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1,3,5-Triferrocenyl-2,4,6-tris(ethynylferrocenyl)-benzene – a new member of the family of multiferrocenyl-functionalized cyclic systemsPfaff, Ulrike, Filipczyk, Grzegorz, Hildebrandt, Alexander, Korb, Marcus, Lang, Heinrich 19 September 2014 (has links) (PDF)
The consecutive synthesis of 1,3,5-triferrocenyl-2,4,6-tris(ethynylferrocenyl)benzene (6c) is described using 1,3,5-Cl3-2,4,6-I3-C6 (2) as starting compound. Subsequent Sonogashira C,C cross-coupling of 2 with FcC[triple bond, length as m-dash]CH (3) in the molar ratio of 1 : 4 afforded solely 1,3,5-Cl3-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (4c) (Fc = Fe(η5-C5H4)(η5-C5H5)). However, when 2 is reacted with 3 in a 1 : 3 ratio a mixture of 1,3,5-Cl3-2-(FcC[triple bond, length as m-dash]C)-4,6-I2-C6 (4a) and 1,3,5-Cl3-2,4-(FcC[triple bond, length as m-dash]C)2-6-I-C6 (4b) is obtained. Negishi C,C cross-coupling of 4c with FcZnCl (5) in the presence of catalytic amounts of [Pd(CH2C(CH3)2P(tC4H9)2)(μ-Cl)]2 gave 1,3-Cl2-5-Fc-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (6a), 1-Cl-3,5-Fc2-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (6b) and 1,3,5-Fc3-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (6c) of which 6b is the main product. Column chromatography allowed the separation of these organometallic species. The structures of 4a,b and 6a in the solid state were determined by single crystal X-ray diffractometry showing a π–π interacting dimer (4b) and a complex π–π pattern for 6a. The electrochemical properties of 4a–c and 6a–c were studied by cyclic voltammetry (=CV) and square wave voltammetry (=SWV). It was found that the FcC[triple bond, length as m-dash]C-substituted benzenes 4a–c show only one reversible redox event, indicating a simultaneous oxidation of all ferrocenyl units, whereby 4c is most difficult to oxidise (4a, E°′1 = 190, ΔEp = 71; 4b, E°′1 = 195, ΔEp = 59; 4c, E°′1 = 390, ΔEp = 59 mV). In case of 4c, the oxidation states 4cn+ (n = 2, 3) are destabilised by the partial negative charge of the electronegative chlorine atoms, which compensates the repulsive electrostatic Fc+–Fc+ interactions with attractive electrostatic Fc+–Clδ− interactions. When ferrocenyl units are directly attached to the benzene C6 core, organometallic 6a shows three, 6b five and 6c six separated reversible waves highlighting that the Fc units can separately be oxidised. UV-Vis/NIR spectroscopy allowed to determine IVCT absorptions (=Inter Valence Charge Transfer) for 6cn+ (n = 1, 2) (n = 1: νmax = 7860 cm−1, εmax = 405 L mol−1 cm−1, Δν1/2 = 7070 cm−1; n = 2: νmax = 9070 cm−1, εmax = 620 L mol−1 cm−1, Δν1/2 = 8010 cm−1) classifying these mixed-valent species as weakly coupled class II systems according to Robin and Day, while for 6a,b only LMCT transitions (=ligand to metal charge transfer) could be detected. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Vliv magnetického pole a dalších vybraných stresorů na fyziologii mikrobiálních buněk / The effect of magnetic field and other selected stressors on physiology of bacterial cellsMrázová, Kateřina January 2019 (has links)
This thesis deals with the effect of magnetic field and organic substances, namely benzene and p-nitrophenol, on cell of PHA producing bacteria Cupriavidus necator H16 and mutant strain Cupriavidus necator PHB4, which does not produce polyhydroxyalkanoates. Static magnetic field was generated by both permanent magnet and electromagnet. The effect of magnetic field on the growth of bacterial cells was studied using growth curves. It was found that cultivation in magnetic field and mineral medium mostly inhibits bacterial growth. Also the amount of polyhydroxyalkanoates was observed using FT-IR, flow cytometry and microscopy with fluorescent dye. Growth curves and flow cytometry were also used to study the influence of organic substances on bacterial cells. It was found that while benzene does not affect either C. necator H16 or C. necator PHB4, p-nitrophenol acts as the inhibitor of bacterial growth for both cultures. Finally the impact of p-nitrophenol on the accumulation of PHA was studied using gas chromatography.
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Benzen v benzinech z hlediska ochrany zdraví / Benzene in petroleum-derived products and health protectionBílková, Karolina January 2008 (has links)
Benzene is very toxic compound, which has carcinogenic and mutagenic effects. Result of these effects is significant reduction of its use and also low hygienic limits in occupational environment and environment. The aim of this diploma thesis was to map out possible exposure to benzene and checking of clasification correctness of motor gasoline and benzine (cleaners, thinners etc.). Determination of benzene was carried out by gas chromatography with flame ionisation detector (GC/FID) and high performance liquid chromatography with diod array detector (HPLC/DAD). Marginally, the diploma thesis was focused on determination of toluene (in june 2007 became effective ordinance no.284/2006 Sb., which forbid to sell products that contain more than 0,1 % of toluene to small consumers). Toluene was determined by same methods as benzene.
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Nové způsoby vzorkování pro vyhodnocení reálných remediačních studií / New sampling approaches for evaluation of real remediation studiesKroupová, Kristýna January 2017 (has links)
This diploma thesis has been carried out as a part of the project Utilization of long term (passive) sampling methods combined with in situ microcosms for assessment of (bio)degradation potential (PASSES). In the frame of the project groundwater remediation took place in the premises of Farmak a.s. in Olomouc using a pilot photooxidation unit and efficiency of the remediation was monitored through passive and active sampling methods. Pilot photooxidation unit is a technology based on the H2O2/UV-C photochemical oxidation of organic pollutants. In this work optimization tests of the pilot photooxidation unit were performed. The residence time of the groundwater in the photoreactors, required for its sufficient decontamination from pharmaceuticals and aromatic hydrocarbons, was 2.5 hours. 91% degradation of the pharmaceuticals and 80% degradation of aromatic hydrocarbons were reached during this interval. Although the removal efficiency of the pharmaceuticals by the photooxidation unit was high, the pilot photooxidation unit was not able to effectively remove the pharmaceuticals at the studied locality. By comparing the results of the pharmaceuticals from active and passive groundwater sampling during the remediation attempt, passive Polar Organic Chemical Integrative Sampler (POCIS) was found to be...
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1,3,5-Triferrocenyl-2,4,6-tris(ethynylferrocenyl)-benzene – a new member of the family of multiferrocenyl-functionalized cyclic systemsPfaff, Ulrike, Filipczyk, Grzegorz, Hildebrandt, Alexander, Korb, Marcus, Lang, Heinrich 19 September 2014 (has links)
The consecutive synthesis of 1,3,5-triferrocenyl-2,4,6-tris(ethynylferrocenyl)benzene (6c) is described using 1,3,5-Cl3-2,4,6-I3-C6 (2) as starting compound. Subsequent Sonogashira C,C cross-coupling of 2 with FcC[triple bond, length as m-dash]CH (3) in the molar ratio of 1 : 4 afforded solely 1,3,5-Cl3-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (4c) (Fc = Fe(η5-C5H4)(η5-C5H5)). However, when 2 is reacted with 3 in a 1 : 3 ratio a mixture of 1,3,5-Cl3-2-(FcC[triple bond, length as m-dash]C)-4,6-I2-C6 (4a) and 1,3,5-Cl3-2,4-(FcC[triple bond, length as m-dash]C)2-6-I-C6 (4b) is obtained. Negishi C,C cross-coupling of 4c with FcZnCl (5) in the presence of catalytic amounts of [Pd(CH2C(CH3)2P(tC4H9)2)(μ-Cl)]2 gave 1,3-Cl2-5-Fc-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (6a), 1-Cl-3,5-Fc2-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (6b) and 1,3,5-Fc3-2,4,6-(FcC[triple bond, length as m-dash]C)3-C6 (6c) of which 6b is the main product. Column chromatography allowed the separation of these organometallic species. The structures of 4a,b and 6a in the solid state were determined by single crystal X-ray diffractometry showing a π–π interacting dimer (4b) and a complex π–π pattern for 6a. The electrochemical properties of 4a–c and 6a–c were studied by cyclic voltammetry (=CV) and square wave voltammetry (=SWV). It was found that the FcC[triple bond, length as m-dash]C-substituted benzenes 4a–c show only one reversible redox event, indicating a simultaneous oxidation of all ferrocenyl units, whereby 4c is most difficult to oxidise (4a, E°′1 = 190, ΔEp = 71; 4b, E°′1 = 195, ΔEp = 59; 4c, E°′1 = 390, ΔEp = 59 mV). In case of 4c, the oxidation states 4cn+ (n = 2, 3) are destabilised by the partial negative charge of the electronegative chlorine atoms, which compensates the repulsive electrostatic Fc+–Fc+ interactions with attractive electrostatic Fc+–Clδ− interactions. When ferrocenyl units are directly attached to the benzene C6 core, organometallic 6a shows three, 6b five and 6c six separated reversible waves highlighting that the Fc units can separately be oxidised. UV-Vis/NIR spectroscopy allowed to determine IVCT absorptions (=Inter Valence Charge Transfer) for 6cn+ (n = 1, 2) (n = 1: νmax = 7860 cm−1, εmax = 405 L mol−1 cm−1, Δν1/2 = 7070 cm−1; n = 2: νmax = 9070 cm−1, εmax = 620 L mol−1 cm−1, Δν1/2 = 8010 cm−1) classifying these mixed-valent species as weakly coupled class II systems according to Robin and Day, while for 6a,b only LMCT transitions (=ligand to metal charge transfer) could be detected. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Role of deposition temperature and concentration on the self-assembly and reaction of organic molecules at the solution-graphite interfaceNguyen, Doan Chau Yen 25 April 2017 (has links) (PDF)
Das Hauptthema dieser Dissertation ist die Untersuchung der Selbstorganisation organischer Moleküle an der Flüssig-Fest-Grenzfläche (LSI). Besondere Betonung liegt auf der Kontrolle der Selbstassemblierung durch geeignete Parameter: die Substrattemperatur während der Abscheidung, die Konzentration der gelösten Moleküle, und die chemische Natur der gelösten Stoffe und Lösungsmittel. Die Untersuchungen wurden unter Verwendung der Rastertunnelmikroskopie (STM) durchgeführt. Der erste Schwerpunkt dieser Arbeit ist die systematische Untersuchung der Auswirkung erhöhter Substrattemperatur während der Abscheidung aus der Lösung auf die Selbstorganisation komplexer molekularer Architekturen an der LSI. Diese Untersuchungen wurden mit dem planaren Molekül Trimesinsäure (TMA), sowie dem nicht-planaren Molekül Benzen-1,3,5-triphosphonsäure (BTP) durchgeführt. Es wird gezeigt, dass der Polymorphismus der Adsorbatstrukturen von TMA und BTP durch die Substrattemperatur während der Abscheidung der Moleküle aus der Lösung für verschiedene Lösungsmitteln unterschiedlicher Polarität, wie Phenyloctan, Octansäure und Undecanol, kontrolliert werden kann. Durch die Erhöhung der Temperatur des vorgeheiztem Graphitsubstrates kann die spezifische 2D supramolekulare Struktur and die entsprechende Packungsdichte der Moleküle in der Adsorbatschicht für jedes der untersuchten Lösungsmittel präzise eingestellt werden. Weiterhin wird der Einfluss der Konzentration auf die resultierende Anordnung der TMA Moleküle an der LSI durch ein weiteres Experiment abgeschätzt, bei welchem Rühren (von 0 h bis 40 h) der Lösungen mit verschiedenen Lösungsmitteln eingesetzt wurde. Diese Ergebnisse zeigen, dass die verschiedenen Präparationsmethoden (Erhöhung der Abscheidetemperatur oder Rühren) zu derselben Tendenz der Änderung der geordneten Strukturen sowie der Packungsdichte führt, weswegen man schlussfolgern kann, dass die Erhöhung der Konzentration an der LSI bei erhöhter Abscheidetemperatur ebenso der Hauptgrund für die beobachteten Änderungen ist. Der zweite Schwerpunkt dieser Dissertation ist die Untersuchung von chemischen Reaktionen der selbstassemblierenden Moleküle. Eine Veresterungsreaktion von TMA mit Undecanol wurde gefunden. Weiterhin wurde, als ein erster Schritt zur Untersuchung der Zwillingspolymerisation, die Oligomerisation des Zwillingsmonomers 2,2’-spirobi [4H-1,3,2-benzo-dioxasiline] (SBS) mit STM an der Grenzfläche zwischen der SBS-Undecanol-Lösung und einer Graphitoberfläche untersucht. Erstens wurde durch Ultraschallbehandlung der SBS Lösung in Undecanol für verschieden lange Zeiten die Oligomerisation der SBS Monomere ohne einen Katalysator an der LSI beobachtet. Zweitens konnte die Oligomerisation auch durch Erhöhung der Substrattemperatur während der Abscheidung der Moleküle aus der Lösung initiiert werden. Durch die schrittweise Erhöhung der Temperatur des vorgeheizten Substrates konnten mehrere, verschiedene, periodische Anordnungen von Phenol‒Dimeren, ‒Trimeren, und –Pentameren u.s.w. gefunden werden. Weiterhin wird die Auswirkung der Abscheidetemperatur auf die Selbstorganisation an der LSI nur der Lösungsmittelmoleküle aus dem reinen Lösungsmittel beschrieben. Dies ist wichtig, da die Undecanol‒Moleküle stets mit den gelösten, in dieser Arbeit verwendeten Stoffen (TMA, BTP, SBS) koadsorbieren und lineare Muster bilden. / The main aim of this thesis is to study the self-assembly of organic molecules at the liquid-solid interface (LSI). Special emphasis is given to controlling the process of self-assembly via suitable parameters such as: the substrate temperature during the initial deposition, the concentration of dissolved molecules, or the chemical nature of solutes and solvents. The investigations are performed using scanning tunneling microscopy (STM). The first focus of this work is the systematic investigation of the effect of the substrate temperature during the deposition out of the solution on the self-assembly of complex molecular architectures at the LSI. These investigations have been done with the planar molecule trimesic acid (TMA), and the non-planar molecule benzene 1,3,5-triphosphonic acid (BTP). We show that the polymorphism of the adsorbate structures of TMA (also with BTP) can be controlled by the substrate temperature during the deposition of the molecules out of the solution for various solvents of different polarity such as phenyloctane, octanoic acid, and undecanol. By increasing the temperature of the pre-heated graphite substrate, the specific 2D supramolecular structure and the corresponding packing density in the adsorbate layer can be precisely tuned for each kind of the solvents studied. Furthermore, the influence of the concentration on the resulting self-assembly of TMA molecules at the LSI is estimated by another experiment using stirring (from 0 h to 40 h) of the solutions of different kinds of solvents. These results demonstrate that choosing different preparation methods (increasing deposition temperatures or stirring) lead to the same tendency in the change of the self-assembled structures as well as the tuning of the packing density from which it can also be concluded that the increase of the concentration at increased deposition temperatures is also the main reason for the observed changes. The second focus of this work is the investigation of chemical reactions of self-assembling molecules. The esterification of TMA with undecanol was observed. Moreover as a first step to study twin polymerization, the oligomerization of the twin monomer 2,2’-spirobi [4H-1,3,2-benzo-dioxasiline] (SBS) was investigated by STM at the SBS-undecanol solution/graphite interface. Firstly, by ultrasonicating the solution of SBS in undecanol for different times the oligomerization of SBS monomer without any catalyst has been observed at the LSI. Secondly, the oligomerization of SBS monomer can also be initiated by the substrate temperature during the deposition of the molecules out of the solution. By stepwise increasing the temperature of the pre-heated substrate, various periodic assemblies of phenolic dimer, trimer, pentamer resin, and so on were observed. Furthermore, the effect of deposition temperature on the self-assembly of solely solvent molecules from the pure liquid at the LSI is described, which is important because the undecanol solvent molecules are always co-adsorbed with the solutes used in this work (TMA, BTP, SBS) to form linear patterns.
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Role of deposition temperature and concentration on the self-assembly and reaction of organic molecules at the solution-graphite interfaceNguyen, Doan Chau Yen 17 January 2017 (has links)
Das Hauptthema dieser Dissertation ist die Untersuchung der Selbstorganisation organischer Moleküle an der Flüssig-Fest-Grenzfläche (LSI). Besondere Betonung liegt auf der Kontrolle der Selbstassemblierung durch geeignete Parameter: die Substrattemperatur während der Abscheidung, die Konzentration der gelösten Moleküle, und die chemische Natur der gelösten Stoffe und Lösungsmittel. Die Untersuchungen wurden unter Verwendung der Rastertunnelmikroskopie (STM) durchgeführt. Der erste Schwerpunkt dieser Arbeit ist die systematische Untersuchung der Auswirkung erhöhter Substrattemperatur während der Abscheidung aus der Lösung auf die Selbstorganisation komplexer molekularer Architekturen an der LSI. Diese Untersuchungen wurden mit dem planaren Molekül Trimesinsäure (TMA), sowie dem nicht-planaren Molekül Benzen-1,3,5-triphosphonsäure (BTP) durchgeführt. Es wird gezeigt, dass der Polymorphismus der Adsorbatstrukturen von TMA und BTP durch die Substrattemperatur während der Abscheidung der Moleküle aus der Lösung für verschiedene Lösungsmitteln unterschiedlicher Polarität, wie Phenyloctan, Octansäure und Undecanol, kontrolliert werden kann. Durch die Erhöhung der Temperatur des vorgeheiztem Graphitsubstrates kann die spezifische 2D supramolekulare Struktur and die entsprechende Packungsdichte der Moleküle in der Adsorbatschicht für jedes der untersuchten Lösungsmittel präzise eingestellt werden. Weiterhin wird der Einfluss der Konzentration auf die resultierende Anordnung der TMA Moleküle an der LSI durch ein weiteres Experiment abgeschätzt, bei welchem Rühren (von 0 h bis 40 h) der Lösungen mit verschiedenen Lösungsmitteln eingesetzt wurde. Diese Ergebnisse zeigen, dass die verschiedenen Präparationsmethoden (Erhöhung der Abscheidetemperatur oder Rühren) zu derselben Tendenz der Änderung der geordneten Strukturen sowie der Packungsdichte führt, weswegen man schlussfolgern kann, dass die Erhöhung der Konzentration an der LSI bei erhöhter Abscheidetemperatur ebenso der Hauptgrund für die beobachteten Änderungen ist. Der zweite Schwerpunkt dieser Dissertation ist die Untersuchung von chemischen Reaktionen der selbstassemblierenden Moleküle. Eine Veresterungsreaktion von TMA mit Undecanol wurde gefunden. Weiterhin wurde, als ein erster Schritt zur Untersuchung der Zwillingspolymerisation, die Oligomerisation des Zwillingsmonomers 2,2’-spirobi [4H-1,3,2-benzo-dioxasiline] (SBS) mit STM an der Grenzfläche zwischen der SBS-Undecanol-Lösung und einer Graphitoberfläche untersucht. Erstens wurde durch Ultraschallbehandlung der SBS Lösung in Undecanol für verschieden lange Zeiten die Oligomerisation der SBS Monomere ohne einen Katalysator an der LSI beobachtet. Zweitens konnte die Oligomerisation auch durch Erhöhung der Substrattemperatur während der Abscheidung der Moleküle aus der Lösung initiiert werden. Durch die schrittweise Erhöhung der Temperatur des vorgeheizten Substrates konnten mehrere, verschiedene, periodische Anordnungen von Phenol‒Dimeren, ‒Trimeren, und –Pentameren u.s.w. gefunden werden. Weiterhin wird die Auswirkung der Abscheidetemperatur auf die Selbstorganisation an der LSI nur der Lösungsmittelmoleküle aus dem reinen Lösungsmittel beschrieben. Dies ist wichtig, da die Undecanol‒Moleküle stets mit den gelösten, in dieser Arbeit verwendeten Stoffen (TMA, BTP, SBS) koadsorbieren und lineare Muster bilden.:Chapter 1: Introduction
Chapter 2: Basic principle
2.1 Principles of scanning tunneling microscopy (STM)
2.1.1 General working principle
2.1.2 Tunneling effect
2.1.3 Theory of STM
2.1.4 Contrast mechanism of molecular adsorbates
2.1.5 Modes of STM operation
2.2 STM at the liquid-solid interface (LSI)
2.3 Thermodynamics and kinetics
2.3.1 Equilibrium of the adsorption/desorption and initial agglomeration at the LSI
2.3.2 Kinetic and thermodynamic control over 2D molecular self-assembly
2.4 Experimental condition
2.4.1 Role of solvent
2.4.2 Role of concentration
2.4.3 Role of temperature
References
Chapter 3: Experimental section
3.1 Solutes
3.1.1 Trimesic acid (TMA) (1,3,5?C6H3(COOH)3)
3.1.2 Benzene 1.3.5-Triphosphonic acid (BTP) (1,3,5?C6H3(PO3H2)3)
3.1.3 Twin monomer 2,2’-spirobi[4H-1,3,2-benzo-dioxasiline] (SBS)
3.2 Solvents
3.3 Substrate: Highly oriented pyrolytic graphite (HOPG (0001))
3.4 Preparation of the STM tips
3.5 Experimental methods for sample preparation
3.5.1 Preparation of the solution
3.5.2 Heating of the substrate
3.5.3 Ultrasonication
3.5.4 Stirring
3.6 Computational details
References
Chapter 4: Deposition temperature? and solvent-dependent 2D supramolecular assemblies of trimesic acid at the liquid-graphite interface revealed by STM
Results and discussion
4.1 Hydrogen bonding motifs of trimesic acid molecules
4.2 TMA deposited from solution in octanoic acid
4.3 TMA deposited from solution in phenyloctane
4.4 TMA deposited from solution in undecanol
4.6 Discussion of the solute–solvent interactions
4.5 Effect of the deposition substrate temperature on the formation of ester at the LSI of TMA in undecanol
Conclusion
References
Chapter 5: Role of concentration on the self-assembly of TMA at the LSI influenced by stirring time
Results and discussion
5.1 TMA in octanoic acid
5.2 TMA in phenyloctane
5.3 TMA in undecanol
Conclusion
References
Chapter 6: Role of deposition temperature on the self-assembly of the non-planar molecule benzene- 1,3,5- triphosphonic acid (BTP) at the LSI
Results and discussion
6.1 BTP in undecanol at room temperature
6.2 BTP in undecanol at high substrate temperature during deposition
Conclusion
References
Chapter 7: Role of deposition temperature on the self-assembly of pure undecanol solvent at the LSI
Results and discussion
7.1 Adsorption geometry of undecanol on HOPG
7.2 Herringbone structures of undecanol
7.3 Parallel structure of undecanol at high substrate temperature during deposition
Conclusion
References
Chapter 8: A first step to microscopically study twinpolymerization: self-assembly of twin monomer 2,2’-Spirobi[4H-1,3,2-benzo-dioxasiline] (SBS) at the LSI influenced by ultrasonication and deposition substrate temperature
8.1 Coadsorption of SBS and undecanol without ultrasonication and at room temperature
8.2 SBS deposited from solution in undecanol in dependence on the duration of ultrasonication
8.3 SBS deposited from solution in undecanol
at varied deposition temperature of the substrate
8.4 Discussion and open questions
Appendix
References
CHAPTER 9: SUMMARY AND OUTLOOK
ERKLÄRUNG
CURRICULUM VITAE
ACKNOWLEDGEMENT / The main aim of this thesis is to study the self-assembly of organic molecules at the liquid-solid interface (LSI). Special emphasis is given to controlling the process of self-assembly via suitable parameters such as: the substrate temperature during the initial deposition, the concentration of dissolved molecules, or the chemical nature of solutes and solvents. The investigations are performed using scanning tunneling microscopy (STM). The first focus of this work is the systematic investigation of the effect of the substrate temperature during the deposition out of the solution on the self-assembly of complex molecular architectures at the LSI. These investigations have been done with the planar molecule trimesic acid (TMA), and the non-planar molecule benzene 1,3,5-triphosphonic acid (BTP). We show that the polymorphism of the adsorbate structures of TMA (also with BTP) can be controlled by the substrate temperature during the deposition of the molecules out of the solution for various solvents of different polarity such as phenyloctane, octanoic acid, and undecanol. By increasing the temperature of the pre-heated graphite substrate, the specific 2D supramolecular structure and the corresponding packing density in the adsorbate layer can be precisely tuned for each kind of the solvents studied. Furthermore, the influence of the concentration on the resulting self-assembly of TMA molecules at the LSI is estimated by another experiment using stirring (from 0 h to 40 h) of the solutions of different kinds of solvents. These results demonstrate that choosing different preparation methods (increasing deposition temperatures or stirring) lead to the same tendency in the change of the self-assembled structures as well as the tuning of the packing density from which it can also be concluded that the increase of the concentration at increased deposition temperatures is also the main reason for the observed changes. The second focus of this work is the investigation of chemical reactions of self-assembling molecules. The esterification of TMA with undecanol was observed. Moreover as a first step to study twin polymerization, the oligomerization of the twin monomer 2,2’-spirobi [4H-1,3,2-benzo-dioxasiline] (SBS) was investigated by STM at the SBS-undecanol solution/graphite interface. Firstly, by ultrasonicating the solution of SBS in undecanol for different times the oligomerization of SBS monomer without any catalyst has been observed at the LSI. Secondly, the oligomerization of SBS monomer can also be initiated by the substrate temperature during the deposition of the molecules out of the solution. By stepwise increasing the temperature of the pre-heated substrate, various periodic assemblies of phenolic dimer, trimer, pentamer resin, and so on were observed. Furthermore, the effect of deposition temperature on the self-assembly of solely solvent molecules from the pure liquid at the LSI is described, which is important because the undecanol solvent molecules are always co-adsorbed with the solutes used in this work (TMA, BTP, SBS) to form linear patterns.:Chapter 1: Introduction
Chapter 2: Basic principle
2.1 Principles of scanning tunneling microscopy (STM)
2.1.1 General working principle
2.1.2 Tunneling effect
2.1.3 Theory of STM
2.1.4 Contrast mechanism of molecular adsorbates
2.1.5 Modes of STM operation
2.2 STM at the liquid-solid interface (LSI)
2.3 Thermodynamics and kinetics
2.3.1 Equilibrium of the adsorption/desorption and initial agglomeration at the LSI
2.3.2 Kinetic and thermodynamic control over 2D molecular self-assembly
2.4 Experimental condition
2.4.1 Role of solvent
2.4.2 Role of concentration
2.4.3 Role of temperature
References
Chapter 3: Experimental section
3.1 Solutes
3.1.1 Trimesic acid (TMA) (1,3,5?C6H3(COOH)3)
3.1.2 Benzene 1.3.5-Triphosphonic acid (BTP) (1,3,5?C6H3(PO3H2)3)
3.1.3 Twin monomer 2,2’-spirobi[4H-1,3,2-benzo-dioxasiline] (SBS)
3.2 Solvents
3.3 Substrate: Highly oriented pyrolytic graphite (HOPG (0001))
3.4 Preparation of the STM tips
3.5 Experimental methods for sample preparation
3.5.1 Preparation of the solution
3.5.2 Heating of the substrate
3.5.3 Ultrasonication
3.5.4 Stirring
3.6 Computational details
References
Chapter 4: Deposition temperature? and solvent-dependent 2D supramolecular assemblies of trimesic acid at the liquid-graphite interface revealed by STM
Results and discussion
4.1 Hydrogen bonding motifs of trimesic acid molecules
4.2 TMA deposited from solution in octanoic acid
4.3 TMA deposited from solution in phenyloctane
4.4 TMA deposited from solution in undecanol
4.6 Discussion of the solute–solvent interactions
4.5 Effect of the deposition substrate temperature on the formation of ester at the LSI of TMA in undecanol
Conclusion
References
Chapter 5: Role of concentration on the self-assembly of TMA at the LSI influenced by stirring time
Results and discussion
5.1 TMA in octanoic acid
5.2 TMA in phenyloctane
5.3 TMA in undecanol
Conclusion
References
Chapter 6: Role of deposition temperature on the self-assembly of the non-planar molecule benzene- 1,3,5- triphosphonic acid (BTP) at the LSI
Results and discussion
6.1 BTP in undecanol at room temperature
6.2 BTP in undecanol at high substrate temperature during deposition
Conclusion
References
Chapter 7: Role of deposition temperature on the self-assembly of pure undecanol solvent at the LSI
Results and discussion
7.1 Adsorption geometry of undecanol on HOPG
7.2 Herringbone structures of undecanol
7.3 Parallel structure of undecanol at high substrate temperature during deposition
Conclusion
References
Chapter 8: A first step to microscopically study twinpolymerization: self-assembly of twin monomer 2,2’-Spirobi[4H-1,3,2-benzo-dioxasiline] (SBS) at the LSI influenced by ultrasonication and deposition substrate temperature
8.1 Coadsorption of SBS and undecanol without ultrasonication and at room temperature
8.2 SBS deposited from solution in undecanol in dependence on the duration of ultrasonication
8.3 SBS deposited from solution in undecanol
at varied deposition temperature of the substrate
8.4 Discussion and open questions
Appendix
References
CHAPTER 9: SUMMARY AND OUTLOOK
ERKLÄRUNG
CURRICULUM VITAE
ACKNOWLEDGEMENT
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