A series of unsymmetrical meso-tetra-arylporphyrins, substituted with redox active (3,5 di-tertiary-butyl-4- hydroxyphenyl (DtB4HP» and funct'ionalisable (4-hydroxyphenyl (4HP), 3-hydroxyphenyl (3HP) and 4-nitrophenyl (4NP)) substituents were synthesised and characterized by nuclear magnetic resonance spectroscopy, elemental analysis and fast atom bombardment mass spectroscopy. Their aerial oxidation in basified dichloromethane solutions (using 1 molar potassium hydroxide in methanol (1M KOH/MeOH) and l molar tetra-n-butylammonium hydroxide in methanol (1M tnBAH/MeOH») was followed by UV/visible spectroscopy, electron spin resonance spectroscopy and cyclic voltammetry. Basification with. 1M tnBAH/MeOH produced very little aerial oxidation for all the porphyrins in this study, but basification with 1M KOH/MeOH lead to substantial aerial oxidation of the 4HP series and the mono-4NP and trans-4NP porphyrins. Little oxidation in the case of the 3HP series occurred with either base. Cyclic voltammetry showed that in basified DCM solutions, one electron oxidation becomes more difficult as the DtB4HP groups are replaced by 4HP. In contrast, the trend in oxygen reactivity for the 3HP and 4NP porphyrins was not correlated with the first half-wave potentials obtained from cyclic voltammetry. An explanation for these differences is suggested in terms of: (1) the difference in the strength of electron releasing power of the three types (DtB4HP, 4HP and 3HP) of phenolic substituent. DtB4HP groups release electron density onto the porphyrin macrocycle more effectively than 4HP groups, which in turn release electron density more effectively than 3HP groups; (2) the relative availability to oxygen of DtB4HP electron density in the various series of porphyrins¡ (3) the relative ability in certain 4NP-substituted porphyrins to stabilise unpaired electron density over the macrocycle and its substituents.

by Chi-Shing Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 62-65). / Acknowledgements --- p.i / Contents --- p.ii / Abbreviations --- p.iii / Abstract --- p.1 / Introduction --- p.2-8 / Synthetic Strategy --- p.9-12 / Results and Discussion / Chapter A. --- Synthesis of the aryl triflate substituted and aryl bromide substituted porphyrins --- p.13-15 / Chapter B. --- Synthesis of the (alkynyl)phenyl substituted porphyrins --- p.16-19 / Chapter C --- Benzannulation of Fischer carbene complexes with (alkynyl)phenyl substituted porphyrins --- p.20-23 / Chapter D. --- "Palladium-catalysed cross coupling reaction of 2,5-dimethoxyphenyl boronic acid with aryl triflate or aryl bromide substituted porphyrins" --- p.24-28 / Chapter E. --- Synthesis of the meso-tetrakis(benzoquinonyl) porphyrin --- p.29 / Chapter F. --- Metalation of the quinone-linked porphyrins --- p.30 / Chapter G. --- Preliminary study on the electrocatalytic activity of the quinone-linked metalloporphyrin complexes of cobalt and palladium for the electrochemical reduction of carbon dioxide --- p.31 / Conclusion --- p.32 / Experimental --- p.33-61 / References --- p.62-65 / List of spectra / Porphyrin aryl triflate4 --- p.66 / (Alkynyl)phenyl porphyrin 9 d --- p.67 / Tetra(quinonyl)phenyl porphyrin 12a --- p.68 / (Naphthoquinonyl)phenyl porphyrin 13b --- p.69 / "2,5 -dimethoxyphenyl boronic acid 16" --- p.70 / (Benzoquinonyl)phenyl porphyrin19 --- p.71 / Tetra(quinonyl)phenyl porphyrin 23 --- p.72

Lee, Siu Yin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

by Man Kin Tse. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

No description available.

The sun is a bountiful source of energy for our planet. .With the advent of photovoltaic cells, man has begun harnessing the sun's radiant energy, turning it into a form more directly useful: electricity. Commercially available solar cells currently operate at about 13% efficiency, sufficiently high to make them a viable source of electrical energy. It is of great interest, however, to improve their conversion efficiency, and to lower the cost of production so as to make them more economical, and thereby reduce our dependence upon traditional "dirty" sources of energy such as coal and oil. It has been found that an electrode coated with a thin film of nanocrystalline titanium dioxide, a very inexpensive and commonly available semiconductor, can be sensitized with a strong light-absorbing dye which can absorb the energy of sunlight and then transfer this energy as electronic charge into the electrode. A cell containing such an electrode is capable of producing a photocurrent at an appreciable voltage. The search is on to find the best sensitizing dye. It must absorb as much of the incident sunlight as possible, be capable of strong adsorption onto Ti02 so as to promote electron injection into the semiconductor, be relatively cheap and easy to synthesize, and be photochemically stable. It was the intent of this research to synthesize and test such a dye, a porphyrin dyad. The dyad was to be made from an electron donating moiety, meso-tetrakis(4-aminophenyl)porphyrin (TAPP), linked by an amide bond to an electron acceptor, meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP). This material eluded attempts at synthesis, due to the poor reactivity of the aminoporphyrin and to the difficulty in ensuring that only one amide bond formed. Characterization of the monomers was carried out, and conditions for their chromatographic separation were determined. Recommendations for successful synthesis of the dyad are given.

From the green chlorophyll in plants and algae that we depend upon to transform sunlight into useful energy, to the red heme that carries oxygen to the cells in our bodies, porphyrins are the colors of life. It is not surprising then, that porphyrins have been actively interrogated as tools for diverse applications to improve biotechnology and medicine. With the goal of improving cancer therapy and diagnosis in mind, this thesis examines new modular porphyrin architectures. These constructs have interesting properties that extend beyond their originally intended use as phototherapeutic agents. In Chapter 1, a comprehensive background on porphyrin-based activatable photosensitizers is presented. In Chapter 2, porphyrin singlet oxygen and fluorescence quenching is examined in a model system with respect to Förster theory. Chapter 3 examines a new DNA responsive molecular beacon that was quenched using multiple quenching moieties and its application for nanoparticle aggregation. Chapter 4 describes extremely self-quenched nanovesicles formed from porphyrin-lipid conjugates that displayed a number of desirable properties for nanomedicine applications. Chapter 5 presents a brief discussion and some potential future directions of the research. It is my hope that the data presented in this thesis set the stage for new porphyrin-based approaches to make a translational impact in the battle against cancer and other diseases.

Binding studies were performed with a bisurea-picket porphyrin host receptor (a,a)-5,10- Bis-(2-(4-fuorophenyl)phenylurea)-15,20-diphenylporphyrin (1a) and TBA salts as its guest. Previously our group reported1 on the binding studies of tetrakis-urea-picket porphyrin (a,a,a,a)-5,10,15,20-tetrakis-(2-(4-fuorophenyl)phenylurea)porphyrin (3) and tris-urea-picket porphyrin (a,a,a)-5,10,15-tri(2-(4-fuorophenyl)phenylurea)-20-phenylporphyrin (2) using polar solvent, DMSO, where a strong binding preference was observed for Cl¯ anion over H2PO4 ¯, CH3CO2 ¯, and NO3 ¯. A crystal structure (Figure 1- 1, Chapter 1) of the tetrakisurea-picket porphyrin 3 - chloride anion complex showed the anion bound between two adjacent ureas and hydrogen bonded to the four NH protons. It also showed the presence of one DMSO molecule bound to a third urea. Previously it was hypothesized that the ubiquitous DMSO solvent molecule bound to the third urea arm of the receptor was facilitating the anion binding by coordination utilizing columbic force. Through the investigation described in this thesis it was confirmed that the system of tetrakis- and trisurea-picket porphyrin exhibit a binding selectivity that is facilitated by the incorporation of a solvent molecule in the binding cavity. This was evident by the reversal of binding constant that was observed for the bisurea-picket porphyrin • anion complexation in contrast to that of tris-urea-picket porphyrin • anion complexation and tetrakis-urea-picket porphyrin • anion complexation. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry / "May 2006." / Includes bibliographic references (leaves 71-73).

The research presented in this thesis deals with the synthesis, optical and photochemical studies of various porphyrin and/or fullerene based systems. The second chapter deals with the study of fullerene based molecules composed of C60 covalently linked to ferrocene and various nitroaromatic entities. Chapter three involves the study of molecules composed of zinc porphyrin covalently linked with ferrocene(s) self-assembled into supramolecular triads by axial ligation of imidazole bearing fulleropyrrolidine. The triad studied in Chapter four is composed of zinc porphyrin covalently linked to boron-dipyrrin which was selfassembled into a supramolecular complex by axial ligation of imidazole appended fulleropyrrolidine. Chapter five deals with the formation of a dyad complex composed of Zinc N-confused porphyrin axially coordinated to imidazole bearing fulleropyrrolidine. The compounds discussed in this thesis were studied by optical absorbance and emission, electrochemical, and time-resolved photochemical methods. These compounds were mainly characterized by 1H NMR, UV-vis absorbance, and ESI-mass. Binding constants for the supramolecular complexes were arrived using UV-vis spectroscopic methods. Also, B3LYP/3-21G(*) computational method was used to probe the geometric and electronic structure of the compounds studied. The triads studied in Chapter two revealed efficient photoinduced chargeseparation. Interestingly, the computed site of electron transfer using DFT methods was found to track the electrochemical results observed in the cyclic voltammetric experiments. The self-assembled triads in Chapter three revealed efficient charge-separation from the excited zinc porphyrin to the fullerene (C60) entity. Also, the triads revealed efficient charge stabilization due to the presence of ferrocene(s). The self-assembled triad in Chapter four revealed efficient energy transfer from the boron-dipyrrin entity to zinc porphyrin. The selfassembled triad exhibited energy transfer followed by electron transfer to the fullerene (C60) entity. In Chapter five the construction of a dyad composed of zinc N-confused porphyrin and fullerene (C60) was confirmed. Spectro- and photochemical experiments revealed efficient electron transfer from the porphyrin to the fullerene entity. / Thesis (Ph.D.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry. / "May 2006." / Includes bibliographic references (leaves 147-155).

The research reported in this thesis details the synthesis, characterization, electrochemical and photochemical studies of noncovalently linked porphyrin-fullerene based donor-acceptor systems. The first chapter gives an introduction that briefly summarizes the significant events that occur in natural photosynthetic systems, the importance of artificial photosynthetic models and finally, lists new developments in model biomimetic systems of this type. The second chapter discusses synthesis of control compounds and physical methods used in later chapters. The third chapter focuses on the investigation of covalently linked porphyrin-fullerene dyads. A discussion of the role of axially ligated pyridine in decreasing charge recombination rates can also be found in this chapter. The main investigations in the fourth chapter utilize noncovalently linked porphyrin-fullerene triads with two axial coordination bonds with an emphasis on the importance of structural rigidity and the orientation of the donoracceptor entities. The fifth chapter discusses the purpose of a secondary donor and the effect it has in charge separation and charge recombination rates for self assembled supramolecular triads formed via "two-point" binding. Noncovalently linked magnesium porphyrin-fullerene dyads and triads are presented in chapter six. The compounds contained in this thesis were synthesized and characterized by proton NMR and ESI-Mass spectroscopy. Binding constants were obtained by using UV-visible, fluorescence and 1H NMR spectral data. DFT calculations were performed to gain insight into the structural aspects and orientation of the donor-acceptor groups in these supramolecular complexes. Electrochemical and emissions studies (i.e. steady state and time resolved fluorescence, transient absorption) were employed to obtain free energy changes for electron transfer, lifetimes, charge separation and charge recombination rates for photo - induced electron transfer. / Thesis (Ph.D.)--Wichita State University, College of Arts and Sciences, Dept. of Chemistry. / Includes bibliographic references (leaves 189-199). / "May 2006."