Pressure Perturbation Calorimetry and Guest-Host Chemistry of NDMG and N-MAP with p-Sulfonatocalix[6]arene

The aim of this project is to provide an explanation for recently obtained binding constants for two similar guest molecules, NDMG and N-MAP, with a p-sulfonatocalix[6]arene host in ammonium acetate buffer. This work was done primarily using pressure perturbation calorimetry, which is a technique that determines the coefficient of thermal expansion, α, which is in turn related to the solute molecule's effect on the order of the surrounding water molecules. A series of experiments were designed to test the effects of suspected confounding variables on the validity of PPC data. PPC was then used to study NDMG and N-MAP in ammonium acetate buffer. NDMG exhibited a minimum in α as function of temperature, while N-MAP did not. This difference was theorized to be due to the formation of an intramolecular hydrogen bond in monocationic NDMG that would lower the heat capacity of the molecule and better distribute the molecule's charge. Computational work and nuclear magnetic resonance spectroscopy confirmed that monocationic, ring-closed NDMG has less concentrated charge and more constrained motion than monocationic, ring-open NDMG. This evidence supports the theory that monocationic NDMG forms an intramolecular hydrogen bond and that this may be responsible for the minimum in α. This difference may explain the differences in binding constants between NDMG and N-MAP.

Kinetics of the reaction of alkylamines with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in organic solvents

The following sequence of substitution reactions was studied spectrophotometrically in organic solvents: RNH2 + TCNQ →-HCN 7-substituted TCNQ →-HCN +RNH2 7.7-disubstituted TCNQ where R = butyl, octyl, dodecyl, and hexadecyl. The production of 7-(alkylamino)-7,7,8-tricyanoquinodimethanes proceeds via the formation of the anion radical of TCNQ (TCNQ-·) whose rate of appearance was found to be a function of the chain length of R, reaching a maximum for octylamine. The formation of TCNQ-· was sensitive to the solvent polarity and electron-donor power and was associated with a small enthalpy and a highly negative entropy of activation. Above a certain [C8H17NH2] the rate of disappearance of TCNQ-· was independent of the amine concentration, and the reaction had a much higher enthalpy and entropy of activation. The occurrence of tautomerism precluded an investigation of the conversion of 7-(octylamino)-7,8,8-tricyanoquinodimethane into 7,7-bis(octylamino)-8,8-dicyanoquinodimethane. A study of the reaction of octylamine with 7-morpholino-7,8,8-tricyanoquinodimethane (which does not exist in tautomeric forms) showed that the second substitution step proceeds with the same mechanism as the first one. The only difference between the two compounds (TCNQ and its monosubstituted morpholino derivative) is one of reactivity. © 1985 American Chemical Society.

Studies on Oxidative Couplings in H-Phosphonate Chemistry

In this thesis oxidative coupling of H-phosphonate and H phosphonothioate diesters with different alcohols and amines are presented. Since the reactions with alcohols previously have been particularly unfavourable due to competing side reactions, a modified protocol leading to high coupling yields of structurally diverse hydroxylic components was developed. The phosphorylation reaction was studied using 31P NMR spectroscopy and for the first time the previously only postulated reactive intermediate involved in these reactions was observed. The use of iodine in combination with a bulky chlorosilane in pyridine was found to have a profound effect on both the suppression of side reactions and the rate of the oxidative couplings, and led to a clean formation of phosphorylated products in high yields. This synthetic protocol was then extended to include coupling reactions with bis-functional reagents containing hexamethylene linkers to provide handles for derivatisations of oligonucleotides. A synthetic protocol consisting of the stereospecific oxidative coupling of amines with H-phosphonate diesters to produce phosphoroamidates was designed in such a way that it permitted control of the stereochemical outcome of the reactions. Based on a silylation-mediated reaction utilising phenyl H phosphonothioate monoester as a thiophosphonyl transferring agent, a method was developed and used for the preparation of H-phosphonothioate building blocks for the synthesis of DNA analogues.

Extended donor and acceptor molecules for organic electronics

Die Untersuchung von halbleitenden Materialien auf der Basis von organischen Molekülen stellt ein Gebiet der angewandten Forschung an der Schwelle zur industriellen Nutzung dar. Geringes Gewicht und hohe mechanische Flexibilität ermöglichen völlig neue Produkte, die mit anorganischen Halbleitern nicht zu realisieren sind. Die Herstellung von Bauteilen wie Transistoren, Solarzellen oder Leuchtdioden aus organischen Materialien ist ein komplexes Gebiet, das einer Vielzahl von unterschiedlichen Optimierungen bedarf, um eine konkurrenzfähige Leistung zu erreichen. Die synthetische organische Chemie bietet vielfältige Möglichkeiten, mit maßgeschneiderten Lösungen zum Optimierungsprozess beizutragen. Zum einen können neue aktive Materialien hergestellt werden mit besserer Leistung und leichterer Verarbeitbarkeit. Zum anderen sind Substanzen zugänglich, die z.B. bei der Ladungsträgerinjektion hilfreich sein können.rnIn dieser Arbeit wurde an beiden dieser Fronten gearbeitet. Dabei lag die Entwicklungsstrategie darin, ausgedehnte π-konjugierte Moleküle herzustellen, die entweder besonders elektronenarme Akzeptoren oder elektronenreiche Donoren darstellen. Die genaue Kontrolle der elektronischen Niveaus stellt einen wichtigen Bestandteil dar, um niedrige elektrische Kontaktbarrieren zu Metallen zu erreichen und ausreichend stabile Materialien zu erreichen.rnDer erste Fokus der Arbeiten lag in der Funktionalisierung von Coronen. Dieser PAH stellt einen guten Kompromiss bezüglich seiner Größe dar: Er ist groß genug, um Diffusion in andere Schichten von Bauteilen zu vermeiden, aber nicht zu groß, um Verarbeitung durch Vakuumsublimation zu ermöglichen. Bislang sind praktisch keine Coronen-Derivate in der Literatur beschrieben, weshalb eine neue Synthese entwickelt werden musste, die die Einführung starker Donor- und Akzeptorfunktionalitäten erlaubt. Die photochemische Cyclodehydrierung von substituierten [2.2.2]paracyclophan-trienen stellte sich als hervorragende Möglichkeit heraus, dies zu bewerkstelligen. Es wurde eine Reihe von methoxy-substitutierten Coronenen mit unterschiedlicher Symmetrie hergestellt. Mittels optischer Spektroskopie konnte gezeigt werden, dass Methoxygruppen wenig Einfluss auf die elektronischen Eigenschaften von Coronen haben. Unter Spaltung der Methylether und anschließender Oxidation allerdings sind Coronenketone zugänglich, welche bis zu drei α-Diketongruppen besitzen. Diese Moleküle sind enorm starke Akzeptoren, was durch Cyclovoltammetrie und Vergleich zu anderen Akzeptoren eindrucksvoll gezeigt werden konnte. Die Sublimation dieses Akzeptors auf die Oberfläche von Metallen zeigt einen dramatischen Einfluss auf die Austrittsarbeit dieses Metalls, was zur Herstellung eines ohmschen Kontakts zu organischen Halbleitern von außerordentlichem Nutzen ist. rnDen zweiten Teil der Arbeit bilden Benzodithiophen enthaltende Polymere, die für den Einsatz als aktive Komponente in elektronischen Bauteilen entwickelt wurden. Nach systematischer Strukturoptimierung wurde ein Polymer enthalten, welches in einem Feldeffekt-Transistor auf Standard-Silizium-Substraten Ladungsträger-Mobilitäten über 0,1 cm2/Vs erreicht mit großer Reproduzierbarkeit und ausgezeichneter Transistor-Charakteristik. Es konnte gezeigt werden, dass die durch die Monomergeometrie erzeugte Kurvung des Polymers zu einem optimalen Kompromiss aus Löslichkeit und effektiver Packung darstellt. Auf für industrielle Anwendungen besonders interessanten polymer-basierten Substraten wurde eine noch erheblich bessere Leistung gezeigt. Auf einem PET-Substrat wurden Feldeffekt-Mobilitäten von 0,5 cm2/Vs gemessen mit überzeugenden Reproduzierbarkeit und Stabilität.rnDamit konnte in der Arbeit ein bedeutender Beitrag zur Weiterentwicklung von Materialien für den Einsatz in elektronischen Bauteilen geleistet werden. Die Substanzen versprechen noch erhebliches Potenzial nach intensiver Optimierung und wurden deshalb zum Patent angemeldet.rn

Experimental and Theoretical Study of the OH Vibrational Spectra and Overtone Chemistry of Gas-Phase Vinylacetic Acid

In this study we present the gas-phase vibrational spectrum of vinylacetic acid with a focus on the ν = 1−5 vibrational states of the OH stretching transitions. Cross sections for ν = 1, 2, 4 and 5 of the OH stretching vibrational transitions are derived on the basis of the vapor pressure data obtained for vinylacetic acid. Ab initio calculations are used to assist in the band assignments of the experimental spectra, and to determine the threshold for the decarboxylation of vinylacetic acid. When compared to the theoretical energy barrier to decarboxylation, it is found that the νOH = 4 transition with thermal excitation of low frequency modes or rotational motion and νOH = 5 transitions have sufficient energy for the reaction to proceed following overtone excitation.

Characterization of Halyomorpha halys (brown marmorated stink bug) biogenic volatile organic compound emissions and their role in secondary organic aerosol formation.

The formation of aerosols is a key component in understanding cloud formation in the context of radiative forcings and global climate modeling. Biogenic volatile organic compounds (BVOCs) are a significant source of aerosols, yet there is still much to be learned about their structures, sources, and interactions. The aims of this project were to identify the BVOCs found in the defense chemicals of the brown marmorated stink bug Halymorpha halys and quantify them using gas chromatography-mass spectrometry (GC/MS) and test whether oxidation of these compounds by ozone-promoted aerosol and cloud seed formation. The bugs were tested under two conditions: agitation by asphyxiation and direct glandular exposure. Tridecane, 2(5H)-furanone 5-ethyl, and (E)-2-decenal were identified as the three most abundant compounds. H. halys were also tested in the agitated condition in a smog chamber. It was found that in the presence of 100-180 ppm ozone, secondary aerosols do form. A scanning mobility particle sizer (SMPS) and a cloud condensation nuclei counter (CCNC) were used to characterize the secondary aerosols that formed. This reaction resulted in 0.23 microg/ bug of particulate mass. It was also found that these secondary organic aerosol particles could act as cloud condensation nuclei. At a supersaturation of 1%, we found a kappa value of 0.09. Once regional populations of these stink bugs stabilize and the populations estimates can be made, the additional impacts of their contribution to regional air quality can be calculated.

Organic Wastewater Chemicals in Silver Bow Creek - Butte to Warm Springs Ponds

The purpose of this study is to detail and analyze the distribution, concentration, and loads of 5 organic compounds along Silver Bow Creek in Butte, Montana from the Municipal Wastewater treatment plant to the Warm Springs Ponds. The chemicals analyzed include Carbamazepine (pharmaceutical), Miconazole (fungicide) and three antibiotics – Sulfamethoxazole, Thiabendazole, and Ciprofloxacin. This project begins a 2 year study to analyze 6 additional compounds (11 compounds total), to develop an effective method to detail and analyze OWCs using Mass Spectrometer/Liquid chromatography system, and to aid in assessment of aquatic health and ongoing restoration work. The EPA method 1694 was used for analysis

Effect of Nontronite Smectite Clay on the Chemical Evolution of Several Organic Molecules under Simulated Martian Surface Ultraviolet Radiation Conditions

Most of the phyllosilicates detected at the surface of Mars today are probably remnants of ancient environments that sustained long-term bodies of liquid water at the surface or subsurface and were possibly favorable for the emergence of life. Consequently, phyllosilicates have become the main mineral target in the search for organics on Mars. But are phyllosilicates efficient at preserving organic molecules under current environmental conditions at the surface of Mars? We monitored the qualitative and quantitative evolutions of glycine, urea, and adenine in interaction with the Fe3+-smectite clay nontronite, one of the most abundant phyllosilicates present at the surface of Mars, under simulated martian surface ultraviolet light (190-400 nm), mean temperature (218 +/- 2 K), and pressure (6 +/- 1 mbar) in a laboratory simulation setup. We tested organic-rich samples that were representative of the evaporation of a small, warm pond of liquid water containing a high concentration of organics. For each molecule, we observed how the nontronite influences its quantum efficiency of photodecomposition and the nature of its solid evolution products. The results reveal a pronounced photoprotective effect of nontronite on the evolution of glycine and adenine; their efficiencies of photodecomposition were reduced by a factor of 5 when mixed at a concentration of 2.6x10(-2) mol of molecules per gram of nontronite. Moreover, when the amount of nontronite in the sample of glycine was increased by a factor of 2, the gain of photoprotection was multiplied by a factor of 5. This indicates that the photoprotection provided by the nontronite is not a purely mechanical shielding effect but is also due to stabilizing interactions. No new evolution product was firmly identified, but the results obtained with urea suggest a particular reactivity in the presence of nontronite, leading to an increase of its dissociation rate. Key Words: Martian surface-Organic chemistry-Photochemistry-Astrochemistry-Nontronite-Phyllosilicates. Astrobiology 15, 221-237.

A treatise on chemistry,

I. The non-meallic elements.--II.The metals.--III. The chemistry of the hydrocarbons and their derivatives, or Organic chemistry: pt. I; Pt. II; pt. III; pt. IV 1892; pt. V; pt. VI.

Dictionary of organic compounds; the constitution and physical and chemical properties of the principal carbon compounds and their derivatives, together with the relevant literature references.

Accompanied by "Supplement ... [to vol. 2-3]" (2 v.) Published: New York, Oxford University Press, 1943.

Dictionary of organic compounds; the constitution and physical and chemical properties of the principal carbon compounds and their derivatives, together with the relevant literature references.

Errata slips inserted.

Annual reports on the progress of chemistry.

Mode of access: Internet.

Eighth International congress of applied chemistry, Washington and New York, September 4 to 13, 1912.

"Members": v. 28, p. 365-463.

Seventh International Congress of Applied Chemistry, London, May 27th to June 2d, 1909.

Edited by Sir William Ramsay, William Macnab, and others.

Fownes' manual of chemistry : theoretical and practical.

Includes index.