<p>This thesis deals with the synthesis and characterization ofnovel polyhydroxyl surfactants. The first part describes thesynthesis of a number of stereoisomers of a polyhydroxylsurfactant, and the second part concerns surface chemicalcharacterization.</p><p>A stereodivergent route for preparation of the hydrophilichead group was developed, featuring consecutive stereoselectivedihydroxylations of a diene. This afforded in total fourdifferent polyhydroxyl head groups. These surfactant headgroups were natural and unnatural sugar analogues, and wereused for the coupling with two different hydrophobic tailgroups.</p><p>Three of these surfactants were used to investigate thechiral discrimination in Langmuir monolayers at an air-waterinterface. The isotherms showed a remarkable difference incompressibility between surfactants of diastereomericrelationship and also a pronounced chiral discriminationbetween racemic and enantiomerically pure surfactants favoringheterochiral discrimination.</p>

Herein are presented collective studies of amino acid-based surfactants, also known as lipoamino acids, at liquid interfaces. Chapter III describes an investigation of domain morphology of N-Stearoylglutamic acid (N-SGA) Langmuir monolayers at the air/water interface by epifluorescence microscopy. Anisotropic feather-like domains were observed in L-enantiomeric monolayers while symmetric circular domains were found in racemic N-SGA monolayers. At a surface pressure of 30 mN/m the enantiomeric domains melted at 31 ??C while the racemic domains melted at 27 ??C. This result is exactly opposite to the behavior found in bulk crystals where the racemate melts at a higher temperature. These results were explained in terms of different molecular packing and hydrogen bonding between bulk crystals and two-dimensional thin films for enantiomeric and racemic compounds. Chapter IV summarizes the investigations of hydrogen bonding in N-acyl amino acid monolayers by vibrational sum-frequency spectroscopy (VSFS). The intermolecular hydrogen bonding interaction between the adjacent molecules through amide-amide groups in N-stearoylalanine (N-SA) is characterized by an NH stretch peak at 3311 cm-1. This is the first time that the amide NH stretching signals have been detected with the VSFS technique. A similar peak was detected at 3341 cm-1on N-SGA monolayer. The higher frequency indicates that the H-bond strength is weaker due to the larger size of the glutamic acid residue. The NH stretch mode can thus be used as a fingerprint of hydrogen bonding among amide-amide groups. A peak at 3050 cm-1 due to hydrogen bonding among carboxyl groups was also resolved from the VSFS spectra. Molecular models of intermolecular hydrogen bonding were proposed.

I den här avhandlingen har vi studerat hur man kan göra nya tensider. En tensid är en speciell molekyl som har förmågan att lösa sig i både vatten och olja. Man kan göra följande experiment hemma: Fyll en glasburk till hälften med vatten och tillsätt en droppe matolja. Oljan bildar en droppe ovanpå vattnet, därför att vatten och olja inte är blandbara. Vatten är polärt och olja är opolärt. Om man rör om med en sked kommer oljedroppen förvisso att dela upp sig i mindre droppar, men så snart man slutar att röra kommer dessa att lägga sig på vattenytan igen. Sätt nu en droppe diskmedel till blandningen och rör om. Nu sprider sig oljedropparna mycket bättre i vattnet, och de lägger sig heller inte på vattenytan lika fort när man slutar att röra. Det här beror på att diskmedel innehåller en tensid, som har en polär och en opolär del. Den polära delen passar ihop med det polära vattnet, medan den opolära delen passar ihop med den opolära oljan. På så vis kan tensiden hjälpa till att lösa upp opolära ämnen i polära vätskor. Den aktiva delen av ett läkemedel består ofta av opolära ämnen, vilka inte löser sig i polära vätskor såsom vatten. Eftersom kroppen består till stor del av vatten måste man ändå försöka få läkemedlet vattenlösligt, för att möjliggöra transport via blodet till problemområdet. Det kan man uppnå genom att tillsätta tensider. Om läkemedel-tensidblandningen ska ges till djur eller människor får inte tensiden orsaka någon skada i kroppen. Vi har försökt framställa tensider som ska kunna användas för att just lösa läkemedel i vatten. För att kunna framställa nya tensider måste man ha kunskap i organisk syntes. Det betyder att man måste veta hur man från små intermediat (”byggstenar”) successivt kan bygga upp nya molekyler som har de önskvärda egenskaperna. Genom olika typer av organisk syntes har vi byggt upp tre nya tensidtyper, vars egenskaper vi studerat med olika mätningar. Ingen av dessa tensider lämpade sig som tillsats till läkemedel, men vårt arbete har givit mycket ny kunskap om hur framtida tensidmolkyler kan tillverkas och vilka egenskaper de får. / This thesis deals with the synthesis and characterization of new polyhydroxy surfactants. The first part describes the synthesis of three new surfactant classes, and the second part concerns the surface chemical characterization of the synthesized surfactants. A stereodivergent route for preparation of hydrophilic head groups was developed, that featured consecutive stereoselective dihydroxylations of a diene. This method provided in total four different polyhydroxylated head groups. These surfactant head groups were natural and unnatural sugar analogues, and were used for the coupling with two different hydrophobic tail groups. Another approach took advantage of a metathesis reaction and provided a polyhydroxylated compound that was coupled to 12-hydroxy stearic acid The third class of surfactants contained an amide linkage between the hydrophilic and the hydrophobic parts. The hydrophilic part consisted of two glucose units, and 12-hydroxy stearic acid was used as the hydrophobic part. The hydroxy moiety in the tail group was further functionalized as aliphatic esters, which provided in total four different surfactants. A selection of the surfactants was used to investigate the chiral discrimination in Langmuir monolayers at an air-water interface. The isotherms showed a remarkable difference in compressibility between diastereomeric surfactants and also a pronounced chiral discrimination between racemic and enantiomerically pure surfactants, favoring heterochiral discrimination. The monolayers were also investigated with Brewster angle microscopy (BAM) and grazing incidence X-ray diffraction (GIXD). It was not possible to observe any chirality dependent features from the BAM images, but the GIXD measurement supported the conclusion that heterochiral discrimination governed the intermolecular forces within the racemic monolayer. The third class of surfactants, containing an amide linkage between the glucose units and 12-hydroxy stearic acid was evaluated with respect to the CMC and the haemolytic activity. These surfactants were all haemolytic close to their respective CMC. / QC 20101015

Herein are presented collective studies of amino acid-based surfactants, also known as lipoamino acids, at liquid interfaces. Chapter III describes an investigation of domain morphology of N-Stearoylglutamic acid (N-SGA) Langmuir monolayers at the air/water interface by epifluorescence microscopy. Anisotropic feather-like domains were observed in L-enantiomeric monolayers while symmetric circular domains were found in racemic N-SGA monolayers. At a surface pressure of 30 mN/m the enantiomeric domains melted at 31 ??C while the racemic domains melted at 27 ??C. This result is exactly opposite to the behavior found in bulk crystals where the racemate melts at a higher temperature. These results were explained in terms of different molecular packing and hydrogen bonding between bulk crystals and two-dimensional thin films for enantiomeric and racemic compounds. Chapter IV summarizes the investigations of hydrogen bonding in N-acyl amino acid monolayers by vibrational sum-frequency spectroscopy (VSFS). The intermolecular hydrogen bonding interaction between the adjacent molecules through amide-amide groups in N-stearoylalanine (N-SA) is characterized by an NH stretch peak at 3311 cm-1. This is the first time that the amide NH stretching signals have been detected with the VSFS technique. A similar peak was detected at 3341 cm-1on N-SGA monolayer. The higher frequency indicates that the H-bond strength is weaker due to the larger size of the glutamic acid residue. The NH stretch mode can thus be used as a fingerprint of hydrogen bonding among amide-amide groups. A peak at 3050 cm-1 due to hydrogen bonding among carboxyl groups was also resolved from the VSFS spectra. Molecular models of intermolecular hydrogen bonding were proposed.

<p>I den här avhandlingen har vi studerat hur man kan göra nya tensider. En tensid är en speciell molekyl som har förmågan att lösa sig i både vatten och olja.</p><p>Man kan göra följande experiment hemma: Fyll en glasburk till hälften med vatten och tillsätt en droppe matolja. Oljan bildar en droppe ovanpå vattnet, därför att vatten och olja inte är blandbara. Vatten är polärt och olja är opolärt. Om man rör om med en sked kommer oljedroppen förvisso att dela upp sig i mindre droppar, men så snart man slutar att röra kommer dessa att lägga sig på vattenytan igen. Sätt nu en droppe diskmedel till blandningen och rör om. Nu sprider sig oljedropparna mycket bättre i vattnet, och de lägger sig heller inte på vattenytan lika fort när man slutar att röra. Det här beror på att diskmedel innehåller en tensid, som har en polär och en opolär del. Den polära delen passar ihop med det polära vattnet, medan den opolära delen passar ihop med den opolära oljan. På så vis kan tensiden hjälpa till att lösa upp opolära ämnen i polära vätskor.</p><p>Den aktiva delen av ett läkemedel består ofta av opolära ämnen, vilka inte löser sig i polära vätskor såsom vatten. Eftersom kroppen består till stor del av vatten måste man ändå försöka få läkemedlet vattenlösligt, för att möjliggöra transport via blodet till problemområdet. Det kan man uppnå genom att tillsätta tensider. Om läkemedel-tensidblandningen ska ges till djur eller människor får inte tensiden orsaka någon skada i kroppen.</p><p>Vi har försökt framställa tensider som ska kunna användas för att just lösa läkemedel i vatten. För att kunna framställa nya tensider måste man ha kunskap i organisk syntes. Det betyder att man måste veta hur man från små intermediat (”byggstenar”) successivt kan bygga upp nya molekyler som har de önskvärda egenskaperna. Genom olika typer av organisk syntes har vi byggt upp tre nya tensidtyper, vars egenskaper vi studerat med olika mätningar. Ingen av dessa tensider lämpade sig som tillsats till läkemedel, men vårt arbete har givit mycket ny kunskap om hur framtida tensidmolkyler kan tillverkas och vilka egenskaper de får.</p> / <p>This thesis deals with the synthesis and characterization of new polyhydroxy surfactants. The first part describes the synthesis of three new surfactant classes, and the second part concerns the surface chemical characterization of the synthesized surfactants.</p><p>A stereodivergent route for preparation of hydrophilic head groups was developed, that featured consecutive stereoselective dihydroxylations of a diene. This method provided in total four different polyhydroxylated head groups. These surfactant head groups were natural and unnatural sugar analogues, and were used for the coupling with two different hydrophobic tail groups.</p><p>Another approach took advantage of a metathesis reaction and provided a polyhydroxylated compound that was coupled to 12-hydroxy stearic acid</p><p>The third class of surfactants contained an amide linkage between the hydrophilic and the hydrophobic parts. The hydrophilic part consisted of two glucose units, and 12-hydroxy stearic acid was used as the hydrophobic part. The hydroxy moiety in the tail group was further functionalized as aliphatic esters, which provided in total four different surfactants.</p><p>A selection of the surfactants was used to investigate the chiral discrimination in Langmuir monolayers at an air-water interface. The isotherms showed a remarkable difference in compressibility between diastereomeric surfactants and also a pronounced chiral discrimination between racemic and enantiomerically pure surfactants, favoring heterochiral discrimination. The monolayers were also investigated with Brewster angle microscopy (BAM) and grazing incidence X-ray diffraction (GIXD). It was not possible to observe any chirality dependent features from the BAM images, but the GIXD measurement supported the conclusion that heterochiral discrimination governed the intermolecular forces within the racemic monolayer.</p><p>The third class of surfactants, containing an amide linkage between the glucose units and 12-hydroxy stearic acid was evaluated with respect to the CMC and the haemolytic activity. These surfactants were all haemolytic close to their respective CMC.</p>

This thesis involves the synthesis of two main classes of triaminocyclopropenium (tac) Ionic Liquids (ILs) (i) Amino Acid Ionic Liquids (AAILs) and (ii) reduced-symmetry cations. [C₃(NEt₂)₂(NRR’)]X (X = TFSA and MeSO₄) were prepared, whereby NHR is derived from amino acids. Optically pure AAILs, [E₄AminoAcid]X (X = TFSA and MeSO₄) were obtained as a mixture of the IL and its zwitterion. The ratios of these mixtures were determined by pH titration and microanalysis. The AAILs specific rotations and pKa values were determined. AAILs can be used for chiral discrimination and form diasterreomeric salts with the entioenriched sodium salt of Mosher’s acid. The AAILs were also successfully used as a solvent and/or catalyst in an aldol reaction and a Diels-Alder reaction. The low-molecular weight series, [C₃(NMe₂)₂(NRR’)]X and [C₃(NMe₂)₂(NR’2)]X was synthesized and characterized: protic ILs NRR’, where R = ethyl, propyl, allyl, butyl, - CH2CH2OCH₃ and pentyl, R’ = H and X = TFSA: and aprotic ILs NRR’, where R = Me, R’ = ethyl, allyl, propyl, butyl, -CH2CH2OCH₃ and hexyl and X = TFSA and DCA. ILs with C2v symmetry [C₃(NEt₂)₂(NH2)]X (X = TFSA and MeSO₄), [C₃(NEt₂)₂(NBu2)]I, [C₃(NEt₂)₂(NHex₂)]I and [C₃(NEt₂)₂(NHex₂)]OTf were also synthesized and characterized. The C₃h cations, [C₃(NMeR)₃]X (R = ethyl, allyl, -CH2CH2OCH₃ and phenyl, X = TFSA and DCA) were successfully prepared as well. The D₃h cation salts [C₃(NEt₂)₃]X (X = MeC6H4SO₃, OTf, I and F5C6O) and [C₃(NBu2)₃]X (X = B(CN)4 and FAP) were also prepared. The tac-based ILs [C₃(NEt₂)₃]+ and [C₃(NBu2)₃]+ were also complexed with metal halides - - 2- 2- forming salts with FeCl₄ , SnCl₃ , CuCl₄ and ZnCl₄ . Reaction of pentachlorocyclopropane (C₃Cl5H) with BuNH2 gave the open ring allylium product [H2C₃(NBuH)4]2+. This was characterized as Cl- and TFSA- salt. During the synthesis of [C₃(NMe₂)₃]Cl, the open ring cation [HC₃(NMe₂)4]+ was also isolated and was characterized as the TFSA- salt. XX Abstract The TGA, DSC, density, viscosity, conductivity, and molar conductivity properties for the ILs were measured where possible. The viscosity and conductivity data was fitted for the Arrhenius and Vogel-Fulcher Tamman equations. The entire tac-based ILs lie below the KCl ideal line in Walden plot. A fragility plot was obtained by fitting the viscosity data and all the tac-based ILs were fragile. The crystal structures of [C₃(NPhH)₃]TFSA, [C₃(NEt₂)₃]FeCl₄ and [HC₃(NMe₂)4]Cl.2CH₃Cl were determined.

This thesis deals with the synthesis and characterization ofnovel polyhydroxyl surfactants. The first part describes thesynthesis of a number of stereoisomers of a polyhydroxylsurfactant, and the second part concerns surface chemicalcharacterization. A stereodivergent route for preparation of the hydrophilichead group was developed, featuring consecutive stereoselectivedihydroxylations of a diene. This afforded in total fourdifferent polyhydroxyl head groups. These surfactant headgroups were natural and unnatural sugar analogues, and wereused for the coupling with two different hydrophobic tailgroups. Three of these surfactants were used to investigate thechiral discrimination in Langmuir monolayers at an air-waterinterface. The isotherms showed a remarkable difference incompressibility between surfactants of diastereomericrelationship and also a pronounced chiral discriminationbetween racemic and enantiomerically pure surfactants favoringheterochiral discrimination. / <p>NR 20140805</p>

No description available.

This thesis is about excitation, detection, properties and applications of multiple quantum coherences applied to different dipolar coupled spin systems. Major focus of the work is on spectral simplification, measurement of residual dipolar couplings and discrimination of enantiomers in chiral aligning media. The first chapter gives a brief account on the fundamentals of nuclear magnetic resonance spectroscopy and multiple quantum coherences. This includes a description of product operator and polarization operator formalisms of pulses and evolution of magnetization. Subsequently a detailed account of two dimensional multiple quantum – single quantum (MQ-SQ) correlation experiments is given. Demonstration of the homonuclear MQ-SQ pulse sequence on a weakly coupled spin system and analysis of the spectrum obtained are also discussed. Homo-nuclear multiple quantum studies carried out to obtain relative the signs of the couplings have been reported in the initial part of the second chapter. The technique has been applied on doubly labeled acetonitrile (13CH313C15N) aligned in a liquid crystalline medium. Special situations like ambiguity in the determination of relative signs of the couplings from the appearance of two dimensional MQ-SQ spectra and the explanation for the same are also discussed. Homo-nuclear MQ experiments on indistinguishable spins, like protons in a methyl group of 13CH313C15N oriented in liquid crystal, and distinguishable spins, like the two carbons in the same molecule, have been carried out. Different directions of approach in which these results need to be analyzed have been discussed. Subsequent part of the chapter is about the correlation of connected MQ-SQ coherences. These experiments are significant in reducing the cross-peaks further from the MQ-SQ spectra. This concept is extended for the discrimination of optical enantiomers dissolved in chiral aligning medium made of poly-Γ-benzyl-L-glutamate (PBLG) and CDCl3. In molecules of Chemical and biological interest one encounters several nuclei such as, 1H, 13C, 15N and 19F. It will be of general interest to determine magnitudes and relative signs of the couplings among these coupled nuclei by NMR experiments. Utilization of hetero-nuclear MQ Experiments in solving such problems is discussed in the third Chapter. Hetero-nuclear MQ experiments were carried out on dipolar coupled 13CH313C15N, with the aim of obtaining the values and signs of various hetero-nuclear couplings in the molecule. The splitting of transitions in the spectra of oriented molecules is always influenced by the sum of dipolar and scalar couplings. Hence precise determination of dipolar couplings requires the knowledge of scalar couplings. To determine the J couplings, experiments were carried out on the same molecule in isotropic medium. When many coupled nuclei are involved one has to carry out several experiments to derive all the spectral parameters. In circumventing this problem heteronuclear multiple quantum experiments involving more than two nuclei as active spins are advantageous. This reduces the number of experiments and thereby reducing the total experimental time. Second part of this chapter demonstrates how a triple resonance triple quantum experiment can provide majority of the couplings from a given coupled system. The feasibility of the experiment is demonstrated even for molecules containing natural abundant isotopes. Application of multiple quantum j-resolved technique for chiral discrimination and obtaining complete one dimensional spectrum of each enantiomer from their racemic mixture is discussed in the fourth chapter. The two dimensional experiment consists of a selective double quantum excitation period followed by selective refocusing during indirect time domain, isotropic mixing and nonselective detection of SQ transitions. Hence this pulse sequence is named as DQSERF-COSY (Double Quantum Selective Refocused Correlation Spectroscopy). The experiment exploits the existence of different intra-methyl couplings between the enantiomers dissolved in chiral liquid crystal medium to separate the one dimensional spectra of each enantiomer in different cross sections. This is possible due to the fact that all the nuclei in any one of the enantiomers are coupled among themselves and there is no inter molecular interaction between the two enantiomers. Also one can extract all the couplings between protons in each enantiomer, which can subsequently be utilized for determination of the residual dipolar couplings, structure and orientation parameters.

The research work reported in this thesis deals with the development of novel NMR experimental techniques for the spectroscopic discrimination of enantiomers dissolved in a chiral liquid crystalline medium. The information on the chemical shifts and coupling constants pertaining to each enantiomer has been derived on the investigated chiral molecules. The enantiomeric excess (ee), a parameter which is of profound importance in pharmaceutical industry and in asymmetric synthesis, has also been measured. A special attention is paid to the use of high sensitivity of H NMR for chiral discrimination. Typical analyses of H NMR spectra are severely hindered due to enormous spectral inhomogeneous broadening arising from too many unresolved transitions, in addition to superposition of spectra from both the enantiomers. Therefore, the major part of the work is focused on the design and application of pulse sequences to overcome many of these drawbacks. This helps to achieve very high resolution, discerning of overlapped transitions, identification of resonances pertaining to each enantiomer and simplification of the spectrum for easy extraction of spectral parameters, in addition to the accurate measurement of ee. Initially a brief discussion is provided on enantiomers, diastereomers, basic principles of NMR spectroscopy, the several interaction Hamiltonians responsible for yielding the NMR spectra, introduction to product and polarization operator formalisms that gives insight into the spin dynamics for designing appropriate two-dimensional (2D) NMR experiments. This sets the foundation to understand the complex multiplet structures of the diagonal peaks and cross peaks in the resulting 2D spectrum. Subsequently, a brief introduction is given for the available techniques for NMR spectroscopic discrimination of enantiomers in isotropic medium, where only chemical shifts are employed as a measurable parameter. The limitations of these techniques are circumvented by the introduction of other anisotropic NMR parameters, such as homo-and hetero-nuclear dipolar couplings, quadrupolar couplings and chemical shift anisotropies. To achieve this goal the enantiomers are dissolved in weakly aligning chiral liquid crystalline (CLC) medium. To understand this, a general introduction to liquid crystals and their utility as an alignment medium in NMR spectroscopy and the anisotropic interactions affecting the NMR spectrum has also been provided. The preparation of the CLC phase of Poly-γ-Benzyl-L-Glutamate (PBLG) employed in the present study and its orientational behaviour has been discussed. The detection of NMR spectra of various nuclei and the interaction parameters utilized for chiral discrimination will be enumerated. A brief summary of the experiments employed for the spectral analyses of the enantiomers dissolved in PBLG will also be presented.