Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Apr. 15, 2010). Includes bibliographical references.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

The focus of this research is to combine both computational as well as experimental methods to study the non-covalent interaction between a selected set of proteins with small molecules. Experimentally, a mass spectrometric technique, recently known as electrospray mass spectrometry together with the computational aspect of this research, in the area of molecular modeling and quantum mechanics would be exercised.Due to the soft ionization nature of this process, electrospray (ES) mass spectrometry (MS) has been employed to study a broad class of large proteins and their non-covalent interaction with small structures, making it possible for the mass of these complexes to _be determined with an error of less than 0.1%. For this research, a set of proteins known as histones and a class of structures known as crown ethers were chosen. The ES technique allows the proteins to be prepared in an acidic medium that protonates the basic amino acids that have been exposed by the solvent. This process leaves the protein with a lot of positive charges thereby making the analysis with a single quadrupole mass spectrometer, Extrel ELQ 400 possible. The non-covalent complexation between the histones and the crown ethers is stabilized by hydrogen bonding therefore the positive charges of the protein remain unchanged. This bonding is made possible by the ability of crown ethers to bind ammonium ion or protonated amino groups. The mass of the protein which is divided by the number of its positive charges can be determined by a new kind of linear plot constructed from the ES data. The ion currents from the electrospray ionization technique is a representation of the non-covalent complexation of the histones and the crown ethers which can be observed in the mass spectra. Other information such as, the binding constants, can be obtained from the mass spectra. / Department of Chemistry

by Roger Chun Wang Liu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 98-108). / ACKNOWLEDGEMENTS --- p.i / CONTENTS --- p.ii / ABBREVIATIONS --- p.v / LIST OF FIGURES --- p.vi / LIST OF TABLES --- p.vii / Chapter I. --- THE CHEMISTRY OF METALLO-PHTHALOCYANINES AND -NAPHTHALOCYANINES --- p.1 / ABSTRACT --- p.2 / Chapter 1. --- SANDWICH-LIKE BIS(PHTHALOCYANINATO)LANTHANIDE COMPLEXES / Chapter 1.1. --- Introduction --- p.3 / Chapter 1.2. --- Preparation of Substituted Phthalonitriles --- p.8 / Chapter 1.3. --- Condensation of Phthalonitrile --- p.9 / Chapter 1.4. --- Condensation of Substituted Phthalonitriles --- p.10 / Chapter 1.5. --- Spectroscopic and Electrochemical Properties --- p.12 / Chapter 1.6. --- Conclusion --- p.21 / Chapter 2. --- "SUBSTITUTED 2,3-NAPHTHALOCYANINES" / Chapter 2.1. --- Introduction --- p.22 / Chapter 2.2. --- Preparation of Alkyl-Substituted Dicyanonaphthalenes --- p.26 / Chapter 2.3. --- Preparation of Halo-Substituted Dicyanonaphthalenes --- p.30 / Chapter 2.4. --- Condensation of Alkyl-Substituted Dicyanonaphthalenes --- p.30 / Chapter 2.5. --- Condensation of Halo-Substituted Dicyanonaphthalenes --- p.35 / Chapter 2.6. --- Conclusion --- p.38 / Chapter 3. --- EXPERIMENTAL SECTION / Chapter 3.1. --- General Directions --- p.39 / Chapter 3.2. --- Preparation of Substituted Phthalonitriles --- p.40 / Chapter 3.3. --- Condensation of Phthalonitrile --- p.43 / Chapter 3.4. --- Condensation of Substituted Phthalonitriles --- p.44 / Chapter 3.5. --- Preparation of Alkyl-Substituted Dicyanonaphthalenes --- p.46 / Chapter 3.6. --- Preparation of Halo-Substituted Dicyanonaphthalenes --- p.49 / Chapter 3.7. --- Condensation of Alkyl-Substituted Dicyanonaphthalenes --- p.51 / Chapter 3.8. --- Condensation of Halo-Substituted Dicyanonaphthalenes --- p.52 / Chapter II. --- "SYNTHETIC STUDIES OF MIXED AZA-, OXA-, AND THIA-CROWN ETHERS" --- p.55 / ABSTRACT --- p.56 / Chapter 1. --- INTRODUCTION --- p.57 / Chapter 2. --- RESULTS AND DISCUSSION --- p.64 / Chapter 2.1. --- Preparation of Diols and Dithiols --- p.64 / Chapter 2.2. --- Preparation of Ditosylates --- p.66 / Chapter 2.3. --- 1:1 Cyclization -- Preparation of Monoaza- 15-crown-5 --- p.68 / Chapter 2.4. --- Crystal Structure of N-(4-methoxyphenyl) benzomonoaza-15- crown-5 (112) --- p.76 / Chapter 2.5. --- Complexation of Monoaza-15-crown-5 --- p.79 / Chapter 2.6. --- Conclusion --- p.80 / Chapter 3. --- MISCELLANEOUS SYNTHESES --- p.81 / Chapter 3.1. --- Preparation of Tetrabromodibenzo-24-crown-8 --- p.81 / Chapter 3.2. --- Complexation of Tetrabromodibenzo-24-crown-8 --- p.82 / Chapter 4. --- EXPERIMENTAL SECTION --- p.84 / Chapter 4.1. --- General Directions --- p.84 / Chapter 4.2. --- Preparation of Diols and Dithiols --- p.84 / Chapter 4.3. --- Preparation of Ditosylates --- p.88 / Chapter 4.4. --- 1:1 Cyclization -- Preparation of Monoaza- 15-crown-5 --- p.89 / Chapter 4.5. --- Complexation of Monoaza-15-crown-5 --- p.94 / Chapter 4.6. --- Preparation of Tetrabromodibenzo-24-crown-8 --- p.95 / Chapter 4.7. --- Complexation of Tetrabromodibenzo-24-crown-8 --- p.97 / REFERENCES AND NOTES --- p.98 / APPENDIX --- p.109

Fluorescent labeling of biological materials using small organic dyes is widely employed in the life sciences and have been used in a variety of applications that include diagnostics and imaging. Quantum dots have the potential to overcome problems encountered by organic molecules and have been exploited for applications in biological imaging and in single particle tracking studies. The dithiolane ring can be exploited to attach a diversity of organic compounds to CdSe–ZnS core–shell nanoparticles. The introduction of spectroscopic labels as trans-azobenzene chromophores offers the opportunity to quantify the average number of dithiolane anchoring groups attached to each quantum dot. The transition from monomeric ligands with a single dithiolane anchor to polymeric ligands with multiple dithiolane anchoring groups can be exploited to raise the number of chromophoric labels adsorbed on each quantum dot. Systems showing FRET have been developed on the basis of supramolecular association of BODIPY based dyes or quantum dots as donors and organic chromophores as acceptors. Amino - terminated dyes and quantum dots associate with the chromophores through an ammonium moiety on addition of acid, thereby bringing them closer. Addition of base increases back the fluorescence intensity of the donor completely because of the dissociation. However a similar system with quantum dots as donor, show a very small restoration of fluorescence possibly due to non-specific interaction. In the next project, introduction of spectroscopic labels, in the form of BODIPY dye within the ligands offered the opportunity to quantify the average number of dithiolane anchoring groups attached to each quantum dot. Both fluorescence resonance energy transfer and electron transfer mechanisms are responsible for the quenching of quantum dot fluorescence and unfortunately does not make the system suitable for pH sensing. In the final project, BODIPY-oxazine based fluorophore – photochrome dyad has been assembled by a connecting triazole ring, such that the emission of the former can be modulated by the electronic and structural changes caused by the photoinduced transformations of the later. Further experiments need to be conducted on the fluorophore – photochrome dyads to switch the luminescence of the former with optical inputs.

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 219-222).

The phenyl ring in the crown ether, 13-phenyl-1,4,7,10-tetraoxa-13-azacyclopentadecane (I), was used a site for functionalizing the compound. Electrophilic bromination of the ring with tribromide ion gave a 95% yield of the product substituted in the para position. This product underwent lithium-bromine exchange when reacted with n-butyllithium. The resulting anion was used to prepare PhZPX and PhPX2 derivatives, X p-C6H4NCH2(CH2OCH2)4&12 The oxide of PhZPX was completely characterized by an x-ray diffraction study which showed, in general, that the phosphorus was tetrahedral, the nitrogen planar, and the crown ether ring organized with the oxygen atoms endodentate. Several attemps were made to nitrate or nitrosate the phenyl ring in the parent crown ether. Spectroscopic evidence obtained from the products indicate that the reaction led to mixtures of mono and disubstituted products. / Department of Chemistry

This study has resulted in a crown ether functionalized with both phosphine and phenol groups, 5-diphenylphosphino-1,3-xylyl-18-crown-5. The target molecule was obtained from a six step synthesis. 4-Bromophenol was treated in sequence with formaldehyde, dimethylsulfate, and phosphorus tribromide producing 4-bromo-2,6-bis(bromomethyl)anisole. The main intermediate, 5-diphenylphosphino-1,3-xylyl-18-crown-5, was obtained by treating 4-bromo-2,6-bis(bromomethyl)anisole in sequence with tetraethylene glycol, lithium iodide, and methyldiphenyl phosphonite. The lithium iodide cleaved the anisole-to-methyl group bond, and the methyldiphenyl phosphonite provided the phosphine group for the crown ether following a lithium bromine exchange reaction. The 31P NMR of the phosphine crown ether showed a single signal at 6 -5.9, showing consistency of a single product. The IH NMR of the phosphine crown ether in deuterated chloroform showed signals at 6 3.55-3.7 (crown CH2), 6 4.6 (benzylic CH2), 6 7.1 (d, J = 7.o Hz, crown aromatic CH2), and 6 7.2-7.4 (noncrown aromatic CH2). / Department of Chemistry

The phosphine(III) crown ethers, [4'-(N-phenylaza-15crown-5)]3P (1), [4'-(N-phenylaza-l8-crown-6)]3P (2), [4'-(Naza-18-crown-6)]2-Ph-P (3), and [4'-(benzo-15-crown-5)]3P (4) were synthesized by using an electrophilic bromination of the crown phenyl ring (with a tribromide ion) followed by the preparation of a lithium salt and subsequent reaction of the resulting lithiocrowns with P(III) reagents. The oxide of compound 1 was completely characterized by an X-ray diffraction study, which showed that structurally there is not a significant difference in P-O bond distances and OPC bond angles with [4'-(N-phenylaza-15-crown-5)]-Ph2-P=O. Thespectroscopic data of compound 1 and 2 were compared. It appears that 1 and 2 are similar in P environment; also they are more air sensitive than 3 and 4. In addition, a discussion about compounds 1-4, and a literature review of the preparation of phosphines are included. / Department of Chemistry