base for other instructional units. A self-teaching concept was employed in this manual in order that the student might proceed at his own pace and according to his own needs. The principal intention was to familiarize the student with the shapes and configurations of various molecules and thereby to give him greater insight into the physical picture of molecular interaction in chemical reaction.
Show less - Date Issued
- 1974
- PURL
- http://purl.flvc.org/fcla/dt/13656
- Subject Headings
- Molecular orbitals--Study and teaching (Secondary), Chemistry--Study and teaching (Secondary)--Programmed instruction, Atomic theory--Study and teaching (Secondary)
- Format
- Document (PDF)
- Title
- A SELF-RELIANT APPROACH TO CHEMICAL INSTRUMENTATION.
- Creator
- N'GURUMO, N'DETENGA., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
This thesis was planned to aid teachers in introducing chemical instrumentation in upper secondary or undergraduate chemistry courses. The problems encountered and solved in the construction of a single beam visible range spectrophotometer, conductance bridge, and polarimeter are described. Experiments were carried out with each instrument to demonstrate their efficiency as compared to commercial models. Pertinent theory on the operation of the instruments is included that can be easily...
Show moreThis thesis was planned to aid teachers in introducing chemical instrumentation in upper secondary or undergraduate chemistry courses. The problems encountered and solved in the construction of a single beam visible range spectrophotometer, conductance bridge, and polarimeter are described. Experiments were carried out with each instrument to demonstrate their efficiency as compared to commercial models. Pertinent theory on the operation of the instruments is included that can be easily understood by students on this educational level. Construction of the instruments is simple and inexpensive, which allows schools with limited budgets to introduce topics on instrumentation into the chemistry curriculum.
Show less - Date Issued
- 1974
- PURL
- http://purl.flvc.org/fcla/dt/13690
- Subject Headings
- Chemistry--Study and teaching (Secondary)
- Format
- Document (PDF)
- Title
- ELECTROCHEMICALLY CATALYZED REDUCTION OF ACETYLENE BY A MOLYBDENUM - CYSTEINE COMPLEX.
- Creator
- LEDWITH, DEBRA ANN, Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The binuclear , di-mju-oxo-bridged molybdenum(V)-cysteine complex, Na2Mo2O4(cys)2, is frequently cited as a chemical model for nitrogenase enzyme. Coulometric reduction of Na2Mo2O4(cys)2 at the potential of Mo(V)--> Mo(III) reduction (-1. 35 to -1.50 V vs. SCE) in the presence o£ the nitrogenase substrate, acetylene, produces ethylene and ethane. Reduction of C2H2 does not occur in the absence of the molybdenumcysteine complex. The quantities of C2H4 and C2H6 produced are greater than the...
Show moreThe binuclear , di-mju-oxo-bridged molybdenum(V)-cysteine complex, Na2Mo2O4(cys)2, is frequently cited as a chemical model for nitrogenase enzyme. Coulometric reduction of Na2Mo2O4(cys)2 at the potential of Mo(V)--> Mo(III) reduction (-1. 35 to -1.50 V vs. SCE) in the presence o£ the nitrogenase substrate, acetylene, produces ethylene and ethane. Reduction of C2H2 does not occur in the absence of the molybdenumcysteine complex. The quantities of C2H4 and C2H6 produced are greater than the stoichiometric molybdenum content, hence the reduction is catalytic. Acetylene reduction is accompanied by catalytic hydrogen evolution at the surface of the mercury electrode. The rate of acetylene reduction and product yields vary with pH, applied electrode potential, concentration of Na2Mo2O4(cys)2, and the buffer salt. A mechanism for the catalytic process is proposed, and its relationship to chemical models for nitrogenase enzyme is discussed.
Show less - Date Issued
- 1975
- PURL
- http://purl.flvc.org/fcla/dt/13732
- Subject Headings
- Acetylene reduction assay, Molybdenum
- Format
- Document (PDF)
- Title
- ELECTROCATALYTIC REDUCTION OF ACETYLENE BY MOLYBDENUM-CYSTEINE AND MOLYBDENUM-EDTA COMPLEXES.
- Creator
- LEAZENBEE, LOUIS O., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Binuclear oxo- and sulfide-bridged Mo(V)-cysteine and Mo(V)-EDTA complexes are chosen as model compounds for nitrogenase enzyme. Both groups of complexes undergo electrochemical reduction in a single four- electron step to Mo(III) dimers. The reduced binuclear Mo (III) units dissociate into catalytically active species capable of reducing the nitrogenase substrate, acetylene. Ease of dissociation increases as oxygen is replaced by sulfur in the bridging unit. Electrocatalytic reduction...
Show moreBinuclear oxo- and sulfide-bridged Mo(V)-cysteine and Mo(V)-EDTA complexes are chosen as model compounds for nitrogenase enzyme. Both groups of complexes undergo electrochemical reduction in a single four- electron step to Mo(III) dimers. The reduced binuclear Mo (III) units dissociate into catalytically active species capable of reducing the nitrogenase substrate, acetylene. Ease of dissociation increases as oxygen is replaced by sulfur in the bridging unit. Electrocatalytic reduction products of acetylene consist primarily of C2H4 and C2H6 at low partial pressures, but C4H6, C4H8, and higher hydrocarbons predominate at higher pressures. The reduction of substrate is believed to occur by a Mo(III) catalyst adsorbed on the electrode surface. A mechanism is proposed for the e lectrocatalysis, and its relationship to the enzymic catalysis is discussed.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13880
- Subject Headings
- Electrochemical analysis, Enzymatic analysis
- Format
- Document (PDF)
- Title
- REACTIONS OF LINEAR ALKYLDIMETHYLAMINE OXIDES WITH IODINE IN WATER, DICHLOROMETHANE AND HEPTANE.
- Creator
- HUDSON, ALICE PETERSON, Florida Atlantic University, Perumareddi, Jayarama R., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The complexes of iodine with linear alkyl (C1, C8, C10 , C12 , C14 and C16) dimethylamine oxides have been studied in the solvents heptane, dichloromethane, and water. In the solvents heptane and dichloromethane and in aqueous surfactant micelles, alkyldimethylamine oxides react with iodine to form donor-acceptor complexes. Trimethylamine oxide is not soluble in heptane and does not form micelles in water so no complexes were fanned in these systems. In heptane and in dichloromethane the...
Show moreThe complexes of iodine with linear alkyl (C1, C8, C10 , C12 , C14 and C16) dimethylamine oxides have been studied in the solvents heptane, dichloromethane, and water. In the solvents heptane and dichloromethane and in aqueous surfactant micelles, alkyldimethylamine oxides react with iodine to form donor-acceptor complexes. Trimethylamine oxide is not soluble in heptane and does not form micelles in water so no complexes were fanned in these systems. In heptane and in dichloromethane the molecular complex ionizes to an "inner" complex in the presence of unassociated amine oxide. The effect of the surface activity is to reduce the concentration of free amine oxide and suppress this ionization. In the case of trimethylamine oxide in dichloromethane forming the dihydrate suppresses inner complex formation. In aqueous micelles the inner complex hydrolyzes to the protonated amine oxide, iodide ion, and hypoiodous acid which appears to oxidize water to molecular oxygen in the presence of the amine oxide micelles. Excess iodine complexes with iodide ion yielding triiodide ion which forms an undissociated ion pair with the micellar protonated amine oxide.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13886
- Subject Headings
- Alkylation
- Format
- Document (PDF)
- Title
- ELECTROCHEMISTRY OF MONOMERIC MOLYBDENUM (VI)-, (V)-, (IV)- AND (III)- CATECHOL COMPLEXES IN AQUEOUS MEDIA.
- Creator
- CHARNEY, LYNN MARLENE., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The electrochemical reduction of the cis-dioxo Mo(VI)-catechol complex, MoO2(cat2^2-, is investigated at a mercury electrode in pH 3.5-10 aqueous buffers utilizing the techniques of cyclic voltammetry and controlled potential coulometry. The reduction of MoO2(cat2^2- proceeds by successive two-proton, one-electron and two- proton, two-electron transfer steps which produce monomeric Mo(V) and Mo(III) species. At pH 3.5-7 the Mo(V) monomer is unstable and undergoes dimerization. The mechanism...
Show moreThe electrochemical reduction of the cis-dioxo Mo(VI)-catechol complex, MoO2(cat2^2-, is investigated at a mercury electrode in pH 3.5-10 aqueous buffers utilizing the techniques of cyclic voltammetry and controlled potential coulometry. The reduction of MoO2(cat2^2- proceeds by successive two-proton, one-electron and two- proton, two-electron transfer steps which produce monomeric Mo(V) and Mo(III) species. At pH 3.5-7 the Mo(V) monomer is unstable and undergoes dimerization. The mechanism of the dimerization reaction and the structure of the Mo(V) dimer produced are determined. At pH 7-10 the monomeric Mo (V) and 2- Mo(III) complexes produced by reduction of MoO2(cat2^2- are stable. A stable Mo(IV) species is obtained upon reoxidation of the Mo( III ) monomer. The epr spectrum of the monomeric Mo(V) complex and visible spectra of all oxidation states in alkaline solution arc reported.
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/13979
- Subject Headings
- Electrochemistry
- Format
- Document (PDF)
- Title
- CREATINE PHOSPHOKINASE ISOENZYME ANALYSIS BY SELECTIVE ACTIVATION WITH THIOLS AND INHIBITION BY ANTIBODIES. AN EVALUATION AND ADAPTATION TO AUTOMATED ANALYSIS.
- Creator
- BERNARD, DONALD JAMES., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Analysis of creatine phosphokinase (CPK) isoenzymes is the best clinical test for diagnosis of heart disease. Two new methods for quantitative analysis of these enzymes are selective activation with thiols and specific inhibition by antibodies. These new methods and the conventionally used technique of electrophoresis are comparatively evaluated using assayed controls and cardiac patient serum samples. Results indicate that thiol activation and antibody inhibition are preferred methods for...
Show moreAnalysis of creatine phosphokinase (CPK) isoenzymes is the best clinical test for diagnosis of heart disease. Two new methods for quantitative analysis of these enzymes are selective activation with thiols and specific inhibition by antibodies. These new methods and the conventionally used technique of electrophoresis are comparatively evaluated using assayed controls and cardiac patient serum samples. Results indicate that thiol activation and antibody inhibition are preferred methods for CPK cardiac isoenzyme analysis because they have lower levels of detection, fewer false negative results, and are considerably more efficient than electrophoresis. The new techniques also are adapted to automated spectrophotometric instrumentation, which further contributes to their accuracy and procedural efficiency. Thus, thiol activation and antibody inhibition methods should provide more sensitive and reliable CPK isoenzyme analysis for critical supportive evidence in heart disease diagnosis and treatment
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/13982
- Subject Headings
- Chemistry, Analytic
- Format
- Document (PDF)
- Title
- THE FORMATION OF DIHALOACETONITRILES BY CHLORINATION OF NATURAL WATER.
- Creator
- TREHY, MICHAEL LEE., Florida Atlantic University, Bieber, Theodore I., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Dihaloacetonitriles (DHANs) are shown to be produced by the chlorination of natural water, thus joining the ranks of the trihalomethanes (THMs) likewise produced by chlorination. Certain amino acids such as aspartic acid, tryptophan, and tyrosine are implicated as precursor substances for the DHANs and also to some extent for the THMs. The degradation of DHANs by hydrolysis and by thiosulfate was studied. Various methods of analysis are evaluated with respect to their ability to determine...
Show moreDihaloacetonitriles (DHANs) are shown to be produced by the chlorination of natural water, thus joining the ranks of the trihalomethanes (THMs) likewise produced by chlorination. Certain amino acids such as aspartic acid, tryptophan, and tyrosine are implicated as precursor substances for the DHANs and also to some extent for the THMs. The degradation of DHANs by hydrolysis and by thiosulfate was studied. Various methods of analysis are evaluated with respect to their ability to determine DHANs and THMs. The dilemma faced by water plants in dealing with the dual problem of DHANs and THMs is discussed. The role of hydrolysis in the formation of THMs has also been evaluated.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14011
- Subject Headings
- Water--Purification--Chlorination
- Format
- Document (PDF)
- Title
- ELECTROCATALYTIC REACTIONS OF OXO ANIONS WITH MOLYBDENUM - CATECHOL COMPLEXES.
- Creator
- LAHR, SUZANNE KAY, Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Catalytic reductions of NO2, ClO3, and BrO3 by aqueous molybdenum-catechol complexes at pH 9 are investigated by electrochemical techniques. Binding of substrate to the molybdenum center occurs through the unshared electron pair of the substrate central atom. The molybdenum (V) and - (IV) oxidation states are catalytically active, while Mo(III) is not. A single mechanism for the reaction of Mo(V) with all three substrates is proposed, and a rate expression for this reaction is derived....
Show moreCatalytic reductions of NO2, ClO3, and BrO3 by aqueous molybdenum-catechol complexes at pH 9 are investigated by electrochemical techniques. Binding of substrate to the molybdenum center occurs through the unshared electron pair of the substrate central atom. The molybdenum (V) and - (IV) oxidation states are catalytically active, while Mo(III) is not. A single mechanism for the reaction of Mo(V) with all three substrates is proposed, and a rate expression for this reaction is derived. General features of the Mo (IV) reaction are describec. Nitrous oxide was identified by gas chromatography as a product of the Mo(V) - NO2 reaction.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14118
- Subject Headings
- Molybdenum--Analysis, Catechol--Analysis
- Format
- Document (PDF)
- Title
- The electronic structures of dimolybdenum compounds; detailed electronic absorption and electrochemical studies of dimolybdenum BAII complexes.
- Creator
- Shih, Keng-Yu., Florida Atlantic University, Baird, Donald M., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The complexes Mo2(OAc)3(BAII), where BAII is 1,3-bis(arylimino)isoindoline, have been synthesized. A detailed interpretation of their 1H-NMR spectra has been made. The structure of the bis(pyridylimino)isoindoline derivative has been determined by X-ray analysis to facilitate the assignment of the resonance lines in the spectra. It has been found that there are trends in energies and intensities of the delta-->delta* transition in these compounds. Electron withdrawing substituents on the...
Show moreThe complexes Mo2(OAc)3(BAII), where BAII is 1,3-bis(arylimino)isoindoline, have been synthesized. A detailed interpretation of their 1H-NMR spectra has been made. The structure of the bis(pyridylimino)isoindoline derivative has been determined by X-ray analysis to facilitate the assignment of the resonance lines in the spectra. It has been found that there are trends in energies and intensities of the delta-->delta* transition in these compounds. Electron withdrawing substituents on the aromatic nitrogen heterocycles in BAII shift the delta-->delta* transition to a lower energy and a higher intensity as compared to electron releasing substituents. These trends suggest that mixing of M-->L charge transfer transitions with the delta-->delta* transitions is occurring in these compounds which is consistent with the results of electrochemical trends in oxidation potentials. The complexes which are hardest to oxidize in general have the lowest delta-->delta* transition.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14516
- Subject Headings
- Chemistry, Inorganic
- Format
- Document (PDF)
- Title
- Nuclear magnetic resonance spectroscopic studies of metallocene (IVB) squarate polymers and other metallocene (IVB)-containing polymers.
- Creator
- Li, Alicia Qing, Florida Atlantic University, Carraher, Charles E., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Group IVB metallocene polymers and oligomers undergo a pi-sigma rearrangement of the cyclopentadienyl moieties in DMSO based on NMR data. The sigma-Cp rings are stereochemically rigid at room temperature.
- Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14681
- Subject Headings
- Organometallic polymers, Metallocenes, Nuclear magnetic resonance
- Format
- Document (PDF)
- Title
- Comparison of alkyl-bonded alumina-based stationary phases for peptide separation by high performance liquid chromatography.
- Creator
- Ramdial, Nirmala Debra-Ann, Florida Atlantic University, Haky, Jerome E., Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
- Abstract/Description
-
The performance of several alkyl-bonded alumina-based stationary phases was evaluated by comparing the separation of synthetic octapeptide and polypeptide mixtures and tryptic digests of larger proteins. These phases were of differing pore diameter, alkyl chain length modification and particle shape and size. The separations were compared to standard silica phases. The narrow pore octadecyl bonded alumina phase outperformed the other alumina and silica phases in terms of separation efficiency...
Show moreThe performance of several alkyl-bonded alumina-based stationary phases was evaluated by comparing the separation of synthetic octapeptide and polypeptide mixtures and tryptic digests of larger proteins. These phases were of differing pore diameter, alkyl chain length modification and particle shape and size. The separations were compared to standard silica phases. The narrow pore octadecyl bonded alumina phase outperformed the other alumina and silica phases in terms of separation efficiency and mobile phase resistance. Superior performance is attributed to the enhanced solute mass transfer properties and the unique morphology of the microplatelet alumina particles. The mechanism of separation gradually changes with increasing size of the peptide.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14831
- Subject Headings
- Peptides--Separation, Liquid chromatography
- Format
- Document (PDF)
- Title
- Synthesis and characterization of polyazo-group IVB metallocene dichloride derivatives.
- Creator
- Kloss, John Edward, Florida Atlantic University, Carraher, Charles E., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Reaction of Group IVB metallocene dichlorides with a monoaza dye yields a polymer in which the metal is bonded to a sulfonic and a hydroxyl group. The structure and bonding of the polymer was confirmed using infrared, mass spectrometry and 1H-NMR spectroscopy. Thermo and elemental analysis was used to confirm the presence of the metal. The stability of the polydye to the monomer unit was compared employing an argon laser in the visible region.
- Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14912
- Subject Headings
- Metallocenes, Organometallic polymers, Infrared spectroscopy, Azo compounds
- Format
- Document (PDF)
- Title
- Photodegradation of bromacil and terbacil by ultraviolet radiation.
- Creator
- Johnson, Hannah Kalyani, Florida Atlantic University, Parkanyi, Cyril, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The photodegradation of bromacil (5-bromo-3-sec-butyl-6-methyluracil) and terbacil (5-chloro-3-tert-butyl-6-methyluracil) by ultraviolet radiation has been investigated. Irradiation of aerated aqueous solutions of the title compounds (25 ppm), led to fast degradation of both. The reactions were found to follow first order kinetics with rate constants 5.77x10^-1 hr^-1 in the case of bromacil and 8.45x10^-2 hr^-1 in the case of terbacil. Degradation in ethanol and cyclohexane was also studied,...
Show moreThe photodegradation of bromacil (5-bromo-3-sec-butyl-6-methyluracil) and terbacil (5-chloro-3-tert-butyl-6-methyluracil) by ultraviolet radiation has been investigated. Irradiation of aerated aqueous solutions of the title compounds (25 ppm), led to fast degradation of both. The reactions were found to follow first order kinetics with rate constants 5.77x10^-1 hr^-1 in the case of bromacil and 8.45x10^-2 hr^-1 in the case of terbacil. Degradation in ethanol and cyclohexane was also studied, but the solutions were not analyzed for photoproducts. The photoreaction mixture of both the herbicides in water showed four peaks on GC, indicating four photoproducts. Loss of halogens from the heterocyclic ring has been observed as shown by the presence of Br- in the case of bromacil and Cl- in the case of terbacil in the photoreaction solution. 6-Methyluracil which was isolated from the aqueous fraction of the photoreaction mixture was the common photoproduct from both bromacil and terbacil. From the organic fractions 3-sec-butyl-5-acetyl-5-hydroxyhydantoin was identified in the case of bromacil and 3-tert-butyl-5-acetyl-5-hydroxyhydantoin in the case of terbacil. The other two photoproducts were left unidentified.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14929
- Subject Headings
- Ultraviolet radiation, Photochemistry--Deterioration, Herbicides, Uracil
- Format
- Document (PDF)
- Title
- Spectroscopic and computational studies of the sol-to-gel process.
- Creator
- Kolega, Renato, Florida Atlantic University, Jackson, Mark, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Structural determination of tetramethoxysilane-derived sol-gel solutions was undertaken with ATR FT-IR. The ATR sampling method provided in-situ and almost real-time analysis. This experimental technique permitted the continuous examination of the sol-gel process throughout its initial stages. The conversion of the starting material, the formation of methanol, and the development of various functional groups were observed. Based on model silica sol-gel compounds, the AM1 quantum mechanical...
Show moreStructural determination of tetramethoxysilane-derived sol-gel solutions was undertaken with ATR FT-IR. The ATR sampling method provided in-situ and almost real-time analysis. This experimental technique permitted the continuous examination of the sol-gel process throughout its initial stages. The conversion of the starting material, the formation of methanol, and the development of various functional groups were observed. Based on model silica sol-gel compounds, the AM1 quantum mechanical computational method was applied in order to determine the favored condensation products. Cyclic oligomers are preferred over chains for larger condensation products. Theoretical vibrational frequencies were obtained for these model compounds as well. Correlation of the computational results with experimental compounds were made.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14948
- Subject Headings
- Ceramic materials, Colloids
- Format
- Document (PDF)
- Title
- The synthesis of bis(dimolybdenum)-1,3,5,7-tetrakis(2-pyridylimino) benzodipyrrole as a precursor for an inorganic, quadruple bond containing polymer.
- Creator
- Kavanaugh, David John, Florida Atlantic University, Baird, Donald M., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The planar, dinuclear, tridentate ligands, 1,3,5,7-tetrakis(2-pyridylimino)benzodipyrrole (TAII) and 1,3,5,7-tetrakis(4,6-dimethyl-2-pyridylimino)benzodipyrrole (DiMeTAII) were synthesized and characterized as were all intermediates characterized by both infrared and 1H-NMR spectra. Evidence is presented for the formation of Mo4(OAc)6-(DiMeTAII) (I), the dinuclear analog of Mo2(OAc)3-BAII using UV/Vis to show the delta--->delta* transition typical of the quadruple bond and for the...
Show moreThe planar, dinuclear, tridentate ligands, 1,3,5,7-tetrakis(2-pyridylimino)benzodipyrrole (TAII) and 1,3,5,7-tetrakis(4,6-dimethyl-2-pyridylimino)benzodipyrrole (DiMeTAII) were synthesized and characterized as were all intermediates characterized by both infrared and 1H-NMR spectra. Evidence is presented for the formation of Mo4(OAc)6-(DiMeTAII) (I), the dinuclear analog of Mo2(OAc)3-BAII using UV/Vis to show the delta--->delta* transition typical of the quadruple bond and for the determination of percent molybdenum which is consistent with the proposed structure. A review of recent studies into the field of quadruply bonded metal containing polymers will be discussed along with application of compound (I) in this field.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14950
- Subject Headings
- Ligands (Biochemistry), Metal-metal bonds, Diffusion bonding (Metals)
- Format
- Document (PDF)
- Title
- High performance liquid chromatographic separation of sedimentary vanadyl porphyrins.
- Creator
- Huang, Xiaoxue, Florida Atlantic University, Baker, Earl W., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
A method of reversed phase HPLC gradient elution was developed and evaluated for the separation of vanadyl porphyrins. Separation was compared with the result of isocratic elution. It shows that gradient elution method is suitable for vanadyl porphyrin separation and better separation result can be obtained by gradient elution. Gradient elution improves the separation by changing the retention time of different components in the sample mixture and increases the difference of k' (capacity...
Show moreA method of reversed phase HPLC gradient elution was developed and evaluated for the separation of vanadyl porphyrins. Separation was compared with the result of isocratic elution. It shows that gradient elution method is suitable for vanadyl porphyrin separation and better separation result can be obtained by gradient elution. Gradient elution improves the separation by changing the retention time of different components in the sample mixture and increases the difference of k' (capacity factor). Vanadyl porphyrin samples Bakken 6362', Treibs #1 and Treibs #3 were analyzed by this method. Results correlate very well with the results of mass spectrometry analysis of these samples which have been done by some other workers.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/15094
- Subject Headings
- Porphyrins, High performance liquid chromatography
- Format
- Document (PDF)