Physical Chemistry Commons^™

Polarographic Investigation Of Several Tetrakis 1, 3-Diketone Europium Chelates In Acetonitrile, Samuel Lee Jeanjaquet

Chemistry and Chemical Biology ETDs

This study is concerned with the polarographic behavior of several tetrakis 1, 3-diketone chelates of europium and of the 1, 3-diketone ligands in acetonitrile. Such a study should reveal the following: (a) whether the europium (III) in the complexes is reduced directly to the metal, or if reduction to europium (II) takes place followed by reduction to the metal; (b) whether ligands are released during the reduction step(s) and if so, how many; (c) whether the polarographic behavior is such that dissociation constants of the complexes or complex ions can be determined by measuring the shift in half-wave potential as …

Some 2-Aryl-6-Phenylindenes, 2-Aryl-3-Methyl-6-Phenylindenes, 2-Aryl-3, 4-Dihydro-6-Phenylnaphthalenes, And 2-Aryl-3, 4-Dihydro-1-Methyl-6-Phenylnaphthalenes As Liquid Scintillators: The Steric Effects Of A Methyl Group, David Webster Holty

Chemistry and Chemical Biology ETDs

Liquid Solution Scintillator Systems1. Absorption and emission spectra of organic molecules arise from energy transitions within the molecule. Quantization of energy dictates that the energy levels in molecules will be specific and characteristic distances apart. The simplest description of the electronic energy levels in a molecule starts with "ground state" and includes "excited state #1” and so forth; this simple description allows only for the electronic excitation. In practice each electronic energy level is split into sublevels by other energetic transitions in the molecule, such as vibrations and rotations (Figure la).

Liquid Scintillators: Some 3-Aryl-L,2-Dihydronaphthalenes, 3-Aryl-1,2-Dihydro-4-Methylnaphthalenes, 3-Aryl-1,2-Dihydrophenanthrenes And 3-Aryl-1,2-Dihydro-4-Methylphenanthrenes: Steric Effects Of The Methyl Group, Lavinel G. Ionescu

Chemistry and Chemical Biology ETDs

There are two methods commonly employed for the measurement of radiation: the ionization chambers, such as the various types of Geiger­Mliller tubes, and the scintillation counters.

The Synthesis Of Condensed Pyridazines And Related Nitrogen Heterocycles As Potential Anticancer Agents, G. Anne Gerhardt

Chemistry and Chemical Biology ETDs

The antitumor activity found in such ring systems as purine (I), 8 - azapurine (II), pyrazolo[3, 4- d]pyrimidine (Ill) and pteridine (VI) prompted the preparation of substituted benzimidazoles, ν-triazolo­[4, 5-c]- (V), imidazo[4, 5-d]- (IV), pyrazino[2, 3-c]- (VII) and pyrazino[2, 3-d]- (VIII) pyridazines.

Intramolecular Spin-Orbit Coupling In Naphthalene Analogs, Francis Elliott Shoup Iii

Chemistry and Chemical Biology ETDs

The objective of this study was to gain additional insight into the phenomenon of spin-orbit coupling in molecules by examining the intramolecular mechanisms responsible for the phosphorescence of certain types of molecules. Spectrocopic investigations of a series of aromatic hydrocarbons, aromatic heterocyclics, and some of their halogen derivatives are reported. Experimental measurements included absorption spectra, total emission spectra, polarized emission spectra, obtained by the method of photoselection, and radiative lifetimes. It was found that chlorine substitution in naphthalene, quinoline, and quinoxaline has the effect of enhancing the transition probability for radiative transitions from the B_lu component of the ^{3 …}

Crystal Field Splitting In Rare Earth Chelates, Walter George Perkins

Chemistry and Chemical Biology ETDs

Investigations of ligand field effects in the spectra of trisdibenzoyl­methide, trisbenzoylacetonate, and trisacetylacctonatc chelates of trivalent ytterbium and thulium are reported. Chelate absorption and luminescence spectra corresponding to intra-4f electronic transitions exhibit line split­tings similar in magnitude to the crystal field splitting observed in the spectra of inorganic complexes of the rare earth ions.

Absorption spectra of carbon tetrachloride solutions of all the che­lates studied were measured in the visible and near infrared regions. Each ytterbium chelate exhibits an absorption band at 9800A, consisting of three well-resolved peaks. Thulium intra-4f absorption bands appear at 4700A, 6800A, 8000A, 12000A, and 17000A. …

The Radiochemical Purification Of Europium And A Study Of The Nuclear Properties Of Eu157, Eu158 And Eu159, William Richard Daniels

Chemistry and Chemical Biology ETDs

Chemical procedures have been developed for the rapid preparation of radiochemically pure europium sources from rare earth mixtures and from fission products. Unpurified mixtures of the mono- and dirp(l,1,3,3- tetramethylbutyl)phenyl 1 esters of orthophosphoric acid are used to ex­tract rare ei1arths in the (III) oxidation state away from europium in the (II) oxidation state. Europium sources can be prepared in about 30 min-11tes.

A slow􀀼r chemical procedure for the preparation of europium sources which are both radiochemically pure and mass free has also been developed. Di(2-ethylhEtxyl) orthophosphoric acid is used to separate europium from yttrium, which has a high fission …

Potential Diuretic Agents:-The Synthesis Of 4, 7-Disubstituted Derivatives Of 2-Phenylimidazo [4, 5-D]Pyridazine, Miriam P. Malm

Chemistry and Chemical Biology ETDs

"The maintenance of the water balance of an organism is of prime importance for its physiologic well-being." (1) Water, which composes approximately two-thirds of the entire human body weight, is the fluid in which all vital chemical reactions occur. A loss of 25 percent of body water usually proves fatal. The inherent physical and chemical properties of water render it as the ideal fluid to meet the physiological demands of the organism.

Spectroscopic Studies Of Tris (2,2'-Bipyridine)- And Tris (I, 10-Phenanthroline) Iron (Ii), -Ruthenium (Ii), And -Osmium (Ii), Sonia Lee Sabath

Chemistry and Chemical Biology ETDs

The tris(2,2'-bipyridine)- and tris(l,10-phenanthroline) complexes of iron(II), ruthenium(II), and osmium(II) were synthesized, purified, and characterized by analyses. The solution absorption spectra of the compounds were measured both in the ultraviolet and visible regions. The observed ultraviolet absorption bands of the ruthenium and osmium complexes were assigned entirely to transitions, the prominent bands being assigned to ligand (perturbed) transitions by comparison with the published assignments of the corresponding bands in analogous iron complexes. The visible absorption spectra for iron(II) and ruthenium(II) complexes were attributed entirely to singlet-singlet charge transfer transitions. The strong visible absorption bands of osmium(II) complexes were also assigned …

The Synthesis And Evaluation Of Some 2-Arylindenes And 2-Aryl-3h-Benz[E]Indenes As Liquid Scintillation Solutes, James Leslie Schornick

Chemistry and Chemical Biology ETDs

A scintillator, in the chemical sense, is a system which can convert radioactive particle energy to visible and near ultraviolet photon energy. A phenomenon related to scintillation is fluorescence. The difference between scintillation and fluorescence is the source of excitation energy. In the case of scintillation, the exciting energy comes from radioactive particles, while in fluorescence, the exciting energy comes from ultraviolet light.

Energy Migration In Rare Earth Complexes, John Jerome Freeman

Chemistry and Chemical Biology ETDs

Complexes of trivalent samarium, europium, terbium, and dysprosium were prepared for investigations of the luminescence properties of complexed rare earth ions. Rare earth chilates derived from benzoylacetone, dibenzoylmethane, and acetylacetone; rare earth chlorides solvated with water and deuterium oxide; and rare earth oxides dissolved in sodium metaphosphate glasses were synthesized for these studies.

Radiochemical Studies: Isotopic Exchange Reactions, Solvent Effects, Preparation And Properties Of Carrier-Free Amalgams, Hans L. Hamster

Chemistry and Chemical Biology ETDs

The work described in this section is concerned with the kinetics of an S_N2 reaction, the isotopic exchange reaction between iodide ions and p-nitrobenzyl iodide, carried out in an aprotic solvent, acetone, in the presence of various substituted phenols and anisole. This reaction was carried out at concentration of potassium iodide low enough to insure the absence of ion pairs.

An Investigation Of Steric Inhibition Of Resonance In Liquid Scintillators, Richard L. Taber

Chemistry and Chemical Biology ETDs

It is well known that the replacement of two or more of the ortho hydrogen atoms in the benzene rings of biphenyl by lager atoms or groups hinders the rotation about the l.l'-carbon single bond in the biphenyl system. If the groups are so large that they are unable to pass each other upon rotation of the l,l'-bond, then the two benzene rings are forced to assume a non-planar configuration.

Self-Diffusion In Single-Crystal Tungsten And Diffusion Of Rhenium Tracer In Single-Crystal Tungsten, Robert L. Andelin

Chemistry and Chemical Biology ETDs

Self-diffusion in single-crystal tungsten and diffusion of rhenium tracer in single-crystal tungsten have been measured over the temperature range 2660°C to 3230°C by the direct sectioning technique. The initial radioactive layer of tungsten and rhenium tracers was produced on the diffusion samples by bombardment with 9.0-MeV deutrons. It was shown that the initial radioactive layer satisfactorily approximated the boundary-condition requirements of the one-dimensional diffusion equation. The tracers observed in determining the diffusion coefficients were W¹⁸⁵, Re¹⁸³, and Re¹⁸⁴. Diffusion heating of the samples in high vacuum was accomplished by an induction-heating arrangement which included …

The Kinetics Of The Hydrolysis Of Some 2-Imidazolines, Bobby G. Harnsberger

Chemistry and Chemical Biology ETDs

In recent years, 2-imidazolines have become important industrially. Possible applications include uses as drugs, fungicides, emulsifying agents, demulsifying agents, corrosion inhibitors, fuel oil additives and gasoline additives.

The Analysis Of Seed Oils Of Six Tropical Plant Species By Gas Chromatography, Justin C. Hamer

Chemistry and Chemical Biology ETDs

Several factors influenced the choice of tropical plant seeds studied in this research. Among these factors were: (1) an early interest in the chemistry of natural products; (2) the legends surrounding the use of certain plants by native herb "doctors," and (3) the ready availability of the materials at the beginning of this investigation, which was started in Cuba.

A Spectroscopic Study Of Some Rare Earth Complexes, Richard M. Alire

Chemistry and Chemical Biology ETDs

The phenomenon of intramolecular energy transfer was studied using anthranilate, 8-hydroxyquinolate, 2-methyl-8-hydroxyquinolate, and salicylaldehyde rare earth chelates. Line emission characteristic of the rare earth ion was observed whenever the lowest triplet (measured) of the complex was higher in energy than the emitting (resonance) level of the rare earth trivalent ion. The path of energy transfer from the organic portion of the chelate to the rare earth ion was verified as going via the lowest or a nearby triplet state of the complex. Relative quantum yield measurements were made on the anthranilate rare earth series using a photographic method. Gadolinium anthranilate …

High Temperature Vaporization Behavior And Thermodynamic Properties Of Hafnium Diboride, Milton C. Krupka

Chemistry and Chemical Biology ETDs

Vaporization of hafnium diboride has been studied in a tungsten effusion cell over the temperature range 2175°K. to 2500°K. A low-melting eutectic at 2520°K. prevented the use of the effusion cell technique at higher temperatures. An ultra-high vacuum apparatus, capable of producing vacuums of the order of 1 x 10^-12 atm. or better and within which the final series of vapor pressure measurements was made, was designed and constructed during the course of this study. The effect of a high background pressure in producing species more volatile than the ones under investigation was considered to have been reduced to …

The Kinetics Of The Exchange Of Chlorine Atoms Between Hydrogen Chloride And Benzyl Chlorides, Warren Bruce

Chemistry and Chemical Biology ETDs

The study of the rates of chemical reactions in solutions has received a great deal of attention, primarily because of the relative ease with which such investigations can be persued; however, the great number of publications can never obscure the truth that a rigorous treatment of molecular processes in solutions is not available. The approach to the problem has been through extensions of theories which have their origins in descriptions of gaseous systems, and, with few exceptions, these extensions are firmly grounded on the techniques of classical thermodynamics. Hopefully, future advances in the calculation of the partition functions of molecules …

The Synthesis And Medicinal Chemical Study Of Some Pyridazones, Winnifred M. Osner

Chemistry and Chemical Biology ETDs

An examination of the literature revealed that the majority of pyridazines prepared were substituted in the three and six positions. Therefore, it appeared appropriate to prepare four and five substituted pyridazines.

An Investigation Of The Isotopic Exchange Of Arsenic Atoms Between Arsenic(Iii) And Arsenic(V) In Aqueous Hydrochloric Acid Solutions, Lewis L. Anderson

Chemistry and Chemical Biology ETDs

An isotopic exchange reaction is a chemical reaction in which atoms of a given element interchange between two or more chemical forms of the element. A homogeneous stable system is one in which all reactants are in chemical equilibrium and distributed uniformly throughout a single phase. An example of isotopic exchange is the interchange of iodine atoms between iodide ions and ethyl iodide, where the asterisk indicates radioactive atoms of iodine.

Phase Equilibria In Fused Salt Systems: Binary Systems Of Plutonium(Iii) Chloride With The Chlorides Of Magnesium, Calcium Strontium, And Barium, Karl W. R. Johnson

Chemistry and Chemical Biology ETDs

Fused salt systems containing oxides have received the most attention to date, because of their occurrence in minerals and ores and their application to ceramics. The next most widely studied of group of compounds are the metal halides, particularly the metal chlorides. Despite the fact that many of the metal chlorides are hygroscopic, the salts lend themselves to experimentation because a large majority undergo stable solid-liquid transformations below 1000 degrees C, are generally ionic, and are relatively non-corrosive.

Experimental Studies Of The Visible Absorption Spectrum Of Titanium (Iii) Acetylacetonate In Solutions And Rigid Glasses, Arthur L. Langhorst Jr.

Chemistry and Chemical Biology ETDs

Titanium (III) acetylacetonate was synthesized and the visible absorption spectrum was measured. A prominent absorption band, ^ymax at approximately 6000 was found with molar absorption coefficient of ~1000. The spectrum was investigated at temperatures ranging from 25 degrees C to 77 degrees K. At 7 7 degrees K the band was resolved into five well defined peaks at 4750, 5100, 5520, 5950 and 6460. An apparatus for obtaining spectrophotometric measurements of solution and rigid glasses was designed and fabricated.

The Synthesis Of Potential Antitumor Compounds, Duane L. Aldous

Chemistry and Chemical Biology ETDs

The antitumor activity found in such ring systems as the purine, pyrazolo [3,4-d] pyrimidine, and the 8-azapurine prompted the preparation of the imidazo [4,5-d] pyridazine ring system. Castle and Seese were one of the first to study this ring system. 4-Aminoimidazo[4,5-d]pyridazine possessed some anitumor activity. This antitumor activity suggested the preparation of the 4,7-disubstituted-aminoimidazo{4,5-d]pyridazines reported here. The antileukemic activity reported for 6-purinethiol led to the synthesis of several 4- and/or 7-mono-and disubstitutedthioimidazo[4,5-d]pyridazines.

Spectroscopic Studies Of The Luminescences Of Rare Earth Chelates, Ruth Elaine Whan

Chemistry and Chemical Biology ETDs

A variety of lanthanide chelates were prepared for preliminary luminescence studies under excitation by ultraviolet light. From these, chelates of benzoylacetone, dibenzoylmethane, tribenzoylmethane, and 8-hydroxyquinoline were selected for more extensive investigation. Energies of the lowest excited singlet and triplet states of the chelates were determined. Average values of 24,500 cm^-1 and 20,500 cm^-1 respectively were obtained for the dibenzoylmethides and 24,400 cm^-1 and 21,450 cm^-1 for the benzoylacetonates. Only small variations of a few hundred wavenumbers in the positions of the excited states were found as the chelated ion was varied. This investigation in conjunction with …

The Dilute Solution Chemistry Of Antimony, Kent H. Jones

Chemistry and Chemical Biology ETDs

Investigation of the chemistry of the elements by conventional methods is generally limited to concentrations on the order of 10^-5 M or higher. The discovery of radio-activity opened new fields in chemistry among which is the obtaining of information concerning chemical behavior of elements at very low concentrations. For many years after the initial discovery of radioactivity in 1896 by Becquerel, the study of low-concentration chemistry was limited to about ten naturally occurring radioactive elements. A renewed interest in this field was generated after 1934 when it was discovered by Curie and Joliot that radioactive elements could be artificially …

A Study Of The Kinetics Of The Oxidation Of Uranium(Iv) By Cerium(Iv), Floyd Beatty Baker

Chemistry and Chemical Biology ETDs

The kinetics of a number of oxidation-reduction reactions and exchange reactions involving cations of the transition and inner transition elements have been extensively reviewed by T. W. Newton and S. W. Rabideau. These workers represent the formation of the activated complex by an equation which includes only the principal species in solution as reactants.

Spectroscopic Studies Of Metal-Cyanide Complexes: Part 1: Infrared And Visible Absorption Studies Of Cyanide Complexes Of Ni(Ii) In Aqueous Solution, Part 2: An Analysis Of The Infrared Vibrational Spectra Of The Tetracyanonickelate(Ii) Ion In The Solid State, Roy L. Mccullough

Chemistry and Chemical Biology ETDs

In this work, further evidence has been collected establishing the existence of a new ionic species in solutions of sodium tetracyanonickelate(II) and sodium cyanide. Contrary to the literature, however, this work shows that the species is [Ni(CN)₅]^-3 rather than [Ni(CN)₆]^-4.

Liquid Scintillators. Some Aryl Substituted Phenanthrenes And Dihydrophenanthrenes, And Related P-Terphenyls And P-Quaterphenyls, Stephen Paul Birkeland

Chemistry and Chemical Biology ETDs

With the advent of good commercially available photomultiplier tubes, scintillation counters have become increasingly popular for laboratory use. Although there are a number of materials such as ionic crystals, covalent crystals, plastics, and liquid organic solutions, which are used in scintillation counters, liquid organic solutions offer distinct advantages. Because the organic solutes used in liquid scintillation systems have decay times of the order of 10^-8 second, systems with resolving times of the order of 5x10^-10 second may be obtained. This represents an improvement by a factor of 10⁴ over gas counters and 10² over scintillation systems …

A Spectrophotometric Study Of The Analytical Chemistry Of Vanadium, Kenton E. Bentley

Chemistry and Chemical Biology ETDs

Vanadium is most frequently encountered in analytical chemistry in the volumetric determination of vanadium by oxidation-reduction titration. Vanadium is rarely determined gravimetrically and finds little use as a reagent in gravimetric analysis. The simple ionic forms of the valence states of vanadium and the colors of acidic, aqueous solutions of these ions, as reported in the literature, are listed in Table 1. There is some confusion in the nomenclature of the ionic forms; that given in Table 1 is by analogy to chromium.